I want to confirm the house is 4800 sq. ft. and the basement is 1800 sq. ft. The area of the first and second floor are about equal. Is this correct?

Here are my comments:

1)You want to verify they will be installing a Carrier coil. Sometimes a contractor will want to use a third party coil to save money. I suggest getting a 4 inch media filter. They perform much better than 1 inch filters. You want a true 2-stage thermostat. The Carrier Edge series should be OK. I think this equipment is compatible with the Infinity series thermostat if you want something better. If you really want to control the temperature of the basement in the winter, then you should have a thermostat in the basement with zone control. The Infinity zoning system is considered one of the best.

2) Find out the history of the HVAC contractor. I would feel much better if he were a Carrier factory authorized dealer. I would want to get the Carrier 10 year parts and labor warranty. Builder's will typically use the cheapest sub-contractor. The installation needs to be done properly otherwise this expensive equipment will never function properly.

3)You should request a copy of the Manual J calculation. This is the will indicate the heating and cooling requirements for each floor. The furnaces sizes seem to be reasonable for a house of this size. I think 3 tons of cooling are fine for the first floor. I am not sure about 3 tons for the second floor. It seems it may be marginal. A load calculation will verify the requirements.

Mike, appreciate your response. To answer your questions, the house is size is correct. Based on your suggestion I asked about the additional equipment and this is what I got:

1. The coil is Carrier model CNPVP3617
2. The thermostat is Honeywell Pro 5000

The base 13 SEER equipment, if we don't chose this option, is Trane 4TTB3036 for the condensing units and Trane TUC1B080A for the furnaces. The thermostat will be the same, I don't know what coils are included in the base units.

I am still waiting for the Manual J calculation.

As an aside, we also have a Carrier humidifier LFP, no model specified, on the main system. Not sure if we need one on the second system.

I have not looked at the basement zone control at all. In our initial discussion I was told that it would require separate ducting with the price that was quite high so we decided against it. I imagine it's more than just a thermostat in the basement?

I don't see Trane or Carrier listed on the HVAC subs website and Carrier does not list them as an authorized dealer. They may be but I haven't spoken to anyone yet to check on this.

Thanks again,

human