By Allison E. Beatty
Special to the Tribune
October 19, 2007
Radiant heat is added under the floor, typically with a hydronic system that works with a warm water source, such as a boiler or a solar or geo-thermal system. Radiant heat also can be supplied with electricity
Q. Why should a homeowner add radiant heat?
A. The reason floor heat works so well is that it's an even heat. It's conductive heat and the comfort level is unbelievable. Also, it's not drafty and it's not dusty.
If you're building a new house, adding floor heating is easy. It also can be done in remodeling, but the only challenge is when you have a finished ceiling. There, it may be difficult to work above it.
Q. Where is radiant heating typically added?
A. In the kitchen, bathroom, family room, mud room and garage.
Q. Under what floor coverings would you typically place radiant heat?
A. Slate, tile and marble are commonly used. They are great because of the heat transference.
You can also put it under carpet. The challenge is that you have to find the right pad. A rubber pad is better than a sponge pad. A waffle sponge pad will trap the heat.
Q. When should you use hydronic (water-based) heat versus electric?
A. If it's new construction, it depends on what you choose for the air conditioning and heating.
If you are incorporating a boiler for heat, use the hydronic system. If you are using a furnace for heat and just want to heat a few areas, use electric.
The cost of power also is important. Gas is typically less expensive than electricity.
Q. How much does radiant heat cost?
A. In a brand new home, hydronic and electric heat are comparable in cost to install. While costs will vary by your local marketplace, it is about $15 to $20 per square foot to install either one.
Q. Are there other advantages to radiant heat?
A. Hydronic heat is easier to zone because you can move it to three or four different zones more easily than with furnace duct work.
Q. What is a heat loss analysis and why is it important?
A. A heat loss analysis is the calculation of how much heating and cooling a house needs. It's important because it helps you determine the right size system.
If you put in too big a system it never reaches its efficiency and is a waste of money. If you undersize the system it won't heat adequately.
Q. What's different about radiant heating today versus in 1991 when you first started working with it?
A. There are more installers out there and it's more competitive. At the same time, the products have come down in price. Technology also has improved.
We have some nice electronic controls where we can measure the outdoor temperature and compare it to what is going on inside and adjust the system to match the load.
Q. Are there common misperceptions about radiant heating?
A. One big misperception is that people think they should walk into a room with radiant heat and feel it coming up from the floor. Actually, it's better if they walk in and don't feel anything. The limit for floor heat is 85 degrees, which is your average skin temperature.
Q. What if you can only afford radiant heat in a few places?
A. Everybody could have some floor heating -- there shouldn't be this all or nothing approach.
We've done a lot of houses where we'll skip the bedrooms. Or, if you have a living room you don't really use, it might not make sense to add it there.
Q. How can homeowners check out a radiant heating installer to make sure they are getting a quality installation?
A. One of the biggest challenges we have is contractors who are not properly trained. There is an abundance of training out there from manufacturers.
You want to ask the installer, "Have you been to training? Have you done a heating loss analysis?"
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