steam heat radiators and adding central air (floor, heaters, ceiling)

[pms033]

What happens if you don't have an attic and want to add central air to house with steam radiator heat? Can you still add central air?

[MidValleyDad]

You just put a valve in the steam line and run it through a refrigerator box to run chilled water through the lines and chill the radiators down. It helps if you put a fan in the room to blow more air across the chilled radiators. If you are in a very humid climate you may need drip pans under the radiators as they cause the humid air to condense (We never had to remember to fill the dogs water bowl in the summer)

[TrapperL]

Assuming you have a basement- yes. I have boiler heat and central A/C in one of my rentals in Michigan. Works great. The A/C comes from floor vents with the ductwork in the ceiling of the basement. The unit sits pretty much in the middle of the basement with a return air duct along side of the unit. Considering the union wages up there, the install was cheaper than I expected. The house is 1200 sq ft plus basement.

[mkarch]

Most of the new houses here with radiant heat have ductless ac.

[joe moving]

I would install ductless mini split units.

Depending on where you live and the size and layout of your house, I would install HEAT AND COOL mini split units like Fujitsu RLS3 or RLS3H (3H is for -15F or something) so you can use them for heat as well. You may find them to be more efficient than the steam heat.

Advantages are going to be cost and efficiency and zoning.
If 1 dies, you still have another unit running to keep you sane
Heat - may actually be cheaper than your steam heaters

Disadvantage - they are ugly and you don't get a "duct" in every room so if you close lots of doors often, you may have too large temperature differences.

Wall Mounted 9 - 12,000 BTU - Fujitsu Ductless Mini-Splits

Cost to install about $3000 per unit - Again, depending on the size of the house, 2-3 units is probably plenty.