Combination Heating & Cooling with Radiant system

RonPC

We are considering having hot water radiant heating installed along our baseboard throughout our southwestern adobe house. The house originally had steam heat with cast iron radiators. The boiler now needs to be replaced so we want to consider all possibilities of heating. The baseboard system could have zoned loops with separate thermostatic controls.

With some internet searches, we have discovered the option of heating and cooling using a combined system. The house does not currently have airconditioning. Prior to this, we considered central air conditioning with ducts being installed through the attic. Has anyone had any experience with combined gas heating and chilling: cost, efficiency, maintainance, effectiveness, installation, etc.

We like the idea the system could be installed outside rather than our basement to avoid carbon monoxide, the need for special venting, access convenience, and the availability of additional space.

Mike T., Swampeast MO

Can you give an internet reference to the system you mention?

Most baseboard systems aren't considered "radiant" as they deliver extremely little heat in the way of radiation. "True" radiant systems are generally a floor, ceiling, wall or other VERY large, flat surface kept at a temperature MUCH lower than any baseboard system.

Some internet companies espouse running your cold domestic water through a radiant system to get "free" A/C, plus combining the radiant heat with the domestic hot water. Granted I believe in using energy wisely and creating simple systems, but the potential for TRUE HARM is rife using this scheme. If you at all value the health of you and yours do not install such a system!

Combining heat and A/C in a hydronic system has many complications. The most difficult thing to overcome is "what to do with the condensation?" Some (carefully controlled/engineered) radiant systems in some climates do produce reasonable amounts of very comfortable A/C without condensation.

Baseboards, iron radiators, panel radiators, etc. aren't really suitable to providing A/C. Not only must the condensation from such be collected and drained, but their relatively small surface area and small possible temperature differential (remember water freezes at 32°) require that FORCED convection (i.e. a fan) be used to "force" enough heat into the device.

Give SERIOUS thought before trashing your iron radiators. They are not "obsolete" because of function--they are rare in new construction because of their extremely high price.

Also give SERIOUS thought before abandoning the steam. If not done properly, steam-to-water conversion is a comfort nightmare. While current steam boilers are not as efficient as well-used condensing boilers, they are likely much more efficient than your existing boiler. TRVs are available for both one-pipe and two-pipe steam systems.