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I own a rental townhouse with a HVAC functioning unit. 1200 sq ft, 2T - 13 seer.
Tenants are complaining lately (July) that the house stays between 76-78 even though thermostat set at 65. Outside temps in Dallas have been running about 100 degrees.
I've had had the coils cleaned and condenser unit serviced and refrigerent levels checked. Tenant says not enough improvement (they can get it to 76 now vs. 78)
My AC guy says other options are new 2.5 T system, more insultation in attic, an attic fan.
In the meantime, I've provided 2 portables so we are coasting with that but tenants expect a permanent solution.
Part of me thinks 78 should be ok when its 100+ outside. But I want happy tenants.
Do you really think more insulation would make a significant diff? Attic fan? Would you get a whole new system (mine is from 2003)?? There were no issues in the winter with heat.
Buy them a window unit if they want it to be that cold. It's unrealistic to expect it to be 65 inside when it's 100 outside. That central ac won't last long with them using it like that.
A good attic fan probably wouldn't hurt though, it'll reduce the heat transferring through the ceiling.
2.5 is most likely too big for a 1200 sq ft place. You don't want an oversized unit or you're going to have mold issues. The only way to know if it's properly sized is for the ac tech to do a manual j load calculation.
I'd say insulation in the attic as well as adding insulation to existing walls is your best option. Especially if the insulation is lacking right now.
Insulation is ABSOLUTELY the smart thing to do! It almost certainly makes sense to also have the entire structure checked for AIR LEAKS, even if it is technically part of an HOA there is no reason for you not to make your unit more "energy tight" for lower electric bills, better comfort, and more durability. The thing is that depending on when your unit was built there may not have been standards / knowledge about just how important weather sealing is -- from little things like can lights that can let a shocking amount of hot air seep from the attic into the living space, to issue with the attic ventilation that can literally accelerate the detioration of structures 10x or more, to things like improperly sealed ductwork the data shows all but a handful of really knowledge, careful builders have been responsible for homeowners wasting huge amounts of money in poorly sealed structures. There are now good results from studies that show radiant barriers can cut one's cooling costs by 10% -- Radiant Barriers | Department of Energy
It NEVER makes sense to get an oversized HVAC unit, the negative effects associated with such units include insufficient dehumidification and increased wear & tear on the starting load -- Why an Oversized Air Conditioner Is a Bad Idea
Finally I would caution that though you will find randomn goofs on the interwebs trying to make an arguement that becuase the max amps of window units is typically quite low they are somehow 'saving you money' those boneheads fail to recognize that the compressors in whole house HVAC units are mostly loafing while running at 240v and modern multi-speed units are orders of magnitude more capable than the pathetic little things furiously burning watts in window units but in actual practice folks switch off the noisy little buggers as they otherwise could not get any sleep... Window-Mounted Air Conditioners Save Energy ?| GreenBuildingAdvisor.com
Sounds like the unit is doing just fine. Temp here outside is 93 and inside temp is right about 76-78 and perfectly comfortable. Setting the stat to 65 simply insures it stays on continuously.
Attic insulation is generally the best bang for the buck (skip the fans), but if there is an outside wall in direct sunlight that could be radiating heat into the rooms and making it feel warmer than the air temp. In a townhouse, there could be some heat transfer from a vacant unit, depending on how the townhouses were constructed.
"There are now good results from studies that show radiant barriers can cut one's cooling costs by 10% -- Radiant Barriers | Department of Energy"
Chet, remember we had a recent discussion on how these may be a source of ignition in home fires during electrical storms. I'd stick with standard insulation until that issue has been explored and resolved. Most of the time they may be fine, but the data is troubling.
FWIW, some of us who are sensitive to extraneous sounds sleep better with a white noise machine or window ac. Also, as your article notes, my little window AC in the bedroom cools a small space instead of the entire house, so the 10% loss is a drop in the bucket. If the real issue in the townhouse is an upstairs bedroom being too hot, I would consider a window unit or other small unit as a possibility.
See if your electric company does energy audits. They are free here. We live in Texas where it's routinely 100+. We have no problem maintaining 75-76 degrees (and our thermostat is set at 76). So I would think there is something to cause the a/c to not run efficiently.
If they're setting it to 65 and it is only reaching 76 there's a problem. When was the last time you had the temp control box checked/replaced? You could need a part that'll cost about $200 and the problem could be solved.
Where is the air handler, and ducts? If they are in the attic, check the ducts for leaks and make sure they are properly insulated.
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