On Monday, September 18, 2017 at 12:27:05 PM UTC-4, Uncle Monster wrote:
On Sunday, September 17, 2017 at 11:24:31 AM UTC-5, wrote:
The question was about short cycling and how he could determine if his was short cycling. Most of the posts here were about what temp is comfortable and other useless information. I love the "wrong again" comment. That was also helpful especially without a reason. I'm pretty sure my one year old, 7K, 2.5 ton system is too big for my 720 square foot house. I had the compressor and outdoor components exchanged for 2 ton components within two weeks. The humidity is always in the upper fifties so it never feels good. Another sign it's too big. Not surprisingly, the blower motor went out at 12 months. I was lead to believe it was a manufacturing problem. Doesn't take a genious to figure out a system turning off and on too often will also cause wear and tear. Which leads us back to the original question....how short is too short? It was hot here in Chicago yesterday, 85, and my newly repaired A/C was on 7 minutes and off 7 minutes which I felt was too short. Still at a loss given the info here. It was hot, am I wrong in thinking it was too short? BTW, I realize insulation, window and door leaks must factor in. Four years ago I had 8 inches of insulation blown the attic. My old two ton A/C never had such short cycles, not even with 4 inches of insulation. I understand on a hot day 10 minutes on and 10 minutes off or three cycles an hour could be appropriate from info I got elsewhere. Anyone agree? Comments? I can't replace worn out parts every year.


I've a question for you. The size of your AC unit seems to be too big for your small well insulated house, did the HVAC contractor do any calculations or take into account the energy saving measures you have taken? I've a few more questions I'm formulating since one of the things I did when I was still working was HVAC system installation and repair. ヽ(ヅ)ノ

[8~{} Uncle AC Monster


I saw her say that they put in a new 2.5 ton, then swapped it out two
weeks later for 2 ton. But I missed that the place is only 750 sq ft!
That's like three 20 x 12 rooms. We don't know the rest of the situation,
but I agree, it sure seems oversized, still, to me. 2.5 tons is 30K BTUs.
It's like having a 10K BTU unit in each room. Would you buy a 10K
unit for that size room? Even more remarkable is that
they had a 2.5 in there, knew that was too big, but then only went down
to 2.0? It's probably useable with that size if she gets the short
cycling fixed, but it's most likely not optimum either.

What was in there before they put the new 2.5 ton in? What was the
experience with the old unit?