I'm building a new 2 1/2 story house. I would like to put the HVAC equipment in closets on the 1st and 2nd floors, but our designer is pushing us to just stick 'em in the attic.
My rationale is that the attic installations tend to take up a lot of floorspace that I'd rather use for storage or something useful on the
3rd floor. Also, there might be some gain in efficiency with shorter duct runs and having the equipment operating inside the conditioned space.
So, what do you all think? Would you rather install/maintain equipment in a dedicated closet, or a hot attic? How big a closet would you like to see for this? I'd like to make it as easy as possible to work on. Any other words of wisdom? :-)
Tell the designers that they can put them in the closets or they can look for another job. If they persist with their ignorance, drag them up into a hot attic and make them knee crawl, through all the fiberglass insulation, to the other side of the house where the air handler got put, then ask them if they are going to do a complete service on the unit?? and are they going to be willing to crawl up in the attic when its 100 degrees outside, on the
4th of July to replace a transformer, because the homeowner cut and shorted out the condenser control wire with a weed wacker.
think accessability for service, maintenance, and repairs.
Put the air handlers in closets, make them big enough so that you have a
*MINIMUM* of 6 inches clearance on both sides, 1 inch on the back and 8-12 inches on the front behind the door if its all electric, and 12 - 16 inches on the front if its a gas furnace. Do check your local codes and the manufacturers instructions for the exact *MINIMUM* requirements. Ita always a real good idea to leave a little extra room, and make the access door frame a couple of inches wider than the unit to allow for replacement down the road.
yeah, well just wait until its time to replace it.
how many times have we seen a furnace in an attic that the only way to get it out and a new one in is to cut a hole in the roof. Or when there's a condensate drain issue and water backs up, overflows, and ruins sheet rock ceilings.
Thank you for your comments. They are quite helpful, and I agree 100%. I haven't spec'd equipment yet, so don't know the exact sizes, but was looking at doing a 4x5 foot closet, which should provide at least as much clearance as above.
There are three issues brought up by our designer for why he prefers the attic:
Lost floorspace in the living area - I can live with that.
Noise - I think I can live with that.
Zone dampers. Where to put them.? In a closet installation, all the ductwork will be concealed in soffits and ceilings, so where do you put the zone dampers where they will be accessible. I don't quite know how to address this one.
In addition, since all the ductwork will be inaccessible, I'm pushing for all metal ductwork instead of flex. I think this may also be causing our designer some heartburn, as he has to be a bit more careful to leave space to route it.
Around here (Houston, Texas) pretty much all the installs I've seen look like the "giant silver octopus," which is to say the air handler is smack dab in the middle of the attic, with a tiny plenum, and miles of flex duct running every-which-way from it.
OK... that works... however 4x5ft is a bit of overkill
He's getting paid by the sqft.....it cuts into his bottom line
If the system is correctly designed and sized, it should be almost virtualy silent
Each system will be its own zone... unless you have less than about 800 sqft, or more than about 2500 sqft or so per floor, zone dampers shouldn't be an issue.
Get the correctly designed and sized tin ductwork....when done right, it will last the life of the house and is a 1 time expense, where flex *WILL* have to be replaced repeatedly over the life of the house.
You sure can... cause if it's done right, it won't matter where it's at... as you won't hear it anyway.
They can be in the closet. Or you can still run the ducting in the attic and put them up there. Dampers don't require a lot of maintenance, so it's not that big of an issue.
I would REQUEST metal... PERIOD!
That's tuff shit... that's why he is a designer... it's his job.
Mine is in the attic and it's not bad. If the roof is a high pitch, the attic is floored, and there are decent stairs then the attic is no big deal. So it really depends on your attic.
That's good to know. I won't push to make them any bigger than that, which should make our designer happy.
Our floors will be, I think, in the 2000-2500 sqft range. So, you're saying that, at that size, there's not much benefit in zoning within a given floor? I can see that, I suppose. I was thinking that some zoning might be nice for convenience/comfort, though. So, for example, the kitchen could get extra air when it's hot in there, without freezing the rest of the floor. (A problem we have now.) Is that worth doing, and if so, back to the original question...where to put the dampers?
I'm going to push for that. Finding a company willing to do it that way may be a challenge around here (Houston), these days, sad to say.
Well, I'd rather not run the ducting all the way up to the attic, and back down. In the closet would be good, if there's a convenient place to branch off there. Otherwise, I guess I'm looking at access panels in closets or something like that. Is that doable?
I hope they don't need much maintenance, but since they're electrical AND mechanical ... well, sooner or later!
Dampers usually go on the main trunk lines. FWIW, with a correctly installed system with properly sized and designed equipment and ductwork, there should be no more than a degree or so temp diference between any 2 rooms....including the kitchen. Keep in mind that the kitchen needs to have proper supply and exhaust ventilation, as well as utility room(s). Think about having an ERV or 2 installed.
They are out there, its just a matter of finding one... and no, they will not be the lowest bidder.
have you did any research whatsoever on zoning? One very important facet to remember is for the most part, residential hvac systems are constant volume Oh sure, they may have a variable speed blower, but they're moving a fixed cfm thru the coils. Now along comes a zoning damper that closes and what happens to the air that was going thru the coil and down that duct? Where does the extra air go? Well, some systems would then have a bypass damper, such that the air you just paid to be cooled is now dumped right back into the return air. Now you pay to cool it again. Pretty soon the supply air temp sensor says Hey, I'm too cold & therefore it will cycle the compressor off so the coil doesnt freeze.
Cheaper zoning systems have dampers that are either open or closed, far better systems have dampers that modulate from 0%-100%. Another critical factor is upsizing the branch ducts to accomodate the extra airflows imposed when zone dampers modulate closed. Then there's the bypass system. Cheap, barometic control or modulating motorized control. Does your zoning system have communicating thermostats & is it web-enabled?
Regarding the tin ductwork: I'm in Ca and easily 95% of ALL homes in Ca have flex duct installed in them, even brand new homes. I'll venture a guess that you will not find a resi hvac contractor in Houston that installs metal ducts in attics or in new resi, unless its a custom home. Sealing sheet metal when its crammed into tight soffit areas etc just isnt going to happen. I'd rather have a tight flex duct system than a leaky tin system anyday.
Another form of sheet metal is the insulated aluma-flex duct. This stuff is great, as long as you dont have to trim to fit or dont squash it. It's very easily damaged, and no way to re-straighten it. Personally I think you're far better off with R8, mylar jacketed flex duct. Pricier than R4.2, but for mor energy efficient as well.
On custom homes we almost always zone the master suite from th erest of the second floor, and the main living area (kitchen, family room, and entry from th erest of the first) Seperate trunkline for each zone!
I hate Flex, and will not use more than 6' at any one time, properly installed it will not need to be replaced, but we are one of those crazy resi company's that use all metal except for returns and connectors
Are they still selling 4.2, I thought it all went to 6 and 8!
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