My name is Tom. I am a union electrician local 134. I would like to set up a meeting to look at the job in order to give you an accurate estimate.I am available any time tomorrow. Please call me at 773 406-8769. Thank you.... more
Whether you should run one or two systems primarily depends on square footage and layout. One unit can reasonably do 2000-2500 sqft. You can push it to 2800, some even argue 3000. However at those square footages you tend to run into balancing and distribution problems along with challenging the system. A lot of guys, especially the cheap ones, aren't very good at solving such issues. Some home layouts by their nature are better off with 2 units. Lots of people put in one anyway o save upfront costs and regret it later.
Since you are in OP I'll assume a stucco 4 square or brick bungalow for the rest of this. Please, please, please don't get rid of the boiler. A hot water system is better than any GFA system. Realistically you won't save nearly the space you think you might be getting rid of the radiators. Unless all registers will be on ceilings you will still need floor space for registers to distribute air. The floor space saving idea is a myth.
People are often really only worried about the space radiators take up in the bath and kitchen. There are other radiator options that can solve space issues. You can also replace your existing boiler with a newer 90+ high efficiency unit. There are some very nice units out. This will also save you gas money.
As far as the AC goes, you can install AC while still having a boiler. The two basic options are an air handler with ductwork or a spacepak system. Spacepak costs a bit more but it is generally worth it. Unless you have lots of attic knee walls or a basement you don't care about its a better option than an air handler. Adding a chiller to your boiler is an option but too expensive for standard residential.
I know everybody loves GFA. It's another one of those great marketing successes. Of course, the other big issue is cost. New GFA is far cheaper than new radiant. In your situation switching over isn't going to save you anywhere near what you think. I've been doing this for 30 years and have seen a lot of people disappointed after getting rid of their boiler system.
If you do decide to go GFA ask the contractor to provide a Manual J & D load calc. Manual S for equipment sizing would be a nice bonus. He doesn't know what those are? Find another contractor who does.... more