Question

Has anybody installed radiant heating for the kitchen or bathroom floor?

Really hard to find information about cost savings and how radiant heating can impact your house bill. Is it worth it? Can it also cool your home? How much does it cost and where can I find the product?

Answer

Polly Osborne, FAIA, LEED AP

Answered by Polly Osborne, FAIA, LEED AP

Los Angeles, CA

Polly Osborne Architects

January 26, 2010

Radiant floors are usually less expensive to operate than conventional forced air because heat isn't lost through the ducts. The heat is transferred directly from the floor to you.

The reason it is hard to find direct information on how efficient radiant heating actually is is because it can vary, depending on which type of system you have and other environmental and materials factors, such as the ventilation in the room and what materials the floors are made of. 

Hydronic vs Electric

The most efficient systems on the market are hydronic systems. They carry heated water from a boiler through pipes in the floor. There are some very efficient boilers on the market these days and the system can also be tied into solar hot water systems.

Hydronic systems must be designed by an expert and that expert can tell you how much money you are saving by using it.

  • Monterey Energy Group and their subsidiary National Radiant Design Center is one of the oldest groups in the country designing radiant heating.
  • I have used them many times and find their fees very reasonable. 

If you have solar photovoltaic panels you could consider electric radiant heating. These systems take quite a lot of energy so you would want to use them only in small areas, such as a bathroom. 

Radiant cooling

I have never used floor pipes for chilled water. If you have good ventilation and control air flow to allow for convection, cooling can be very effective without any sort of chilled water system.  

In humid areas cooling doesn’t work well.  If the floor is chilled it can lower the temperature to the dew point and cause condensation on the floor. In other drier areas, night cooling can be used to pre-cool the floor, preventing the floor from over heating. This technique is also used in areas that overheat from direct sunlight falling on the floor.  It isn’t normally enough to do the entire house.

Air to water heat pumps

Air to water heat pumps are new to the market in the US and change everything. Now we can use a solar grid-tied PV system to heat the water.

Because grid based PV systems have come down from $12/watt to $5/watt and about $2.50/watt after incentives for a new house (California-based estimates), these systems, like the Daiken Altherma, are very viable.

They are incredibly efficient and Monterey Energy Group has achieved net zero results using them on about 100 projects.

Read more at netzeroenergycertified.com.

Flooring materials

Concrete and tile are the best floor materials for radiant heating, because they don’t insulate the space between you and the heat, and because they are excellent solar mass. 

 

For more information:

Read more expert Q&A about radiant heat here on GreenHomeGuide.

The U.S. Dept. of Energy has published an overview of radiant heat here.

Tagged In: radiant heat

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