Replacing both our AC units! Brand question.

[lewdog]

Originally Posted by Peter Gibbons

How did the estimators determine what size units were needed? Did they simply just offer to install the same size equipment that you already have or did they do a “manual J” calculation to calculate the required cooling loads? Did they inspect the ductwork and airflow at each register in every room? I would want to understand in detail how they arrived at your system sizing, ductwork modifications and the details of the coil and condenser SEER. Also, it’s good to understand what temp they are protecting for for max outdoor temperature in their calculations. When you ask these types of details from your estimators you will begin to get a good feel for how much science vs guessing each is doing.

I wasn't home for the quotes but my wife had some questions I asked her to discuss.

SEER rating doesn't mean much in Phoenix since the humidity is so low. It's basically useless here and I do know that. Both of these installers gave us quotes for 14 and 16 SEER units and both actually recommended the 14 SEER units given how much solar power we generate. Based on my research I knew this was true, so I was impressed neither tried to up sell me on a higher SEER like another company tried to do.

I know the Carrier quote the guy just matched the current system size. The Lennox quote came from looking at our duct work, vents and how the house currently cools (our master bedroom and one of the front bedrooms have never cooled as well as other rooms) and he recommended we bump up each unit .5 tons to a 3 and 4 instead of the current 2.5 and 3.5.