Installing central A/C in my 60s house.
I am not worry about the heat loss; my house has a radiant heating system.
The furnace heating capabilities would be just to speed up the heating process in the morning and as a back up.
The main task is a cooling system, where efficiency is not the key; the key is to have as much as comfortable air temperature, humidity control and the noise. The noise is the main factor.
A few techs came up with the 3.5T size for my 1600sqft split level in Chicago area. I was a bit suspicious about the size.
I have purchased software HVAC - Calc Residential, run the calculations, the result for 95F summer outside and 75F inside:
Total heat gain 30,200 BTUH, sensible 26,600, latent 3,600.
After reading on this site I put a system pieces together, planning to go with Infinity:
24ANA136 - A/C
The first thought was that the cooling capacity might be to big (24ANA1 is not available in 2.5T size), but if it is a hotter than 95F day and a few people visiting house and some kitchen, heat generation activities, the total heat gain goes up to 32,800 where the sensible heat gain portion is 28,300 BTUH. I was not be able to find any data on the sensible cooling capacity for 24ANA136, but I would assume that this size would not be too big.
The first stage of 24ANA136 has a cooling capacity of 25,800, what would perfectly benefit for the lower outside temperatures during the night and providing lower acoustical noise. This unit would also provide more precision temperature and humidity control.
I was originally going with the 2.5T Performance 24APA530, better matching size and lower noise system.
But the two stage 24ANA136, even over capacity a bit, would provide more flexible operation since it has a lower power 1st stage.
Now about the acoustical noise, since the noise is the key factor. It seems to me strange that the two stage Infinity 24ANA136 has a higher noise level than 24APA530. According to Carrier site it is 70dB and 68dB respectively. The product data sheet is showing a standard rating 73dB (high stage) and 68dB respectively. But the weighted sound level tables show that the typical octave band spectrum noise levels are actually lower by one or two dBs for the Infinity two stage A/C.
My question is, which unit is actually quieter?
My A/C most of the time would work only at a first stage.
Is this is considered good approach to design the system?
I need to place an order in a few days.
I would greatly appreciate for any advises, criticism or ideas.