Anyone here have experience with purchasing a central air system for their house? If so, I need some advice about getting quotes, etc.

I have a two story house (in North Carolina), each floor has it’s own A/C system, the main floor has ducting underneath the floor and the second floor has ducting over the ceiling, the upstairs connects with an “air-handler”; the compressor and heat exchanger is on the ground outside. The main floor has a “gas pack” natural gas fired furnace for heating in winter, gas is cheaper than electricity.

Each floor should have its own A/C system and thermostat, bathrooms at night could be cooler than the main floor and during the day the bedrooms could be warmer because no one is there. Larger is not always better for A/C because you want “cleaner air” for health, the larger unit will cool and shut off sooner and less air is cleaned by filters. You can have too much A/C tonnage!

You look up a/c contractors in the phone book or online. When they come to your house they will tell you how many tons you need and how many compressors you’ll need. I cannot imagine anyone saying you just need one. Our house is one story and we have two !

Thanks, all who have responded so far. Mom only has money for one unit which is concerning given the above responses.

You can go with a lesser unit by planning usage. Rarely used areas can have their vents blocked when not in use. If you get a system with “zones” you can alternate cooled areas as needed.
Just enter your various Qs not the google bar, you will get a lot of useful responses.
Getting info and quotes from places like Home Depot and Lowes (if you don’t have any idea who in the area does this work) is helpful, and they are pretty competitive in pricing.

Good luck, this is a pain in the neck. I just did it last year. The local company that had many referrals was impossible to deal with and too pricey. A small specialty group was much easier to deal with, charged less for the same units, and was much quicker. And brought treats for my dogs. :-)

The answer to the 2 or 3 ton question depends upon the size of the house and where it’s located. Up here, a cold climate, we get by with 1 ton! (12,000 BTU/hour) Our heating season is typically 6600 heating degree days. Our cooling season is typically 600 cooling degree days.
The contractor in your area will know those numbers for your area and can make a good recommendation. In general I prefer to undersize rather than oversize.

To add to @LuckyGuy ‘s comments:

1) will they use existing ducts or will they have to do something about running new ducts around the house?

2) How well insulated is the place? Will cool air stay in?

3) Are you thinking of AC only, or more of a heat pump?

4) are the windows single pane or double pane? (again, insulation from the elements)

Sizing is everything!!

@LuckyGuy and @elbanditoroso…the house is fairly large (1900 square feet), and we are in Baltimore. Our summers can get pretty muggy. The guy we are probably going to go with is recommending no bigger than 2.5 ton, and says a two ton unit should be fine.

No duct work is needed, as the house was always set up for central air. My parents bought the model home which is why it was never put in there. Insulation is decent,m but not great. No heat pump, Windows are single pane.

We had a house that size twenty years ago and only had one unit . Very hot , muggy summers. What complicates matters is that the house, which sounds narrow, has three stories and the heat will go up the staircases.