Air Handler - Attic Vs. Utility Closet
Hello Everyone, I a new user to this site but I have been reading the forums for some time now. I am fairly new to the industry and am trying to learn as much and as fast as I can so I can help my dad out who owns his own AC company.
I am presented with a chanlange. My fatherinlaw is expanding his house from 1400 sq ft to 2800 sq ft.. Based on the heatload and the squarefootage he is going to need a second unit. He wants to take the exsiting air handler and move it from the utility closet into the attic along with the new system that is going to be installed. He wants to do this to open up more sq. ft. We live on the Gulf Coast and I am hearing that putting an air handler in the attic presents the following problems:
1. Creates mildew at a rapid rate
2. Enables the option to install high efficiency equipment
3. The unit turns into a rust bucket within years
4. Creates alot of condenstion in the system
Basically, I hear it is not a good idea and should be avoided if at all possible. If anyone has any feedback I would be more than happy to hear it.
air handlers and duct work in the attic is a really poor choice.
It means 30% bigger system needed for A/C and 30% higher cooling bills.
buy a copy of HVAC calc and run the numbers.
Is is possible your father-in-law would consider a sealed "conditioned" attic? That would quarantine the ductwork and air handler from the outside air. A lot of modern thinking says that has advantages when everything is considered. I live in S.Texas but about 90 minutes from the coast, am a homeowner so just asking questions not telling you what to do.
Duct leakage would become a very minor concern, from very major in an unconditioned attic. Heat gain thru ducts will go way down. Leakage between ceiling and attic becomes a non-issue. Sprayed in foam strengthens the roof allowing better protection from hurricane winds.
Best of luck -- Pstu
Duct loads add a significant amount to the heat load of the house. The best idea is to keep them in either a conditioned space or underneath the house if you have a crawl space.
Assuming no desire to change attic ductwork or attic insulation, my vote would go toward the closet air handler installation, every time. The paltry amount of square feet gained by putting the air handler up in the attic does not seem worth the trade off in either needing to upsize the equipment tonnage to overcome a performance loss (which leads to higher operating costs), or suffering the performance loss if the same equipment is moved up to the attic with no tonnage increase (which also leads to higher operating costs).
The existing air handler, if an upflow, may not work in the attic if it has to be laid horizontal to fit. Not every air handler out there is multi-directional. Mounting an upflow as an upflow in an attic location is somewhat silly, IMO. Condensate overflow with such an installation could take out the ceiling, since it's pretty tough to get a secondary drain pan underneath an upflow in an attic. You'd have to rely on a float switch instead, and hope it works should the primary drain plug up.
Installing air handlers in attics is just plain STUPID!!!!
I work in south Texas and many of the new homes have the air handler in the attic. This is just plain stupid to me for many reasons. If installed in the attic you open yourself up to to return air leaks sucking in 100+ degree heat that are usually around the air handler itself. If the main drain plugs up and it will you are depending on a secondary pan to catch the overflow in which many times it does not catch it all. If I have to service an a/c in the attic (aka) clean the coil, I as a contractor charge double for the service compared to if it is in the closet. I just plain hate dragging torches into a attic and have no sympathy for the customer when the bill is wrote up. Crawling up and over the duct work is difficult at times too and duct board is much better off if not disturbed. Is gaining a closet worth all the added problems inherited from an attic installation!!!!!!...I say NO WAY!!!
Last edited by kurt2022; 08-10-2008 at 12:21 PM.
I have to completly agree with that statement. The common sense question one needs to ask is, why do you want to stick a piece of equipment that cools/heats your home, in the hottest/coldest part of the house. Builders like to do that because they can claim X amount of square living/storage. It seems many houses I see, the HVAC system was the least thing planned for. A house needs to be designed for heating and cooling, and the airhandling equipment should always be in a conditioned space.
Originally Posted by kurt2022
HELL IS EMPTY AND ALL THE DEVILS ARE HERE.
Add one more vote for utility closet, but not necessarily the reason the other guys have said. Put it in the utility closet for your repair man's benefit. Why? Because he's not going to be happy about climbing through a dark, often difficult-to-navigate, 120F+ closet. He's going to be interested in one thing and one thing only -- getting the heck out of there.
Whereas, if the equipment's in an equipment closet, with room for the service tech to work, he's going to be a lot more focused on fixing the problem right than trying to get the heck out of the attic.
You're not "losing" all that much space if you do. My utility "closet" is < 9 sqft, probably less than 6sqft. Just add a bit of insulation to the walls surrounding it, make sure the ducts are (over)sized properly and you won't hear the unit either.
another vote for closet install vs attic install.
still..R-8 ductwork and mastic seal all ducts.
if you are still in design stage if you can put the
ductwork in the coniditoned space also it
is a great savings, and improved performance.
best of luck.
The cure of the part should not be attempted without the cure of the whole. ~Plato
With your return unducted through wall, door or platform sqaure footage lose is roughly 6 sq ft. If the return is ducted up into the attic from the closet the square footage is roughly 10 sq ft.
As Energy Rater said mastic seal the duct system and test for leakage because if your unit is in the interior with a non-ducted return it will be extremely easy for your home to be under negative pressure.
I hope they figured it out by now......