Moisture problem/heat loss
Hi all. Looking for some input on this situation. ICF home in western MI. Built it for myself and moved in just before Christmas. 2600 sq.ft. ranch with 1400 full basement (unfinished) and 1200 crawlspace. R-50 cell in ceiling, Andersen windows, geothermal heat. I followed the advice of a company called Energy Wise Structures on sizing the geo unit and did not install a heat exchanger. We should be paying about 150 -200 per month for our electric. This month it will be over twice that. We also have moisture on all of our interior glass which pools up and lays an the sills. The humidity levels are around 65% in the house. I’ve had the hvac guy who installed the system out several times, as well as another reputable geo guy and they can’t seem to figure out 1 why my bills are so high and 2 where the moisture is coming from.
This house was supposed to be a model of energy efficiency and indoor air quality and right now it is neither. The hvac guy installed a make up air tube that runs from my attic through a wall cavity and down to just above the floor in my basement. This is a 6″ pipe. The wall where it runs through my master closet gets so cold that my clothes that hang against that wall actually get wet and the wall weeps water from the condensation. This tube will dump cold air onto my basement floor when I’m not running any exhaust fans, dryer,etc. It appears that my house is in a constant state of negative pressure,yet if I were losing air to the outside I would think my humidity would drop. We are all confused and trying to problem solve this. I should note also that our temps have been 0-15 with heavy snow the past two weeks. I have almost no icing on the roof,just a few small icicles where the valleys come together at the bottom so I don’t think we’re losing heat up top.
Any advice or suggestions would be greatly appreciated.
Replies
Newly built homes contain a lot of moisture, as you have probably heard -- drywall mud, paint, damp concrete. It takes one or two years for a new home to fully dry out.
It sounds like you have the mistaken impression that you can have a healthy house without operating a mechanical ventilation system. You can't. Air exchange is good. You don't have to use an HRV or an ERV -- you can use exhaust fans. But they need to be designed for whole-house ventilation; they need to be sized according to ASHRAE Standard 62.2; and they have to be operated for most of the day.
Finally, you need to understand all potential moisture sources and investigate whether they are problems in your house. These could include: damp soil around the basement footings; lack of poly under the basement slab; a damp crawl space; indoor firewood; too many houseplants; lots of cooking and showers. Use common sense: reduce the indoor humidity levels, and ventilate.
I'll give you some more specifics abou the home. Walls were poured in Sep. 05, drywall, slabs, paint- winter 05-06, wood floors- spring 06. The basement floor has 1" sigid foam under pour, crawlspace has concrete floor. There has never been any sign at all of water in the basement. No firewood, a couple small plants, 3 showers per day using a bath fan, 2 adults, 3 kids, 2 cats, average amount of cooking
I was instructed by Energy Wise Structures ( who claim to have consulted on thousands of ICF and SIP homes) that an air exchanger wasn't necessary as hvac contractors typically oversize their units esp. in super tight houses. They claim you will get enough air exchanges through windows, doors and normal traffic into and out of home. In fact, my windows all have ice forming on the outside glass where the condensation that has collected on the inside has leaked through and frozen.
As far as a whole house fan goes I understand what your saying but won't my heating costs increase even more if I'm pulling all that conditioned air out of the house?
Also we left the home for a weekend and saw no drop in the moisture reading for the period we were gone.
Like I say, use common sense. If your windows are dripping, your house is too wet. In the winter, ventilation will lower your indoor humidity, so start ventilating. Since it sounds like you are in the process of rotting out your window stools, I would stop worrying about the slight increase in energy cost from ventilating your house. For heaven's sake, turn on your bath exhaust fans and leave them on for 24 hours a day, at least until your windows dry up. Common sense.
There's a similar (but VERY abbreviated) question on the This Old House forum? Was that you?
Nope. Wasn't me, but I'll check out what they said
You better install a HRV, (heat recovery Ventilator. I have seen the 'attic ' pipe used before and it does not work, and will cause the condesation created in the cold to damage the structure. All the heat and moisture rises to the attic ( as if it was a chimney) and when any air leaves as in when an exhaust fan is used or doors or windows are opened , air is pulled out of the attic. You do not need this size of make air intake as there is no combustuion air used and needed to be replaced. The HRAV guy needs to do his homework and install a PROPERLY sized HRV ( approx. $2,400 ) The fact is that every person expells over 5 gals. of moisture in the air per day, not including plants, animals , hot tubs ect. and you have to get rid of this execeve moisture. And for the record I am a certifed (Red Seal Journeyman Carpenter, HRAV certification, R2000, Water Furnace geo thermal service install, Taken courses in Heating and Ventilation Requirements of small Buildings and live in the Great white North were tems range are from 40+ to -40 so I witness to these sort of problems all the time.
I think my original post mentioned that the make up tube dumps cold air even when no fans, dryer etc. are exhuasting air. This would seem to indicate air loss somewhere else, but we can't find any other than the typical loss through windows and doors. I'm thinking maybe I do need an HRV or a dehumidifier contrary to Energy Wise. We didn't have a moisture issue prior to moving in. While we were working on the home I didn't notice any condensation on the windows. I had never heard of the 5 gallons of moisture before. That is a lot! We have been running a small dehumidifier every day and pulling out about 1-2 gal. per day. I can see why our humidity won't come down. Any thoughts on the high electric bill? The geo unit has been checked out by 2 different guys and appears to be running as designed but our electric bills are double what they should be.
65% humidity is way too high, especially in winter. You need to bring it down or you'll have structural damage. Either install some emergency ventillation or get about five more dehumidifiers.
Is it forced air heat or radiant? Any water pipes imbedded in the basement slab? Heated or unheated crawl?
A normal adult human might expell 1/4 to 1/2 gallon of water vapor per day, under normal circumstances. Significantly less in 65% humidity. Other human activities (cooking, showering, etc) will account for another 1/2 gallon or a gallon.
My guess is that you're still drawing a lot of moisture out of the concrete and drywall, though the possibility of something like a leak in your water service line should be considered. Evaporating the moisture will cost you on your heating bill, though it's hard to believe it would double it.
Have you checked your attic and crawlspace for "bypasses" that could be allowing air to escape?
Forced air geo, no pipes in slab ,heated crawl. Concrete has cured for over 1 year, drywall and paint at least 9 months. Water service is good. Crawlspace is tight ICFs, attic has r-50 cellulose, checked it with a heat gun, can't find any significant drops in temp. Someone else said 5gals. per day on personal water vapor output, maybe they meant.5?
Is the crawlspace floor covered with plastic?Yeah, to expell 5 gallons a day of moisture you'd have to drink at least five gallons a day. Not even Piffin drinks that much.
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
Any gas appliances?
A family of 5 produces a lot of laundry and dishes... have you checked the dryer?
Good point about the dryer.
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
I was also thinking.... dangerous...
You suspect the geothermal to be the source of you high electric bills. This would mean it's working twice as much as it should be, or designed to work. Since you have had 2 companies look at it, perhaps your electric usage is elsewhere.
i'm suspecting three things in part for each
Human expiration is one since you had no problem before moving in.
Another is that heat system, which I don't know all the ins and outs of, but I uspect some sort of a heat pump tecnology. That means there is a condensate drain line of of it. Where does it dump?
Third, you make no mention of a VB under the slabs or sealing the slabs. Unless you live in the dsert, you could be wicking water up from the ground. To test, get a few 24"square pieces of plastic and some duct tape. Tape it down on the crete for a few days then peel it up to see if there is moisture beaded up or wwet concrete under it.
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A heat pump won't produce condensation on the indoor coil when in heating mode (except perhaps briefly during the defrost cycle).
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
Like I said, I don't know how he has it set up. Geothermal could be air to air, water to air, water to water, water to air, or water to water to radiant. And the unit could be strangely placed, just like that air dump freezing the socks in his closet
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Residential geothermal would generally be water-to-freon and freon-to-air.
But I agree there seems to be something strange going on here.
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
Edited 2/7/2007 3:28 pm by DanH
What I find strange is the expected cost of heating a 2800 sq/ft house in an area that has 0-15 degree days at a total electric cost of $150-200 for a family of 5.
I live in a 2300 sq/ft house the only electric I use for heating is to turn a squirrel cage and my electric averages a tad under 100 bucks a month. Expecting to heat a 2800 sq/ft house for a little over a buck a day on the bottom side sounds miraculous.... is this possible?
Yeah, one thing I'd check is the lighting load. That could easily be $100/month if lots of lights are on and they're using incandescents everywhere.But geothermal is supposedly quite efficient if properly installed -- competitive with natural gas in most areas. So $150/month (over and above normal electric) for a "tight" house isn't unreasonable.
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
Edited 2/7/2007 4:39 pm by DanH
150 over and above normal I could understand...
Maybe I' misreading this...
" We should be paying about 150 -200 per month for our electric. This month it will be over twice that
Yeah, there are a number of things that don't compute. Our combined winter bills are probably about $180/month now, but we're probably better at conserving than most folks. (Though our house probably isn't as tight.)
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 dollar amount spent on electricity is meaningless.Rates vary way to much over the country.Proably by a factor 4 for regular rates. Then you have high rate discounts in someplace, high rate increases in other, special heating rates, time of day rates and it can be even more.Then you have have problems with people getting put on the wrong rating system.One thing that needs to be done is to get an acutal blower test done.The "energy" company clams that he will have enough natural ventalation, but no verification of this at all..
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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.
I will try to catch up on the questions raised since my last post.
-There is no gas to the house, all electric
-The dryer is venting properly to the outside of home
-We get a discounted rate from utility for being an all electric home
-The condensate line is pumped out the plumbing drain to septic
-Piffin I will try the plastic test on both basement and crawlspace floors. Basement has 1" rigid foam no vb, crawl has concrete only no vb . Never seen water in 1 1/2 yrs. since poured
-The heat system is a "pump n dump" Water is drawn from well, through geo unit and discharged directly to separate drain field . No radiant, rather forced air
-An energy analysis done on this home indicated an averageof $123 per month to heat/cool this home. When I wrote 150-200 that was an expectation for the winter heating months
-We are pretty concious of energy usage as far as lights, appliances etc. I have the utility coming to check my meter on Fri. and I may call my electrician to see what kind of loads I am pulling
"-An energy analysis done on this home indicated an averageof $123 per month to heat/cool this home. When I wrote 150-200 that was an expectation for the winter heating months"
That doesn't include hot water, drying clothes, dishwasher, cooking, dehumidifier. You electric bill doen't seem at all out of line for a family of 5.
Yeah, the dehumidifier is a fairly substantial load by itself (probably 5-10 amps), and presumably it's running continuously. The small dehumidifiers are fairly inefficient (though at least in the winter they're dumping the inefficiency as heat into the house, so it's not as much of a load).What kind of lighting do you have? Mostly incandescent? Three 60W bulbs lighting a bedroom is 180 watts, 54KWH if run 10 hours a day for a month. That's only about 5 dollars at current rates, but if you have 3-4 bedrooms, a living room, a family room, and a couple of hallways all lit up the same way you can be looking at $50-75 easy. Add in the 432KWH for a 5-amp dehumidifier -- that's another $35 right there.
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
I stopped using my clothes dryer unless I absolutely have to.
Do you have any idea how much it costs to cook your clothes? I'm single and was amazed at what 2 dryer loads a week was costing me when the sun would do it for free.
The best part of my electric bill that I really love is the 9 bucks a month I pay for the priviledge of being their customer. Who wouldn't like to bill all their customers $84 dollars a year just for being there if they need you.
Yes, BH makes a good point about varying rates around the country, but My bill is a good 125 just for lights, computers, TVs and appliances like refer, dryer, washer, DW, etc. It jumps up $40 when we have the kids doinglaundry and leaving a couple extra lights on at night...
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Scamp
It seems very inconsistent to me that a company with the knowledge to do an "energy analysis' would recommend you not install a mechanical ventilation system.
A properly constructed ICF house is much too tight to depend on either air leakage or simple exhaust fans to ventilate it.
Even wooden houses these days are too tight for that.
A HRV would control your indoor humidity, supply fresh clean air and not cost you a fortune in lost heat.
What is your thermostat set at? Does that temperature feel comfortable? Do you notice any effects of stale air like fatigue and malaise? Any mould smells or appearance of mildew?
Ron
Scamper,
"Crawlspace has concrete only, no vapor barrier." Not good. A lot of moisture can come through a concrete slab that lacks a vapor barrier. That's where you should perform the "tape down the plastic" test. You may have to install poly on top of your crawlspace slab -- not a pretty installation, but a possible fix for your dilemma.
Test in progress
How far is that leach field dump from your home? Any possibity at all that subsurface soil conditions can be leading that water back under your house? Is it uphill for instance and following trench made for dump line to it back down?Is that dollar estimate for energy only?Here, our bill is broiken down to so many cents per KWH and so much for delivery charges. Mione works out roughly 50/50. so if your eneergy estimate was only based on energy used and does not include delivery charges, that alone could explain the energy bill discrepancy
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I really don't think the drain field is an issue. It slopes away from home and we are in a sandy area with good drainage. The delivery charge factor was included in the analysis, but as I've been studying my bill, I see that my kwh rate is higher now by about 7% than when the original analysis was done. That would account for some of the total.
How do actual KW used compare to estimated on that early analysis and proposal?
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It would be hard to compare. The analysis gave a yearly expected total for heating and cooling. My utility bill is for total electric usage, not just the geo. We also don't have much of a history to go off of as we have only been in the home for about 7 weeks. Hard to establish an average as of yet.
I agree on blower door test. Also, perhaps revisit the original energy analysis and question what the inputs were (e.g. what were the assumed kwh costs, and as Pif noted, R-values for the envelope). I was recently twiddling around with HOT 2000 (or some later version of it), and noticed that many of the default parameters for energy costs were quite outdated (early 2000's). Energy costs have changed dramatically in the past few years, could be that $123/yr might have been reasonable 3-4 yrs ago, but certainly no longer. I'd update the energy analysis based on actual/as built values before pulling out much more hair on the cost issue. Moisture is another matter altogether.
You may be right, but given the expense of installing a geothermal heating system and the original poster complaining of a $300 electric bill in an area experiencing the weather he describes doesn't sound unusual to me at all. If his electric is so cheap I'd suggest ditch the geothermal and go electric baseboard with room thermostats.
Of course he could get every test in the book done on his house... but I'm not seeing a good reason why.
The geo wasn't that expensive to install- about 10% more than gas forced air and obviously should be more effecient than baseboard heat. More info- my first bill was $192. Not bad until you look at the fact that we only lived in the home for 12 days of the 28 day billing cycle. Prior to that we had the thermostat set at a constant 60 deg. warm enough to work in but not wasteful. We currently run our t stat at 68 during waking hours and 64 at night. Our projected bill for next month based on kwh used will put us over $400. Maybe that's cheap where your'e from, but to me it indicates something isn't right. Our previous house we averaged just over $100 per month electric with gas heat. That includes summer ac and the blower motor and a higher price per kwh. Same family, same lighting and appliance habits.
I get most of my moisture from the refrigerator running..
"The geo wasn't that expensive to install- about 10% more than gas forced air and obviously should be more effecient than baseboard heat."Why?geo is an energy source. baseboard heat is way of delivering energy.Too completely different things.BTW, you never said anything about my suggestion of doing a blower door test to see what exchange rate that you really have..
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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.
The poster said " ditch the geothermal and go with electric baseboards". Maybe I'm wrong, but I've never known baseboard heat to be considered as a more efficient heat source. People tear them out all the time in retrofit jobs and upgrade to something else. It doesn't mean they don't have their place and application, but I'm not going to tear out my new geothermal unit and replace it with baseboard heat. I'm having some issues with my hvac system and was looking for legitimate help here. I've found it from some and I appreciate that, but I don't need the sarcasm.
As for the blower door test, that is something we are considering if we can't figure this out soon.
Yeah, there's no way that electric baseboard is going to do better.But question: Is there "emergency" heat on this rig? If so, is it coming on very often?
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
Yes there is emergency strip heat on the unit. No it had never been on (I had purposefully left the breaker off) until we started having problems and ran some tests.
The best method to determine where your house is 'leaking' heat is to do a 'blower door' test. What this is is a special door installed with a blower mounted in it and you depressureize the house by sucking out air. You then go around with a smoke pencil (chemical smoke stick ) and look for rushing incomming air. Every R2000 / Energy label home built in Canada must have this test done. New building code states that every new home must have mechanical ventilation supplied to every habitable room min. CFM for differnt rooms i.e Bath , Bedroom , Living room . Most new HRV are over 75% efficient so you would recover 75% of your heat from exhaust air.And a side note, every appiance that moves more than 60 cfm , must have it's own make up air in the code.
I agree about the blower door test in general principle, but my instinct is that this willnot identify his probalem, if he has one. I am thinking that if there were indeed an air leak, that he would be venting that moisture out the same place and he would not have the moisture problem.So far, I think that his early energy analysis was simply wrong and he is going to need to mentally and financially reconcile that fact. The other problem of high RH is probably separate.Just a limited opinion so far based on limited facts.
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Evaporating all that moisture is consuming a non-trivial amount of heat. I don't know how one would figure out how much, though.Clearly the moisture problem needs to be fixed immediately. The other problem is "only money".
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
"I agree about the blower door test in general principle, but my instinct is that this willnot identify his probalem, if he has one."There are two different issues here that are somewhat related, maybe largely related.That is the high moisture readings and claim from the "energy consultant" that there would be enough natural leaks that it did not require controlled ventalion and HRV.Unless something was built wrong a house like this should require controlled ventalaltion.My guess is that he is not loosing too much heat from ventalation, but rather not getting enough air exchanges.And he is running the dehumidifiers to make up for that. And it is the dehumidifers that are running up the bills.5 amps/120 volts runing 24/7 would be about $40 for $10/kWh electric.One thing that no one mentioned was was the attic/roof construction was. We know all about what is below.But IIRC the attic/roof was not mentioned. Maybe that is the problem, he doesn't have one <G>.Myabe some IR testing would be in order also..
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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.
Edited 2/8/2007 11:02 am by BillHartmann
I think he said blown FG in the attic.You are probably on the right track with most of the other comments. The eneergy consultant seems to have been shooting fromthe hip without doing good work, IMO. Any house like this would need a recovery ventilation system.Meanwhile the windows should get openned.The mystery to me is where the moisture is coming from. It could be the house is just so tight that he needs to quit breathing, LOL
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Scamp,
A basic energy analysis is actually quite easy to do. Want to repeat it and see if my numbers match the original?
I would need:
The exterior and interior temperatures assumed for the purpose of the original analysis
The total area of ext wall above grade and its R-value (Most ICF systems are R25 and you get to add a bit for finishes and air films)
Same for ext wall below grade
Area of basement floor and its R-value
same for crawlspace floor
Area of window and door openings and R-value
Area of roof/ceiling that separates you from the outside or from unheated space and the R-value
And I think that's it.
It could be that the biggest flaw here, besides the lack of ventilation, is in the expectations you were fed.
Ron
Ah ha!Some ICFs "claim" to give performance matching R50. I never could figure that out. The elements that make it up total R-22 to R-26.That makes me wonder if they calculated this thing based on R-50 walls!
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Piffin,
You're probably right about those assumptions.
In terms of R-value, the only thing that really counts is the foam. Most monolithic wall ICF systems have a total of 5" of expanded polystyrene at R5/inch.
You know this stuff. You've worked with it too.
What the manufacturers are claiming is that the real-world performance of the ICF is the equivalent of R50 in conventional construction because of the effect of the thermal mass. Having lived in an ICF house for just over a year now, I would be pretty easy to convince that that is true.
I moved here from a wooden house of 2x6 construction 2/3 the size of this one and my heat cost is less than 1/3 of what it was before. There are other factors, too, but the ICF construction accounts for a large part of that difference.
Ron
I'm a fan of ICFs too. I can turn my chair right here and put my hand on an ICF wall and one of the crews is stacking blocks today.I just don't know how they quantify that R-50 rating. R-25 with no infiltration is pretty darn good. I think when copmparing to a FG batt 2x6 wall with its infiltration and convection loop factors, the effectives is probably twie as much...The whole insulation rating scheme for comparing accuratly is probably due for an overhaul, but that's another thread someday.
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Piffin
I haven't seen the R50 claims much lately and I'm always cruising our local distributors literature. (I'm what they call a block whore - I'll install any bloody thing at all for a price)
I completely agree with you that insulation rating just doesn't tell the whole story. It's an old and pretty near worn out tool.
I know my house performs way better then I ever expected. I regret putting money into radiant floors and a high efficiency boiler. The floors never get warm - the most you can say is that they aren't cold. I could have saved a thousand dollars by using a 17,000 BTU/hr water heater for a heat source instead of a fancy boiler but I was afraid it wouldn't be able to do the job.
Ron
I just had to review three different brands of ICF to decide which to use on this current project. At least one of the three used that phrase, effective performance of R-50" or language to that effect.
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If you have a fax, e-mail me you # and I will send you what I have
You can email ron privately from this thread by clicking on his name above his post, then choosing the email link in his profile. You woul d have to type it out in the form though because attachments cannot be sent through the board. After you two exchange notes once, though the rest is direct and you can send attachments directly to him.
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Scamp,
Sent you an email.
Ron
"Maybe I'm wrong, but I've never known baseboard heat to be considered as a more efficient heat source. "Baseboard heat is not just electric.There is also hydronic. And the hydronic heat can come from oil, gas, wood, coal, and ground source heatpumps. Even from electric boilers..
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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.
Yeah, but the post in question said "If his electric is so cheap I'd suggest ditch the geothermal and go electric baseboard with room thermostats."The only way that could save money is if the heat were turned off in a large part of the house.
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
He posted that trying to justify his and added the Electric part. And I looked back and he had it in other messages.This was the orignal message that was referering to."The geo wasn't that expensive to install- about 10% more than gas forced air and obviously should be more effecient than baseboard heat."http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=85311.30.
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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.
Please don't misquote me. Or assume what I am or am not trying to justify. Posting #25 (not my posting) refers to electric baseboard heat. I replied to that in posting #30 and omitted the word electric only because the original poster had already mentioned it. The subsequent message was a direct quote from posting # 25 attempting to clarify for you what had actually been written.
Also, I have mentioned at least twice what is in my attic/ceiling -r-50 blown cellulose. See postings 1 and 10
I think the net that's coming out here is that you're probably spending an extra $40-50 a month on that dehumidifier, but otherwise the electric numbers are probably in line.You need to get the humidity under control via ventillation. It's a hazard to both people and the structure.
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
I may be spending more currently, but my first bill was still higher than anticipated prior to ever running a dehumidifier. I am venting 24/7 right now and will probably end up with an hrv. Bits and pieces of this are starting to come together, but I still am scratching my head.
Maybe you should invest in a clamp-on ammeter. Something like the one on the right.
View Image
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 number one priority, as suggested is get the humidity under control. The heating of air at this level takes more energy. Once you get this under control, I am shure that your energy use will drop also. I would stat with the attic pipe, damper it or shut down completly or extend it up threw the roof and extend the bottom and put a u ' trap or within 1" of floor. I think you are pulling humidity accumulated in attic back into the house. Use Mechanical venting 24/7 till you see a dropin humidity.
I doubt that much humidity is being drawn from the attic. There's really no place for the moisture to come from in the attic, if the ceiling is reasonably tight.
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
I think the moisture and heat are rising up into the attic using the pipe as a chimney and when windows / doors and fans are used the moisture and cold are brought back down. I would bet there is condesation in attic and under the sheeting of the roof
But still the absolute humidity level in the attic would be necessarily less than in the house.
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 house has a relative humidity of 65% at 70 degrees F and the attic is at a lower temprature then the relative humidity will be greater % , and and at a point ( don't have my chart in front of me) will be 100% and will condense on all cold surfaces especially below freezing. Your not getting rid of the house humidity, just moving it around. The only way would be to extend the pipe out of the attic through the roof, like a chimney, but the energy cost would be high.
I agree that under worst-case conditions you could have condensation in the attic (though I would hope that standard building codes have been observed in regard to ventillation and they'd prevent this). But still you wouldn't be ADDing to the humidity in the house, even under these worst-case conditions. Moisture doesn't come from nowhere.
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
Moisture doesn't come from nowhere.
Exactly, Dan. Small example.
My house and nearby client house are similar construction/size. Both extremely tight, fixed glazing. Both have 2 adults and one small pet. Both kitchens are used. Both houses old enough to have fully dried.
We do .5 ACH. They have yet to hook up their (existing) air system. We have no rh problem (other than occasionally too low). They run a dehumidifier winters. I've pointed out it would be cheaper, and healthier, to complete the air system. Certainly they don't need the extra heat the dehumidifier puts out, given the passive heating/cooling both houses have.
There was a thread here a few weeks ago about a similar problem. OP experimented with cracking his window. Excessive rh went away, as did his respiratory problems. It's pretty simple. Fresh air is better. Consulting company that says otherwise (in a tight house) is negligent. PAHS Designer/Builder- Bury it!
Some updates. I believe energy consultant was probably wrong about not using an air exchanger. I've searched everywhere I can think of for moisture contributors and all I come up with is that the house is too tight not to have mechanical ventilation. If I run the bath fans all day and crack open a basement window the humidity will drop(slowly) about 2 % per day. I have plugged off the makeup air that runs to the attic and will install some form of mechanical ventilation directly into my ductwork.
Piffin- the taped down plastic showed no signs of moisture after three or four days. Still searching for answers to high electric bill. May be abnormal amp draw from something other than heat source. Certainly dehumidifier contributes but doesn't explain all the extra kwh. I appreciate everyone's input on this.
I think the dehumidifier may be a big part of it, but if you really want to sort out where the juice is going, buy yourself a clamp-on ammeter as illustrated earlier here.
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
Not hard for a dehumidifier to add forty bucks a month
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Kill-A-Watt is a device you plug your 120 v. appliance into. It measures and records current consumption over time. Mine showed me that a new refrigerator would pay for itself in under 4 years. After that, it's free, compared to my previous model. Ebay's a good source. Which is also where my client bought his so-far-unused air heat exchanger. I built mine from Popular Science plans.
I'd be suspicious of that dehumidifier. Test it, or better, eliminate it with fresh air. Then go about testing everything else. For 240 V., clamp on ammeter. The answer's there somewhere. You may find multiple problems.PAHS Designer/Builder- Bury it!
Most clamp-ons come with an adapter for 120V plugs.
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
You lost me.
Kill-A-Watt is far better to determine what's happening as it records current draw over time. Something like an appliance that turns itself on and off periodically, you want to know how much it draws/week or month. Unfortunately AFAIK it's only available for 120v.
For 240v., I have only my clamp-on. Works, but not the same way.PAHS Designer/Builder- Bury it!
a few thoughts that may be helpful- thermal mass does have a pretty strong effect. since 1980 we have lived in a passive solar earth sheltered house with concrete walls & floors insulated on the exterior with xps and heat 1800 sq ft with 2-3 cords in central mass. r value isnt the only relevant factor.
i recently had an energy analysis done & my combined kwh + delivery cost came out to 17 cents/kwh using National Grid [formerly mass electric] residential & no usage discounts are available. yours sounds low.
almost ALL icf & sips mfgrs REQUIRE the use of an hrv/erv.
i also had problems with energywise systems evaluation on a new icf house to be built this year, but wont go into that here. at my request they performed a do-over to the specs i wanted for no more $. they offer a guarantee if you install a meter dedicated to your hvac system and keep a monthly record for 12 months-did you pay for this? if not, maybe its not to late.
i agree with others that an erv/hrv will help eliminate the moisture, but also check your electric rate. good luck. frank
True. The clamp-on only gives you an instantaneous reading.
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
> geo is an energy source. baseboard heat is way of delivering energy.I took it that he was referring to geo vs resistance heating. Geo is almost always the winner.
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
There is a lot of information about geothermal at http://www.geoexchange.com/