what makes a good hvac installation
everything i’ve read on hvac installation says a properly installed unit is more important than any paticular brand. well i’m doing the duct work now ,what should i do to make this as good as possible. on the forced air 125k furnace/5 ton central air i don’t see much to do extra as far as hooking up ,gas,elec, flue. pretty straight forward.on the duct work i have two 4″ return filters on each side going out to 3 -8×30 grilles (i know it would be better to have a return in each room but this is a old house+ addition and i’m doing good to get supply ducts to each room). supply side, lots of ducts (17 total) some 6 and some 8″ as the runs come to the outlets ,i hook up about 1′ flex for sound. trying to tape all the joints etc. any other ideas to make this a pretty decent system. i’m in pretty much unkown territory here. thanks larry
Edited 6/10/2004 12:36 am ET by always overbudget
Replies
I don't have any experience with an HVAC installation but I have researched ways to make my existing system more efficient and the one thing I have seen mentioned which I have yet to do is to use some sort of mastic for the joints. I think thats what they call it. Duct tape has a multitude of uses but is not very effective at sealing ducts according to things I have read. Whether this is true or not I don't know. Hopefully one of the pros will chime in on this. The mastic idea does make sense to me though in that you would end up with more of a continuous monolithic run of duct with little potential for air escape.
You got all of that right....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming.... WOW!!! What a Ride!
The mastic idea does make sense
IIRC, a brand name is Duc-Seal. Premixed & water clean up if still wet. Goes on the outside of made-up joints in metal ductwork. You then insulate, and the blankets use the recommended sealing tape (which is usually an aluminum tape. This gets a tad tricky where you change over to flex. But survivable. Occupational hazard of my occupation not being around (sorry Bubba)
two 4" return filters on
what does that mean?
5 ton unit needs a lot of return air filter area
probably wild guess
800 in sq or more
i didn't state that right, i have 2- 20x24" 4" thick filters one on each side with 2 seperate return plenuims. thanks larry
there is a recommended amount of filter are per ton but i can not remember it
my 3/12 ton unit has a 20x30 filter (600 in2) and it works ok but does not meet the spec of the ac manufacturer
where i live south carolina there is never return air in each room
even on mega buck homes
one or twocentral plenums
Ditto to the mastic.
FHB has a fair article on HVAC in the last issue, that may help you.
Dave
whats missing in the HVAc world is info on which units are more durable.
Consumer reports has done some surveys on central air, they reported the results as rheem/ruud and trane near the top.
carrier middle
goodman on bottom
I had heard (from BIL-- don't go there) Carrier and Trane were put together in the same factory?
Per my HVAC guy, Lennox is the best, and priced accordingly. He agrees that Goodman is the worst.
So-called duct tape isn't for ducts at all, it's for all those other temporary uses. There's good aluminum foil tape, $13/50 yds, that does seal and last long enough for duct work. Got some yesterday at a little HVAC supply place.
-- J.S.
John,
"Per my HVAC guy, Lennox is the best, and priced accordingly. He agrees that Goodman is the worst."
Take this for what it's worth, but your "HVAC guy" is completely misinformed or intentionally lying to you. Either case would be reason to look elsewhere.
I have heard that lennox units are good maybe above average.
i have also heard that many of the parts are lennox only and obtainable thru lennox only
which the lennox dealers like
Edited 7/1/2004 7:18 am ET by wain
Lennox (and Carrier, Bryant and Trane) spend a lot of money on national advertising campaigns and the prices they charge have nothing to do with quality or availablilty. They have to recover the millions spent on advertising.
If you were to look at the details of construction and warranty offered by Lennox (and all the 'premium' mfgrs) you would see that they are average, no better. A Lennox dealer will tell you otherwise. Same goes for Carrier and Trane and York and Heil, et al.
I'm talking about residential products, i.e. gas furnaces and air conditioners. Commercial and custom equipment is a different industry.
Compare apples to apples, look at warranties offered and standardized performance ratings. The facts are independent of biases and advertising and allegiances.
i see you mention "heil" how are they? looking at them i don't see any big neg. or pluses,but every salesman will tell you his is the best.the heil brand come in at a good price and warranty as good as anyone else. larry
I have the top-of-the line Heil installed in my home. Only had it for 1-1/2 years, though. I have no complaints, but I got it as a special incentive by the manufacturer to Engineers in the HVAC industry. Price a 125 MBH, variable speed, 2 stage, 94% furnace. The list is about $2800. That is more than I paid, installed.
that makes me feel better as that is the same furnace i bought,size and everything plus a 80% 2 stage for the 2nd floor. around here there really are no heil dealers,but i'm not to worried about that as most small parts are pretty much universal. thanks larry
be careful about the hvac-talk folks.
-they do not like any Do it yourself people. (even though they probably work on all their own stuff rather than calling the Maytag repair man or Evinrude man , etc other professional). Even simple stuff like replacing a circuit breaker is in their opinion a life threatening evolution that can ONLY be done by an HVAC pro. Don't think of putting on a new condenser fan blade - too dangerous. It might fly off and hit you.
- they claim ALL brands are the same the only difference is the installation !!!!!!!!!!! Do you know any other products where all brands are exactly the same?
- even tho ALL brands are the same, just by chance the brand they happen to sell is the best brand for you (isn't that special!!) . I bet Even tho deep in their heart maybe there is another better brand, but they can not become a dealer for whatever reason.
they also forbid ANY mention of that dirty word "price". Even though most of us are adult enought to recognise that job cost might actually vary with brand, job scope, and location in the US
they will not let price be mentioned+++++
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Consumer reports is a central A/C survey not gas heaters (nothing wrong with that) - the surprise to me was how poorly Carrier/bryant scored - they have had bad indoor coils in last 10 years- my mom and two neighbors have had indoor coils fail at 8 years - dealer then sez "well you really should replace the whole thing!!!!!$$$$$$$$$$$$$
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i think the best are still Trane/amer standard (both more money) and heil and rheem (middle of the pack in price)
Goodman is getting better fast- but lots of part time people install them - they rated on the bottom in the CR surveys (of a few million reader)probably because of a variety of installers and more hacks/part time people
Edited 7/7/2004 8:20 am ET by wain
i think you hit that nail on the head and drove it with one hit! i'm not sure there is another trade out there that feels like they are building a space shuttle and no one else could possibly be compenent enough to do the job. so you hire them to do a install and they send out 2 19 year olds making 7.00 hr to throw a unit in and get gone.and all of a sudden the space shuttle doesn't look so complicated . larry
OK then, so what is the best make?
-- J.S.
Currently, I don't think there is a "bad" furnace made. It comes down to proper sizing, and installation, and proper servicing. Warranty and after sale service availability is often the overlooked factor.
where price is a factor (and it's always a factor with me) I go with Goodman units for my shopping center spaces I usually use 5ton gas pacs that i pay about $1500 for i have some goodman stuff thats been running for over 15years that i've never done more than clean the coils on... fact of the matter... i've never replaced a part on any of em... I use their split unuts also... same deal... never a problem... I have taken apart some high end units and you can tell a difference in the parts and ease at which you can service em...... but all in all you are talk'n a coil... a compressor... a fan motor...a magnetic contactor... and a time delay... and a start capacitor... there is not alot more to most units... they add some controls and some boards... the fan motors and compressors all seem to come from the 2 or 3 manufacters... so i have to guess the reat is mostly hype...
short duct runs of the proper size with few bends... seal all your joints... you can never oversize your return.. or your filter area... I've heard all the stories about balancing and people who don't know what they are doing always oversize units ect... well i always oversize if i can... the perfect world doesn't see bad insulation... doors held open... exhaust fans that are never turned off.... ect... better to regret an extra $200 for the bigger unit and never need it than wish you had it...
pony
Not necessarily the make but the compressor for AC and HP, no clue about natural gas stuff. .
Have installed Goodman, Rheem, and Carrier heat pumps. The Rheem and Goodman had Copeland scroll compressors and both performed well, both 4 T, the Goodman is actually slightly quieter (fan) than the Rheem. The newer Goodman air handler has variable speed GE electronic motor, very quiet and balanced squirrel cage. That said, the Goodman cabinets really are cheap, the last one I put in had to add 5 homemade brackets (just 1/2 conduit with flattened and drilled ends) to stiffen the cabinet. Have looked at York and their cabinets are much better, but not much difference in the guts. I can afford the time to make 5 brackets for the $1K cost differential.
Take a look at HVAC-talk.com, the "best" are usually what the hvac guy makes the most profit on or is a dealer for.
The consumer report 'findings' were not them buying and testing units, simply a survey of readers. Given CR readership dependence on others to tell them what to buy, don't hold much credibility in a survey like that, plus, phsycology stuies show that people who pay more than they later found out what they bought was worth delude themselves into thinking they got a good deal and tend to rate the higher price stuff better - look a tools section here for numerous examples of that.
No such thing. What is the best car? Matter of opinion. Lots of good ones. The design, layout and installation, if done well, will make the poorest equipment perform well, when done poorly, will make the best equipment perform poorly.
Each manufacturer makes cheap equipment. Most manufacturers also make a "better" and "best" version. Fact is, regardless of the dozens of brands, there are 6 major manufacturers of residential HVAC equipment in this country. None of them offer a superior line.
I've heard the same thing--duct tape bad, aluminum tape good.
If a installer has to rely on ANY kind of duct tape , He would be best to improve his joint making practices, because if a joint is made PROPERLY, duct tape should not be required at all. Some sloppy installers use it to "hide" their bad work. Hube
Some sloppy installers use it to "hide" their bad work
True enough. What scares me is the work "hidden" under the insulating blankets on the ducts (the only place I want to see tape is on the blanket joints).Occupational hazard of my occupation not being around (sorry Bubba)
Rating equipment in HVAC is really tough. My experience has led me to believe that installation and design may weigh in as more of a factor in many cases, i.e. good equipment with poor installation and design not be any better than mid line equipment and good design/install.
That is the main thrust of the article in FHB. My own research and experience pretty well leads me to the same conclusion.
Dave
...properly installed....(i know it would be better to have a return in each room ...
you answer your own question - - seal the ducts for sure, but that won't make up for sub-par design - - Dave R has it just right...
AOB,
Do what you have to to get more returns installed. 3 at 30 X 8 is not enough for a 5 ton system. Depending on the actual return ductwork, you may get by with 4.
However, if you know that you need returns in each space, but are unwilling to install them, I would make the following suggestions:
get help, or
get warmer clothes.
Tim
now before i start let me clarify i don't know nutin about this just what i read. but if i remember right my code book said i need 6 sq " per 1000 btu. i've got a 5 ton unit = 60,000= 360 sq ". my return duct is 8x30x3 =720 sq inch. what am i missing here? am i figuring this wrong? i could probably get another return duct run with a 8- 10 round duct over to another room, do you think i need that much air? i do understand if i choke the return nothing else is going to be right. thanks larry
A 30X8 return grille, at 500 fpm is good for about 550 cfm. That's how I would size a return grille. What you're missing is that the grille has a free are that is significantly less than the nominal size.
Return duct should be sized at 0.04 - 0.05 inches of static pressure loss per 100ft or no greater than 500 fpm.
For a 5 ton unit operating in cooling mode, at say 1950 cfm, simple math will give you 1950/500=3.9 sq ft of duct.
You asked "What makes a good installation?" Knowing that you need a return in every room is a good start. Ignoring that fact is a bad start.
I have a 5 ton system in my home and although I do not have a return in every room, there are 10 separate return grilles/registers installed.
Two things to consider as you lay-out the system. 1-How do you want the air to move and 2-How much air do you need.
Tim