Hi all. I have a 2 storey, ~1200 sq ft home in a hot climate. I have a single HVAC unit…central air and ductwork, electric AC/heat. There is no zoning to the system. The thermostat is downstairs.
Everything is great in the winter months. But in the summer months, the upstairs is absolutely stifling. I don’t have a thermostat upstairs, but it feels like it stays at least 10 degrees hotter than downstairs. I get that hot air rises, but considering the bedrooms are upstairs, it makes things unbearable.
My HVAC air handler and condenser are from 2008, so they are rather old and I’m likely to have to replace them soon. When I do so, I want to figure out how to keep the upstairs more comfortable.
Before I start asking companies for quotes, I want to figure out what I’m doing first. Some things I’ve come across…
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Install something like a Nest system with a remote temperature sensor. Place the temperature sensor upstairs and have the Nest use that to figure out when to cycle the AC on instead of the downstairs thermostat. I could install something like this myself instead of needing an HVAC company, though it isn’t necessary very efficient.
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Consult with an HVAC company about having dampers/a zoning system installed. From what I’ve read online, it seems like people are saying this isn’t really financially worth it. But if I’m at the point where I want a new system anyway, would it make sense?
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Window AC units are an obvious “solution”, but I can’t have them due to the HOA.
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I have read of suggestions of people saying to close the vents downstairs in the summer, but it seems like this is bad advice, as supposedly it will stress your HVAC and cause it to fail prematurely.
Edit: Just found a new one…setting the fan on the thermostat to “on” instead of “auto”. Although some people seem to warn of mold growth.
Would love to hear any and all suggestions. Thanks!
Just had to solve this problem myself recently. Same issue, upstairs stifling while downstairs stays nice and cool. For a whole year I just ran the system a bit colder, but that made the downstairs freezing in order to make the upstairs feel normal. Not to mention all of the energy waste running the system for so long, my home is 2300 ft.² so I went for the dual zone with a mechanized damper. You could save on the cost by installing a manual damper that you could adjust as needed so far the system marks very well and my upstairs can get nice and cold, while the downstairs is a cozy warm temperature. I paid an HVAC company $2,300 for this to be done, but the manual damper would have been just $600.
Other options I considered though were going to mini split route like the other comments suggest, or if your HOA is strict about even that, you could even use an indoor AC or two, and have the exhaust vents blowing out the window.
Yeah, these also work pretty well, OP. Just make sure you get the ones with two hoses, not just one for exhaust. The single hose ones create a vacuum in your house that sucks in outside air making them significantly less efficient.
Oh dang I didn’t even know there was a two hose type. It makes sense though since it would be sucking the room air through to exhaust outside, creating a vacuum
Jeez at 2,300 feet you should have two central airs already or a vastly optimized system that should have handled that. That’s shitty code or builder unfortunately.
Home was built in 1997 so maybe things were different! I certainly wouldn’t mind another central air unit or heat pump