Baseline AC is $3793 for 1000 SqFt Zone
Ok, had an HVAC out to my home today. He said the two-ton upstairs zone covering ~1,000 Square feet is “running properly, but he noted the refrigerent pressure was a couple of pounds low.” I ask, “is being two-pounds low considered low?” “No,” he replied. I then asked, “what would be considered low?” He paused for a moment and then said, “well, refrigerent isn’t anything you have ever seen and behaves in a way you would never expect.”
Ok, what the heck is that suppose to mean?
“Being on a little low on refrigerent can have a large impact on cooling capacity,” he finished. I then inquired, “how much should that zone have?” He then offered, “well … typically if its around ten PSI then we considered it low, but yours was at 15.” Ok, so I suppose he got it up to 17 PSI. Moving away from the tune-up portion of his visit I inquired about replacement of the unit.
“A baseline replacement Trane would cost $3793 and that is a SEER 13. You presently have a SEER 10.” To replacement the furnace it would be $5293 total, but I’m not touching the furnace as its more than capacle of heating the 2nd floor in the Winter.
“If you want to step up a notch to the next level we can install <yadda, yadda, yadda> 2.5 ton SEER 16 unit for $6400.” My heart just sank. $6400 for a half-ton more cooling capacity for 1,000 SqFt. I am in the wrong business. And had it not been for the fact that I had not conducted a geologic survey of my lot, I could have planned for a geo-thermal heatpump for the second floor (or whole house).
Quote #2 comes tomorrow.
Replies
That other quote was not for just a 1/2 ton increaase.
It was also for a bump from SEER 13 to 16.
I don't know what the rate of progress is, but on things like AC the prices start increasing expodential as the SEER increase.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
you want to know what good price are, pick up the grainger catalog. They sell HVAC units in there.
There is a Grainer's near me (~20 miles), but I never thought that they did this kind of business with general consumers. Also, how would I benefit from one-off costs and bulk costs? Are you gonna suggest next that I play uber-DIYer? :)
Funny fact:
It is 15ºF cooler outside at this moment (and in my attic) than it is in this bedroom that I have converted into an office. And no, nothing had been running during the night in this room. Maybe the room is radioactive? lol
I will go on record again, When it comes to HVAC, get the guy with the most trucks, most employees and been in business since 1976. He will have the reputation to stand behind his product. But if you wondering what a price is on a unit. look at grainger to see what they run in price. then the hvac contractor will have a markup on that. So if the unit is 75% of what quoted, then its a close price. If its 10% well, you sure look purity boy.
I will go on record again, When it comes to HVAC, get the guy with the most trucks, most employees and been in business since 1976. He will have the reputation to stand behind his product.
I can guarantee you, beyond a shadow of a doubt, that those qualifiers for choosing a HVAC contractor will NOT guarantee a job well done... or, even done right.
Edited 7/7/2007 3:12 pm ET by danski0224
Danski,Ya got any better qualifers?Yeah, I didn't think so. Well, have you got a better way to increase the odds of getting a good job?Didn't think so about that either.SamT
References from friends or family would be one place to start.
Bill, you are correct and I am not trying to ignore that fact. I am more concerned that two-ton existing unit isn't doing the job and the HVAC 'expert' says it is operating normally. The existing SEER 10 unit for one or more reasons isn't doing the job, and so far no one has determined why--in fact, they think its operating normally.
The recommended replacement was a 2-ton SEER 13, which currently is code-minimum, and for just AC its $3800/1,000-SqFt. To me, this is absurd considering the only thing I am getting from the SEER concept is operating cost savings and not actual cooling capacity.
All, I think I may have forgotten to mention something about the topology of my second floor. There are two openings to the first floor: foyer and family room. Both of these must be adding to the summertime heat load of the second floor, and potentially reducing the heat load of the first floor.
If this is the case then I would think it rational to include this fact in heat loading calculation when the initial system was sized. Am I nuts on this premise? Also, since there are a couple of 1st-2nd floor openings, how should draw and retun sizings be handled?
I also cannot ignore the fact that air is ejecting from the master bedroom because the master bedroom suite has four source vents (bedroom, bath, water closet, and closet) and only one return. And one last thing to mention (now that the wife just informed me) is that the HVAC technician said there was a 21ºF differential between air entering the AC system (warm side of evaporator) and leaving it. This wasn't on the quote paperwork, but on a notepad the wife had at her desk.
I am not sure how this measurement was conducted (I was at work; and HVAC will not come out without a 2x fee when I am home.). If I use the Fluke 62 Mini IR Termometer I am seeing ~10ºF difference at the coolest room's source/retrun vents. I'd have to guess this means its losing 5ºF from AC unit to room, and another 5ºF from room back to AC unit.
Couple of things leap out at me.
(1) the tech. was talking pounds of gas instead of suction or head pressures. The weight of gas in the unit should be listed on a label on the unit. He can extrapolate the amount of gas in the unit from the pressures and that listed number put no way can he read that amount directly.
(2) No leak detector with him ? Simple B.S. If he is doing service work he has a spray bottle of Big Blue or such liquid leak detector on the truck at the very least. He may not have a "sniffer" type unit with him, but most guys don't even need them to spot the tell tell oil deposits left at a leak site.
(3) The 20 degree delta T across the coil is ideal. It is checked with a digital or analog (dial) type of probe thermometer, immediately on either side of the coil. Look for a small 1/8" hole in the return and supply plenum of the AHU. Not there,----- he is jerking you around again.
BTW an IR thermometer is only reading surface temperature. Forget about using for air temps.
Someone mentioned that replacing equipment is more profitable than repairing it. It is, but service work is billed by the hour (portal to portal rate is from $65 to $80 per hour here), there is no loss in service work period. There are minimum charges for service runs, so the more runs a tech can do in a day, the higher the company's take. Pressure is put on the techs to get in, get out,... fix it if it is simple, f--- it, if is going to take more than xx hrs. min., and sell new if you can.
The absolute best way to handle HVAC companies IMO is to know enough about what they are suppose to do that your BS warning system goes into alert when they start talking bull. Call their hand on the the crap, move on to the next company and repeat the process. Your instincts and BS meter will let you know when you find an honest one, then don't be afraid to negotiate for the best price for service or equipment.
BTW if the guy was selling Trane equipment, he is an authorized installer/service company. Call in a complaint to Trane's regional distributor. They track their authorized contractors complaints as well as their success. Enough complaints come in and the guy gets heaved.
Dave
"All, I think I may have forgotten to mention something about the topology of my second floor. There are two openings to the first floor: foyer and family room. Both of these must be adding to the summertime heat load of the second floor, and potentially reducing the heat load of the first floor."I see that others have answers most of your question, but no one has answered this one.ABSOLUTELY YES. But I don't know how it is included in the calculations.My house is about 1600 sq ft. Because I am on a hill side it is "upside down". The main formal entrace is at the highest level with the garage. Then you drop down 1/2 flight to the 2nd story, then 1/2 flight to the a landing for the "basement" under the garage portion, then 1/2 flight to the first floor.The areas are connected with a single set of switch back stairs. No balaconies or 2 story areas.I have separate systems on the first floor and 2nd. And on the 2nd floor has AC.During the summer the 2nd floor stays fine. And the first floor is usually very comfortable also, but on the worst days it will be a little warm.That small entrance hallway, 1/2 floor above the 2nd floor, will get very hot.I don't know what you are asking the HVAC companies. But it should specify that you want some one to evaluate your distribution system.Even if the unit is undersized, just replace it will a bigger unit will still give you the air tempature differences..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Based on the little you have posted, I'd wonder how competent this person is. Whether or not the two ton AC can handle the whole house or not depends on a lot of factors, such as the exposure, heat gain, etc. Two tons covers 2,000ft^2 in my home and is still oversized.
I'm not sure if you're intending to add AC to the basement, but if that's all you're going to do, installing some zone dampers and barometric bypass on the air handler/furnace may be a more economical way to achieve zoning comfort without a big bill.
I may have not effectively related the information at hand. The two-ton unit is ONLY cooling the second floor zone, which is 1,000 SqFt. The only air cooling intended for the basement (which is cooler in static existence than the 2nd floor with so-called cooling) is a split ductless system.
Nothing that you relayed from the "technician" gives any indication whatsoever regarding the proper operation of your HVAC system.
Until you do a load calculation, check the ductwork for obstructions/loose connections, really bad and improvable duct installation, seal ductwork air leaks, check for proper airflow at the evaporator coil,... and find someone capable of using a thermometer, psychrometer and a superheat/subcooling charging chart (or reading the tables that might be in the unit)....
You are wasting time and money even considering a system replacement.
If the "technician" actually explained things to you in those terms, no way would I let them near my stuff... and it is probably worse off now than before.
If you spend big $$$ on high SEER equipment, and connect it to crappy ductwork, and don't size, install or charge it properly... you just wasted a boatload of money.
Here's a clue... there is way more money (profit) in replacing equipment than repairing it. "Technicians" are under the gun from the boss to *sell* stuff because there is more profit per hour in replacement compared to service call rates. Condemning equipment and offering easy financing is way easier than actually *fixing* it.
Unless your 1000 sq ft is all glass, in Death Valley, open to the outdoors all the time, or there isn't any insulation at all, has 16' ceilings, 2.5 tons of cooling is too much.
You are about to get bent over....
I can't do a load calculation, its not my field and I'm ignorant to that process. Unfortunately, it didn't occur to me to have them perform such an activity. I was a little bemused that the technician admitted to being ill-prepared (minus a leak detector), and have to take anything he said with a grain of salt--including that the existing system was operationally fine.
There is no way I am spending money like that. I find it absurd that anyone would spend that much money one so little space for so little return. Unfortunately, this is my only experience with HVAC companies outside of the original installer (and they were a-holes). And this crew couldn't offer me a quote on replacing ductwork (flex-->rigid), installing an attic fan/ventillation system, etc.
I guess I'll see what HVAC #2 will say.
You CAN do a load calculation. I have given this information several times before, including to you.
Go to http://www.hvac-computer.com. "Watch" the demo of the program on the site. Spend the $50 on a limited use license.
If you can use a simple tape measure, and know what direction your windows face, you can input the data into the software. It really isn't that difficult to use that program.... I can do it.
It will take just a few hours of your time the first time.
I can understand your frustrations, but customers and their desire to obtain something for nothing has created your typical experience with HVAC contractors.
Anyone with a set of gauges and a jug of Freon can claim to be a HVAC technician.
Although HVAC may not be "rocket science", there is a significant difference between installations "done right" versus just "done so it works" and even "done cheap". The worst is "done to get the bid"- which is what you get in most residential new construction in any price range.
Most customers will zone out and eyes glaze over when the differences between "done right" and "done cheap" are explained. Most just care about The Price, and without knowing what you are paying for, a comparison between companies based on Price is meaningless- yet customers base decisions on Price all the time.
Companies do not want to provide detailed information on proposals because 98% of the clients are shopping The Almighty Price and the rest want the information so they can get the equipment online or have their hack buddy do it for cheap.
Unfortunately, there are also companies that prey on the ignorance and emotions of the customer, and install junk at obscene prices.
Probably a lot of similar issues in many fields.
I second danski's suggestion to go with a heat gain / heat loss calculator. Like him, I found Hvac-calc to be a good calculator, easy to use, etc. In fact, I even wrote a homeowner review of hvac-calc. Since you can download a trial copy of the software, see if it makes sense to you before you plunk down $50 for the 2 month trial.
Last winter, we finally reached design-day conditions one night (9*F, 15MPH wind, 6AM) and I was pleasantly surprised to see that the heat loss I had calculated was spot-on. The heat gain is another matter, because Manual J, 7th Ed. does not account for external shading. Thus, my heat gain has been a lot lower than predicted. That said, if more of the 100-year-old trees around the house start dying, then I'll need more cooling capacity until the new ones come up.
Nuke, I guess I need more info on your system to get my head wrapped around it. You say you have a 2 ton system installed that is currently cooling only one floor, correct? What is the total number of floors, the square footage per floor, etc? Heat gain, like heat loss, is location-specific... house construction, location, orientation, etc. I would not let a technician dictate to me what the heat gain "is" unless he had one of two things: a record of the actual current AC utilization on a design day OR a heat gain calculated with parameters that make sense.
Installers are notorious for installing too much capacity "to prevent callbacks". Not only is this attitude wasteful (both for heating and cooling) because it impacts efficiency, it also impacts comfort since the AC system will never run long enough to reliably remove latent heat (i.e. humidity) from the indoor air. Similarly, a grossly-oversized furnace (as many are) will bake your family with short puffs of hot air, punctuated by periods of cold. A right-sized system will maintain a temperature...
Our HVAC installer put in the air handlers first, before I caught on. I then required him to install condensers that were matched, but a ton lower in capacity than each of the air handlers. Even though the system is "right-sized", it runs very little to not at all at full capacity, even on design days. Too many installers use a rule of thumb of "500 ft^2 per ton" to size their systems, these sorts of folk need to be shown the door. When a true professional shows up, they'll be able to do a heat gain, install a zoned system, and charge it properly. Pay the premium and enjoy the comfort + energy savings that result.
...oh, and I don't want to hear any more whining about the 13 SEER energy efficiency standard. :-P
... perhaps I am biased ...
... but I was but a whee cog in the process of setting it.
Two-story home on walkout (daylight) basement. The walkout basement portion spans the 55' width of the home and faces SW. There is a three (3) ton Trane unit for the 1st floor and a two (2) ton Trane unit for the second floor. No trees to offer protection from the sun, and medium to light colored gray shingles on the roof. All duct work is based on flex ducts. The 3-ton is in the basement, and the 2-ton in the attic.
House has an attached garage and one bedroom and a shared (Jack & Jill) bathroom sit on top of the garage, which consumes about 2/3 of the garage's footprint (~270 SqFt). Guessing the two-story foyer is about 160 SqFt and the family room 290 SqFt. Thus the net differences would be -160-290+270 = -180. Total living space is 2650 SqFt. (2650-180)/2=> ~1235 SqFt 2nd floor and 1415 SqFt 1st floor.
I need to breakout a tape measure for more accurate figures--sorry, I will do this. BTW, I just had someone over here that spent three (3) hours performing an energy audit of my home. I have confirmed its built out of Swiss Cheese. Damn those Swiss! :)
Problems identified were the house was leaking like an overworked hooker. Evidence of filtering dust at every duct connection at the plenum, and ever floor/ceiling supply and return register was shown. Yikes! The recommended number of whole-house air exchanges was 7.1, but mine was doing 13.5. Estimated cooling loss was 25% (1.24 tons), and the biggest offenders were the registers themselves.
I was told that the state of California will not issue a cert of occupancy unless the energy loss was below 10%. I do not know if this is true (unconfirmed), but this company guarantees their work to 5%. They have quoted us on fixing all of the leaks in all registers, flex ducts, canned lights, etc., and included our requested quote for inclusion of a pair of Aprilaire 5000 units (one per zone). Cost: $5300. Time to implement would take two full days and they include a re-analysis, which is required to prove the reduction in loss.
Ok, I am overwhelmed by all of this. I cannot believe my 1st floor has a 3-ton unit. No wonder it cools without effort. I thought the upstairs unit was suppose to be bigger. Maybe it is due to the 16'x18' family room that faces SW that they sized the 1st floor zone so large.
"Problems identified were the house was leaking like an overworked hooker. Evidence of filtering dust at every duct connection at the plenum, and ever floor/ceiling supply and return register was shown."What have I been saying?.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Nuke,So, over the thumb, you've got about 4,000 square feet to cool and the present installed capacity is about 5 tons. However, of the 4,000 square feet, about 1,400 are at least partially underground, reducing your heat gain down there. I would seriously consider the option to insulate, weatherize, and seal that ductwork. That's a savings that will keep on repaying itself. Furthermore, it could potentially allow you to zone the basement AC unit to cool the basement also once the load upstairs has been reduced. That figure for whole-house air changes - is that air changes per day? FWIW, we have 0.2 air changes per hour, i.e. one whole-house air change every 5 hours, or about 5 total a day. Granted, we could have been tighter, but that would have meant abandoning the historic windows...
Edited 7/7/2007 8:03 pm ET by Constantin
I believe that the individual stated 7.1 whole house changes per day was the target, and 13.5 was what my home was measured to be. Whatever the system was employed that is what they reached with the blower-door test.
Look real close at the floor over the garage. Very often that's a major leakage source.Ductwork in the attic needs to be very tightly sealed. Losses in the basement don't hurt that much (other than to possibly make the basement too cool), but losses in the attic are just burning money.Yes, odd to have a larger unit for the lower floor, even given a larger footprint. Usually if you can keep the top floor cool the lower floors are a cakewalk.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Hey Nuke,I've been reading your tale with interest as I'm suffering from a similar problem.Have you considered the option of getting the house sealed up first, re-analzye, and then make a decision on replacing the compressors? You may have enough capacity in the system that it will work properly once the leaks are plugged.Speaking of which -- how did you find your contractor that did the assessment? Yellow pages and looked for folks who would do an energy audit?Long term, can you put some trees in on the SW side of your house to block some of the sun? Your profile says GA, but you mention CA regs. In either case, both are sunny states and having the backside of your house facing directly into the hot afternoon sun seems pretty painful.I can't remember if you mentioned any ceiling fans in order to keep air circulating between the upper and lower floors. Obviously, you can't control the convection between the two floors, but you could help blend them together and balance things out.Having had to suffer through several expensive repairs on the current place, the best advice I can give is to take a step back, breath, and then re-focus on what your end goal is. Sometimes I get so fixated on a given solution that I forget to see the other options available.Glen
Happily no longer in AZ... :-)
Yeah, there are lots of ways to reduce cooling load:-- Seal ductwork leaks, especially in ductwork outside the cooled envelope.-- Seal home air leaks.-- Use curtains or blinds, preferably with a white backing, during the hottest part of the day.-- Run vent fan in shower and cooking area when heat/humidity is produced.-- Turn off unnecessary lights and other electric devices.-- Run room fans to redistribute air and gain the cooling effect of air movement on the skin.-- For the lower cooling system, whose ductwork is wholely contained within the cooled envelope, set the thermostat to "fan" to redistribute air. (Only do this with the upper system after you're confident that the ductwork is sealed.)-- For clothes dryer, install a fresh air intake in the same room as the dryer. Open the intake when the dryer is running, then close the door.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Dan, considering the internal diameter of the ductwork in the attic and basement, one could rationalize uninsulated rigid plumbing that passed though the interior space (inside the envelope). Heck, a smallish soffet could even help to hide it.
But this is a cookie-cutter home and the name of the game and cheap and fast. :)
If I hire the folks to resolve the problem based on their anaysis then I should have to be buying replacement equipment. I'm guessing spending the money, financed, would get me $100-120/month in 60-month payback. I suppose that if they implement the resolution and it doesn't work then I could always negate their proposal as their original conclusion (2-tons is enough for upstairs) was false.
I am still trying to figure out why I have a 3-ton unit for the first floor, though. Anyone have any thoughts on that one?
I am still trying to figure out why I have a 3-ton unit for the first floor, though. Anyone have any thoughts on that one?
That's what the contractor had on hand? Good a reason as any...
"I am still trying to figure out why I have a 3-ton unit for the first floor, though. Anyone have any thoughts on that one?"Could it be the units were sized for heat pump operation (gas furnace as back up heat only)? In heat pump systems around here, larger first floor systems are common. This is because the delta T during heating season is more than cooling season. Winter 35°F outside (before gas back up cuts on) to 68°F inside is 33°F. Summer 93°F outside to 73°F inside is 20°F. And if one sizes for electric back up, the winter is 15 or 20 degrees F outside.....Frank DuVal
I do not know how to respond to this. There are no heat pumps going into new construction homes that I have seen. The entire subdivision and all those around it are based on AC+heat and not heatpump+heat.
>> BTW, I just had someone over here that spent three (3) hours performing an energy audit of my home. I have confirmed its built out of Swiss Cheese. Damn those Swiss! :)
Problems identified were the house was leaking like an overworked hooker. Evidence of filtering dust at every duct connection at the plenum, and ever floor/ceiling supply and return register was shown. Yikes! The recommended number of whole-house air exchanges was 7.1, but mine was doing 13.5. Estimated cooling loss was 25% (1.24 tons), and the biggest offenders were the registers themselves.
I was told that the state of California will not issue a cert of occupancy unless the energy loss was below 10%. I do not know if this is true (unconfirmed), but this company guarantees their work to 5%. They have quoted us on fixing all of the leaks in all registers, flex ducts, canned lights, etc., and included our requested quote for inclusion of a pair of Aprilaire 5000 units (one per zone). Cost: $5300. Time to implement would take two full days and they include a re-analysis, which is required to prove the reduction in loss.
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I think you are on the right track here. When building homes under the Energy Star program they taught us that the typical HVAC installation has between 15 and 25% duct leakage. Their goal (requirement) was something like 2% max. The real killers are the ducts that are leaking badly in unconditioned spaces - ie in the attic.
If you were to have the people who did the energy audit tighten up your house, the amount of savings on your energy bills might be significant.
Regarding the 2ton upstairs and 3 down downstairs, I won't comment on that except to say that the Manual J calculation will answer that definitively. Seems like the energy audit would have included that. Maybe it did?
Just throwing more tonnage at your problem is what I'll call the Hummer approach. Bigger is always better - right? :-) NOT!!! BTW - Here is one Q that hasn't been brought up - does the upstairs unit (2nd flr) run constantly? What % of the time would you say it runs? As mentioned above, having a oversized AC unit that runs for short bursts is a bad thing. Like they said, the humidity is not removed from the air, so, even if the air is at 70 degrees F (for example) it may not be comfortable because on the humidity contained in the air.
Back to the energy audit, what is the specific need for the Aprilair electronic air cleaners? Is there another issue you haven't mentioned? Does someone living in your home have a serious respiratory problem like asma, etc? I can't see how these would directly help with the problems that have been discussed in this thread, and I'm gonna guess that that $5300 you mentioned might be reduced to $3600 if the job was done without the air cleaners. The air cleaners might even reduce the efficiency of your HVAC systems - although I'm just guessing there.
Matt, the wife and I are serious considering the proposal on sealing the leakages, but ducts are only part of the leaky problems. For instance, even while I had the fireplace opening sealed (reclaimed as wall space for the flat-panel TV) there are other natural openings in the envelope that leak in excess.
Conveniently, the blower-door test covered a door that either the frame bottom or door bottom has warped on the first floor. I never considered this more than a minor annoyance as its easy to cool that floor in warm season and heating that floor in the cool season is almost impossible due to the 18' ceilings directly adjacent.
Then there is the three-year old nobody can fix for any dollar problem with the wife's study and upstairs bedroom window. I've mentioned those problems on numerous occasions as being impossible to find someone to ACTUALLY PERFORM THE REPAIR. Heck, I've been willing to write blank checks but I have yet to find any contractor confident they can fix that chronic problem. As such, I have wall and ceiling completely open to the brick-OSB air gap.
Sometimes I feel like I am trying to put out a small fire with gasoline. I know I can drown it, but I am given a coffee mug to dispense the gas on the fire. So, even if the audit company can recognize those other leakages they can do nothing for me. As a result, their measurements, both before and after, will be skewed like political statistics.
I understand fairly well the energy audit testing process and test results, although as far as remediation, my experience has largely been on the front end of things - building houses to meet the specs. Repairing houses is in direct conflict with one of my main professional goals - which is to build so they don't have to be fixed, since guess who fixes the houses I build... :-)
I do remember some time ago you stating that you had a problem that you were practically willing to issue a blank check for resolution... I also have a really vague remembrance that it might require removal of brick veneer.
Just to let you know that some residual good actually does come of your posts here, yesterday I talked to the main guy at my HVAC contractor about their duct sealing methods. Not that it helps your situation but a trend that I'm seeing is that some of my subs are becoming more oriented toward "energy conscious building". For example, my framer now does energy corners as standard - now if I can just get them to do energy 'Ts'. My HVAC sub uses mastic on duct connections as standard, whereas 3 years ago they didn't - it was an extra charge. My insulator now sends out a guy to preiinulate prior to the framing inspection which includes the fire/air stop and he insulates behind electrical devices (boxes) and any plumbing that had to land in the exterior wall; I've been bitching at the insulation mechanics for years about this behind the boxes stuff...
Another small consolation is that due to your and other's ongoing posts about the questionable quality that is accepted by the general home buying public at large, there are at least a few more people out there - you included - that kind of have X-ray vision when you look at those cheap sq footage track homes built by most of the large national builders. This shores up my position a bit as a small builder (actually working for a small builder) - we know we can't compete with the nationals - so we have to build a better product - even in less expensive homes. Still - national builders are going strictly after volume sales numbers, so if it is cheap sq footage the majority of home buyers demand, that is what they build... It is the homebuyers who control this stuff... So really they should be pointing their fingers at themselves - not the builders. These nationals have large teams of punch work guys though :-)
BTW - back to your situation, what is the need for the electronic air filters?
Regarding your front door assuming that is where they installed the blower door - many doors these days have adjustable thresholds - might that help your situation?
Another thing I meant to say in my previous post; you mention SW exposure to the hot sun. You never really said what kind of glass sq footage you had in this SW direction but I wonder if some kind of solar tint film applied to the glass would help? Here, they even sell the stuff at blowes - and it isn't real hard to install - just a little trying on one's patience :-). BTW - our NC building/energy code is getting ready to change such that the only way the specs can be met is via low-e windows, so even the nationals will be forced to use better windows. I'm thrilled... (some people are easily entertained). ;-)
Central air filtration was due to the years we've spent dealing with heavy dust inside the home. We thought it came in naturally and not through leakages.
The blower test was done on the kitchen door. I have french doors on the front and his setup could not adjust for a 1-door narrow fitting, or 2-door wide fitting. So, he used a normal kitchen door, which faces the SW direction along with the rest of the backside of the home.
I have a lot of windows on the SW-side of the home, and only one facing NW, none facing SE, and a bunch more facing NE. The amount of sun, and thus the amount of warmth the backside (SW) get's is considerable, but neither zone has a problem with cooling that side of the house.
Windows and doors are double-pane, but not of the low-e variety (remember, cheap builder). All of the windows with SW exposure have window treatments that are light/white on their exterior side and dark on the interior side.
The sealing effort being proposed is bringing up additional questions. While I mentioned a) about feeling air in the Winter coming through the electrical outlets on the exterior wall in the kitchen, and b) the person pointed out fine dust (almost like soot) on its faceplate, nothing was mentioned to address these kinds of problems.
I guess I'll need to inquire on a more detailed proposed effort and hold off on any Aprialaire installations until I can see proof of a reduction in dust (since they are saying its duct leakage result). Curious, once these people are trained in performing energy audits and sold the equipment to perform as such, who regulates them to insure they are practices what they have ben preached?
Are those electrostatic cleaners or simply the extra-thick pleated units? For some reason those run $300 or more, plus extra if they include electronics to tell you when to change the filter. But they're probably worth it, just in terms of reduced filter changing frequency and lower back pressure on the furnace/AC.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Have a look:
http://www.aprilaire.com/index.php?znfAction=ProductDetails&category=7&item=5000
I've seen the units sold for in the $450-600 range (not installed) on a variety of Internet resellers, and also ePrey. I've previously ben quoted $910/unit installed by the HVAC company I initially brought into my troubled home this year.
So, if I figure the energy audit is rolling up a quote for $5300 to fix the leakage problem and install a pair of these units then the repair by itself would be about $3300. Of course, I am waiting on confirmation on that.
Edited 7/13/2007 5:39 am ET by Nuke
I'm guessing they threw those in because you complained of the dust (and it's a profitable sale). They won't signficantly improve efficiency, but are a little better than the standard pleated filters in terms of back pressure, I suspect.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Those Aprilaire 5000 filters are nice.
I would be interested in seeing pictures of your furnaces and ductwork. Care to post some?
I have taken some pics of the attic with the ductwork. I am having difficulty getting them viable on a webhosting space and there is difficulty in posting them directly to FHB. Even with 640x480 resolution and compression they are getting around 100KB/pic.
100KB is fine. It's the 3MB pics that irritate people.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Just load them on your computer and upload to Breaktime. No need for web hosting :)
First 10.
And the next ten. Unintentionally posted #11 twice. Sorry.
And the final batch (nine).
Strange roof -- never seen that sort of angled "knee wall". It looks like you have some areas of raised/dropped ceiling in the top floor (based on joists I see exposed). These are common sources of air leaks (around the edges).The dust pattern on the filter suggests that the air intake is restricted -- not fully cut out just ahead of the filter. In itself not a problem, but suggestive of carelessness elsewhere. Hard to tell for sure, but doesn't look like the air return duct is adequate in size. (Is there another one we don't see?)Don't have any real experience with the flex ductwork, but it seems sloppy (though probably not the worst anyone's seen) and it looks like flow is likely restricted at some of the attachment points. Seems like a trunk running the length of the attic would make more sense.Insulation doesn't look all that deep. Could stand to have more, I suspect.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
"It looks like you have some areas of raised/dropped ceiling in the top floor (based on joists I see exposed). These are common sources of air leaks (around the edges)."
I believe the builder originally intended on 8' ceilings for the second floor, and then changed his mind due to the competition. Instead of adding a 12" wall addition, this clown had them raise only the bedroom ceilings by 12" which is why you see the raised/dropped areas. Now add an addition section for the master bedroom trey ceiling, add blown fiberglass and the look of a moonscape is there.
BTW, that used filter is ~60 days old. While the rating was 90days the dust problem makes even 2/3 any rating to be reduced. The whole filter has dust on it, but the larger portion has heavy dust on it. And to show you exactly how much is 'getting through' I'll post more pictures Monday evening.
I am a little bewildered why you would run a supply ling adjacent the roof. I guess the nearness to the actual roof is suppose to be cooler than the attic floor? BTW, the length of the attic (long axis) is 55'. The HVAC is about dead-center. You can only guess what those run lengths are.
Overall, the job does not look too bad. I have seen worse.
Although the flex is run fairly neatly, there is too much of it. Flex should be minimized to about 5 feet total on each branch run. If the room needs a 6" duct, the flex should be upsized to 7" or even 8" to compensate for friction losses. A room by room load calculation with that computer program I mentioned has a duct design feature.
The short plenum box on top of the air conditioning coil does not distribute the air evenly. There should be some rectangular (or round) ductwork up there. The front and back of the A coil (where the copper lines go into the box) is flat, so there isn't much air above that point compared to the sides.
There should be enough room on the return side of the furnace for a 14" x 23" hole for the filter. The dirt pattern shows less.
There is a great deal of what looks like dust at the filter access door. If the furnace is sucking in hot attic air at that opening, you will have a dramatic loss of AC capacity. The bottom of the furnace box is perforated for easy panel removal- tape those seams with foil tape (and remove the blower to get to the back).
The return plenum should be larger.
The refrigerant lines should extend vertically at least the height of the coil before going down to prevent liquid migration to your condenser. This will extend the life of your unit.
If the flex duct and collars are not sealed, that is a major source of leaks. The duct sealer needs to be placed *under* the inner liner before the connection is made. Sealing the outside does no good.
The flex is pulled tight, it looks good, but the connections may come loose- especially if duct tape was used.
Your flex duct should be a minimum R-6.
I didn't count too many supply runs.
All bedrooms have a single supply and single return. The master bath, its water closet, and the closet beyond them all have supplies and no returns. There is also J&J bath with a returnless supply, and a third full bath with a supply and no return. And this bothers me.
If I close the master bedroom door leading to the hall I can feel a considerable flow of air at the door-carpet gap. I suspect the master bedroom return is undersized for the four supply registers it seeks to handle. Also, the two other bathrooms have returnless supplies that must also be accommodated by the adjacent bedrooms--otherwise the bleed to the hallway to equalize the air pressure.
I'll post some additional pictures for you and Dan regarding the raised/dropped ceilings and their potential for leaks. I see no evidence of air passing through a framed/drywalled intersection, but I see plenty of dust accumulating at the returns.
Typically, bathrooms do not have a return duct. Too many issues with moisture and odors being brought back into the system. While the exhaust fan is on, conditioned air from the rest of the house is brought into the bathroom.
In an ideal world, there should be a return duct for each supply. A compromise is one return for two supplies.
One supply for each room is fine- as long as it is sized properly. Residential bids are usually tied to the number of duct runs, so a smaller number of runs means a smaller price. However, if your supply runs are only 6" (or, a long run of 8" feeding two 6"), and they are all in flex, then there is a duct problem.
Adding perspective to the [notorious] second floor ... with no signs of leakages around the canned lighting, the attic access panel, or behind the supply/return register grills (on the grills, yes, behind then, no).
#106 shows the soffeted ceiling in the master bedroom with the supply register.
#108 shows the siffet corner detail, which examples a non-evidental leakage situation.
#110 is the master bedroom return, minus the grill. no evidence of leakage in the form of dirt/dust around the sheet-metal duct collar and surround drywall.
#114 the two-story (18') foyer just outside the master bedroom, the top of the staircase, and just out of sight (to the left) the warmest room on the floor facing NE.
#115 is the warmest room in the floor/house, its supply register, window treatment, crappy Anderson window, etc. (doesn't show opening in wall beneath sill)
#116 is the return register for the warmest room on the floor/house. A lot of evidence of dust accumulating on the return-leg.
#117 is the supply registerfor the warmest room on the floor. Strangely enough, the supply registers never show a dust-of-magnitude problem. Sure, some six-year old worth of fine surface evidence, but nothing like what is seen on the returns.
#122 is the other opening between the first and second floors. Immediately off to the right is a door to the bedrooom over the garage. This bedroom shares a J&J bath with the warmest room. Warmest room is NOT above the garage. The two-story family room faces SW. Notice the blanks on the upper windows and the dark window treatment (interior) with white cloth on the outside. This room is always easy to cool.
My thoughts are still the same....
You are going to have to seal up the framing around that window.
You need to do a room by room load calculation.
The ductwork in the attic will need to be changed for optimum performance.
I bet some new supplies and returns will need to be added.
There is the possibility that the original contractor messed up and installed the larger unit on the first floor instead of the second.
Agreed. Yet, none of these were really caveated by the energy auditor, which is the representitive of the HVAC company making the proposal.
Here is a question for you ...
How expensive is it to install all new flex-duct? If they are going to 'seal' the '"leakages"' I would expect that an ethical company knows how to install ductwork in a manner not requiring post-audit sealing, right? In other words, an HVAC company with a success, reputation, and proven skillset should be able to install ductwork that would never need sealing.
If this is the case, why not just rip out all the questionably-installed ductwork and install new flex-duct? I would think that would make it easier and not play tag-your-it in attempting to work with what someone else installed in a crappy way.
Based on the images of the second floor and attic, how expensive should it be to re-duct the second floor (based is completely accessible as well)? And since this auditing company doesn't do sheet-metal ductwork (they are pro flex-duct themselves), I would think installing new flex duct and properly sealing the joining locations (collars, etc.) would be easier than monkeying with what is 'in-place.
BTW, the non-Aprilaire quote is ~$4100. This is for sealing treatments. WOW
HVAC companies like flex duct because it is cheap and fast. Flex provides the conduit for the air, it is insulated and comes 25' to a box.
If you rip out what is existing and just replace it with new, then nothing is accomplished. Your initial design is flawed.
All joints and connections on any type of ductwork require some type of sealant. Doesn't matter if it is flex, ductboard or metal. The amount of sealant is dependent on the quality of the installation.
No one cared about sealant before because energy was cheap- just put in a bigger unit. As sizes come down to where they are supposed to be, the other bad installation and design practices come to light.
Builders still don't care about it because it costs money. If an HVAC company puts it in the bid, they won't get the job. The only way to level the playing field is when the town requires it by code.
In other words, an HVAC company with a success, reputation, and proven skillset should be able to install ductwork that would never need sealing.
Change the trades around, and that statement can be applied to anything, yet customers still have trouble finding qualified help that can do the job correctly.
I have no idea what a "fair" price is- especially for your area.
Before you add more money to the AC unit add more insulation! 14" of fiberglass isn't all that great and it wouldn't be bad to add 8" more.
Want to supercharge your AC? Have a spray foam insulator add just a couple inches of foam to the underside of your roof. Attic temps will drop dramatically.
Too much emphasis on increasing capacity and not enough on reducing heat load.
Beer was created so carpenters wouldn't rule the world.
I am in Mississippi, if two identical houses are sprayed with foam on the underside of the roof deck and one house is in full sun and one is completely shaded, will the shaded one benefit as well? I am curious about this.Nobody is as good as they seem, nobody is as bad as they seem either.
You'd be amazed at how well spray foam works. Imagine a strofoam cooler wrapped around your attic. It's not a cure-all, but, like any insulation, it's one of the few building materials that pay for itself over time. That makes it pretty cheap.
Beer was created so carpenters wouldn't rule the world.
Too bad it still considered a luxury item in these parts and as such the costs are more than doubled where it is considered a luxury.
Don, how much per board-foot are they pricing near you?
The supply registers never show dust because it's filtered out by your furnace filter. But the unit could still be creating negative pressure and causing dust to be drawin in through cracks in the envelope.Tape a sheet of plastic across an open window and see whether it's drawn in or out on a still day with the house closed and the upper unit running.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
The baths should have fans to exhaust moist air, and returns would interfere with those fans, drawing the moisture throughout the house.This seems to cover it pretty well -- note that raised ceilings and dropped ceilings tend to have similar issues:http://www.energystar.gov/ia/home_improvement/home_sealing/DIY_COLOR_100_dpi.pdf
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
>> If the flex duct and collars are not sealed, that is a major source of leaks. The duct sealer needs to be placed *under* the inner liner before the connection is made. Sealing the outside does no good. <<
So - let me get this straight. The best way to seal a flex duct to metal collar connection (at the trunk or at a boot) is to:
apply duct mastic on the metal collar, pull on the flex duct inner sleave, tape flex sleve to metal collar with a good grade of duct tape,install a panduit strap(large cable tie) over thatpull the outer sleve and insulation over that andinstall a panduit strap over that.
Is that right?
I'm having a discussion with my HVAC contractor's guys about this. Unless I'm confused, the above is the way E-star inspectors had us do it before (another HVAC co and another builder I worked for) and current HVAC guys are saying "why would you want to do that" like I'm some kind of space being. HVAC CO management is saying yes, that is what we do - it's a big company, so internal communication may be lacking. I've gotta work with these field guys so have to be carefull. If I PO them, they will start charging me extra for every little problem, but I want to build above average quality houses. As it is I'm not paying the extra for E-star install, but still want good work.
If I was doing it...
Seal the collar to the duct, wait for the mastic to dry before attaching flex.
Apply mastic to the collar before the inner sleeve of the flex duct is attached.
Apply Panduit strap- not too tightly, though.
Pull insulation over, then strap that.
Allowing the mastic to dry on the collar first gives it a chance to seal. Moving the collar around while attaching the flex while the mastic is wet will open small leaks. Yes, it takes more time, but the benefits are long term.
Duct tape is useless.
HVAC field guys might be on the bonus program, so steps are skipped to cut the hours on the job.
yea... today I had a conversation with hvac inspector. He told me that per the NC 2006 mechanical code either tape or mastic and a strap was acceptable.
He told me that some time ago - maybe 2004 they figured out that the taped together assemblies don't meet flame spread rating requrements, so they cut back on the glue on the tape. Now it doesn't work so good...
Anyway, I'm gonna meet tomorrow with the HVAC field supervisor to discuss this thing about sealing flex to collars. He already told me "if that is what you want we will do it", I just didn't like being treated like I was from outer space... :-) I think he didn't want to admit that his guys weren't doing what they were already supposed to do - per the "bug guy" at the company.
Thanks for the confirmation.
Got up into the attic and took some more pictures.
#005 is a close-up of a flexduct mating to the front of the plenum. Is that mastic (sp) I see at the mating joint? The outer layer of the flex isn't pulled that tightly up against the plenum. Plenum wall temp on exterior was ~91ºF but that joint measured 15ºF cooler.
#007 shows bot ducts interfacing the front of the plenum
#008 shows two flexducts on the interfacing the right side of the plenum. In all instances the joint temps are 15º or more cooler.
#009 shows two return ducts interfacing the lower plenum.
#011 shows the lower plenum interfacing the return blower cabinet
#012 shows a backed up view of the two frontal supply ducts and the zip-tie/cord used on the outer portion of the flexduct.
#013 shows a rather tight turn that might 'pinch' the air flow.
#014 is questionably the same as #013.
#016 shows the splitting of one supply into three supplies for the master bath, water closet, and closet.
#017 is my mystery question subject of the day: I measured 75-76ºF temp air blowing out of this T-fitting.
#018 another view of the front & right side upper plenum (supply)
#020 & #021 are my three year old nightmare opening resulting from water that got to the drywall ceiling of the bay window without the masons installing through-flashing between this window and the bedroom window above.
#022 is my home. :)
#030 is the replacement standing-seam metal roof to solve one of three water infiltration sources that caused #022.
Now let me post the pics. :)
First batch.
Second batch.
Photo #12 plainly shows a gap between the ductboard and the metal collar.
Photo # 17 shows gaps around the AC lines where they enter the coil, and it also shows a flue pipe that (1) looks unprofessional and (2) appears to be disconnected.
The grey stuff you see is duct sealer. In all pictures, the application looks thin (water based stuff isn't expensive, so use enough to do the job...). Sometimes, it looks like it was applied on top of the flex. If it isn't put on right, it does little good.
The outer liner should be tight to the plenum, otherwise there is exposed cool metal in the attic.
Some of the bends look too tight, but that is a smaller problem than the long flex runs.
>> While I mentioned a) about feeling air in the Winter coming through the electrical outlets on the exterior wall in the kitchen, and b) the person pointed out fine dust (almost like soot) on its faceplate, nothing was mentioned to address these kinds of problems. <<
You can get gaskets for electrical boxes at a home center to help with that problem. It's basically just a thin piece of foam that is shaped like the cover plate. So you remove the cover put the foam in place, and replace the cover place. So easy a caveman could do it. ;-) They come in double, single, switch, outlet, etc configurations. I'm thinking they are a buck or 2 each.
Just as a matter of interest for you and other BTers on a trip a while back to Minnesota, being the building geek that I am, I had to visit some construction sites. What I saw was that pretty much all builders used special electrical boxes on exterior walls that had built in rubber like gaskets that sealed both where the drywall meets the box and where wires enter the box. I've never seen these used in the SE USA though. See attached pics.
>> I have a lot of windows on the SW-side of the home, and only one facing NW, none facing SE, and a bunch more facing NE. The amount of sun, and thus the amount of warmth the backside (SW) get's is considerable, but neither zone has a problem with cooling that side of the house. <<
If I understand the general layout of your house, at least part of the problem may likely be that with the 2 story foyer (and another high ceiling room?) there is a lot of heat potentially being generated on the main floor that is migrating to the 2nd floor via the stack effect. So the 2nd floor not being able to keep up may be as much of a symptom as it is the problem. Again I ask the question: How much time does the upstairs unit run vs sit idol during the heat of the day?
>> but neither zone has a problem with cooling that side of the house. << If any one zone is heating/cooling properly in one area of the house and not in another area the indication is that the air distribution system is not balanced properly within that zone. There should be dampers in each supply line where it connects to the plenum. These can be adjusted to move more conditioned air to one area and less to another. These slam bam HVAC companies normally just leave the dampers wide open. I would think that part of the energy audit process should include verifying that the system is balanced. the ones I've had performed did, but that was a little different because it was part of the home construction process.
A classic example of an improperly balanced air distribution system would be a small bathroom in the center of the house - with no exterior walls. If this bath has a supply duct & register, the damper should be cut back to allow significantly less airflow to this room. In some cases the ill heated/cooled area may need another supply duct and register.
Another part of getting proper air distribution is the return air path to the return registers. I'm guessing your house probably has 1 return per floor. If a room has a supply duct, but the door is often kept shut, and there is not a pretty good sized gap below the door, air may be more or less trapped in that room. This can be addressed with adequate undercuts on doors - say 3/4" min, or by installing high/low passive registers on either side of a wall in the same stud bay.
Edited 7/13/2007 7:17 am ET by Matt
I'm confused as to the layout of the house. You say "upstairs" and "basement". Is this a one-story house with (finished?) basement, a two-story "split entry" house (the bottom floor is about half below ground), or a two story house plus basement?
With a split entry or true basement the lower level contributes very little additional cooling load unless it has exceptionally large windows. The slight additional cooling capacity needed to handle the bottom floor could normally be gained by tightening up ductwork, improving attic insulation, using heat-rejecting blinds, etc. A zone system (with automatic dampers) would help go equalize temps in the house.
Dan, everyone, when I say "upstairs" I mean the second floor. The basement isn't being considered a floor in the 1st/2nd floor referencing. Sorry for the confusion.
Get ready. Having installed a couple of them in 4,000 ft homes, the price was easily $60,000 +.
Nuke,
Think outside the box here.. If the problem occurs only on extremely hot days then why not supliment your A/C on those days with a simple window A/C unit?
Need a few thousand extra Btu's? Pop in a window unit! I've seen high SEER units on sale for a few hundred dollars. Once the extreme heat is over, remove the window unit..
i can't help with design or problem shooting but i buy alot of equipment... mostly goodman some coleman.... a 3ton 13seer unit costs me (last week) $985... a 3ton 10seer replacement compressor only cost $285
i have about 3200sf with 3 tons down and 2 tons up... the up has an open section overlooking the den (solid half wall) and an open stairway... if i close off the opening to the stairway with anything... card table hang a blanket anything to keep the cool floor air from falling down the stairs the temps upstairs drop big time (found this out when the down AC went out one hot summer weekend and we all moved upstairs)
i don't know how one would control this cool air drop with large open areas...
if you want to know prices look on ebay tons of guys sell new equipment online
p
You are adding to my stress. :)
If we were talking about my basement I would venture into the DIY split-ductless systems and even consider buying online (maybe even from ePrey). Unfortunately, this is finished spaces. Still, you point and offering is well taken.