Heating, Air Conditioning, Fridge, HVAC/Differing Temperatures


I live in a warm valley of southern California. We just moved into a new 2-story home built in 2005. I assume the house is fairly energy efficient already given the newer construction. However, there is only a single A/C unit for the whole house, and the thermostat is located downstairs. Where this becomes a problem is when warm weather hits, the upstairs is at least 8 degrees warmer than the downstairs. However, since the thermostat is located downstairs and it reads off of that temperature, we would have to make it freezing downstairs in order for the upstairs to be comfortable. I am trying to figure out what I can do to resolve this problem, short of installing an entirely separate A/C unit outside dedicated for the upstairs. That would be just too expensive for us.

Do you have any suggestions on fixes for this problem? I was wondering if it is possible to keep just the single A/C unit already installed but have a separate thermostat installed upstairs? In essence, it would act as a split A/C while utilizing just one A/C unit. Is this possible? If so, is this costly to have done? I appreciate your time and feedback on this. Thank-you.

Your problem is airflow imbalance: The first floor receives more air than it should, and the second floor receives less. You need to throttle the first floor branch duct "volume dampers" (if there are any, and if they're accessible) to force more air to the second floor. Click on "Balancing" at the website. Do be careful of the "TD" (Home page) so as not to damage the compressor.

You could zone the second floor separately, but it'd probably require ductwork modifications. Click on "Zoning".

Let me know if you need more.


Heating, Air Conditioning, Fridge, HVAC

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Fred Weldin


I can't help you if your whatsis won't work, people (Especially if it's a refrigerator); I have no experience with appliances, and I haven't been involved with H&AC service and repair since March 08, 1996 (Thank the Lord); I always send a "standard" reply to appliance questions and H&AC "Service and Repair" questions (about 20 a month), so if you want to know why your whatsis isn't working like it used to, ask someone else. A lot of my answers arenít read by the questioners; in that event, I always send reminders to read the answers for a month or more (the word "idiots" comes to mind - actually there's another more appropriate word, but discretion prevents its use here). If you have questions about how big a unit you need, if one room's warmer than the others, if you want an opinion oas to scope of work on bids received, etc. just ask. Do visit www.askweldin.com, there's a lot of good information on sizing, ductwork, efficiency, as well as some techniques accomplished DIY-ers can use to troubleshoot and improve their H&AC. Finally, I want to thank all of the kind, serious people whom I meet here: I enjoy working with you. My wife says I'm "snarky" from time to time; as for you others, please use your imagination as to the responses swirling on the snarky side of my brain when I read your questions.


53 years in the business. See www.askweldin.com


B of ME U of D 1965, numerous classes, seminars and a lot of "Hands On" learning since.

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