We recently had central AC installed (oh god, it's heaven after 23 years of Southern Ontario summers...), and I'm wondering if the AC unit is correctly sized for the house. The unit the company installed is a
3 ton Amana 14 SEER model, which is actually slightly oversized by the system they use. They recommend 1 ton per 1000 square feet, and the house is about 2500 square feet, not including the basement (and garage of course). The house is a bit weird. It's what they call a "great house" style nowadays, I think. Basically, almost the whole thing is one big room, and just the bedrooms and laundry room are actually distinct rooms with doors. I'm told this screws with air flow to the upstairs quite a bit because of the weird way they have to install ducts. I'm not sure if it would affect the choice of AC unit size.Anyhow, it obviously works, and the lack of humidity is great. I keep it set at 24C (75F) for the most part, which is a comfortable temperature, and it is able to maintain that even when it gets above
35C (95F) outside. However, if I set it below that, it struggles to maintain the temperature. For instance, today I tried setting it at 22C (72F) in the morning, and it was able to maintain that until late afternoon, when it went up to 24 even with the AC running full time. Outside temperature was 27.5C (82F). Another time, it was not running in the morning (tripped the breaker in an unrelated incident), and by the time we noticed, the temperature had gone up to around 27C. We reset the breaker and set it to 24, and even with it running full time, the temperature did not go down until the evening. On that day it was very hot outside, around 36C (97F). I called and asked the company that installed it about this stuff, and they claim it's normal and not to worry.Now, 24 is okay, and I am happy to leave it at that for the most part, but I'm getting the feeling the unit they installed is undersized for this house. I have friends who set their AC to 20C (68F) or 21C (70F), and it doesn't have any trouble maintaining that temperature on hot days. I know it's not good to have an oversized unit installed, but it's also not good to have an undersized unit running all the time to maintain the temperature.
I'd love to hear your thoughts on the subject. I'm not sure whether to just live with it or try to have the company install a larger unit (or even if it's actually required).
Chris