The most typically asked questions about Radiant Floor Heating
and the answers that go with them...

 How does it work?   What makes it so comfortable?   Where does the warm water come from?
How Do I control room temperature?   How Efficent is it?   What about energy savings?
How do I find a qualified installer?

 Radiant Floor Heating:  How does it work?

"What exactly is radiant energy?" Hold your hand over a hot cup of coffee and feel the heat. The logical conclusion is that heat rises. Logical maybe, but incorrect! "Hot air" rises but "heat" can travel in any direction. That is why you can feel the heat of the cup when you place your hand to the side of it. Radiant energy transfer is caused by a warm surface giving up its heat to a cooler surface. Whenever there is a temperature difference between two surfaces, both surfaces will attempt to equalize.

Radiant energy travels through space without heating the space itself. It only turns into heat when it contacts a cooler surface.  Our human comfort relies just as much on radiant heat transfer as it does on air temperature, yet the majority of heating and air-conditioning professionals think only in terms of air temperature. As a result, Americans are missing out on the ultimate comfort available from radiant floor heating in their own homes or places of business.  By controlling both the air temperature and the radiant transfer, radiant floor heating can deliver comfort that is unsurpassed.

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               What makes radiant floor heating so comfortable?

The basic principle of radiant heating is to control the heat loss from the body as opposed to the heat loss of the building.  Skin surface temperature, about 85 degrees, is generally warmer than the surrounding surfaces. This makes our body a radiant panel. Walk down the frozen food aisle at your local supermarket and you will feel the heat leaving your body. The air temperature is actually the same as in the rest of the store, however, the freezers are robbing your body of its own radiant heat!

If the rate at which we radiate heat is correct, we feel comfortable. When the temperature difference between our body and the surrounding cool surfaces becomes too great, we have to put on a sweater to slow down the rate at which we are radiating.  A heated floor slows down the rate at which your body loses heat.  Its surface temperature is usually less than our body temperature, although the overall sensation is one of comfort.  Any of these radiant experiences are far more pleasant than being buffeted by the hot-then-cool breezes which are often associated with a forced air furnace.

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Where does the warm water come from?

That largely depends on the scope of the project.  For additions and small retrofits, you may be able to use anything from a water heater to tying into an existing hydronic heating system (hot water baseboard or radiator).  For large commercial structures or complete houses, I strongly recommend Viessmann heating equipment.  Viessmann has a comprehensive selection of gas and oil boilers, domestic hot water tanks, control systems and even solar heating capabilities.  This is the line of heating equipment CLIMATEC uses almost exclusively for radiant floor heating.  The entire line has been designed for low temperature hydronics, and is the highest quality and efficient equipment currently available anywhere!

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     How do I control room temperature with a radiant floor heating system?

A simple wall thermostat is generally all that is required.  An "outdoor reset control" will help the system adjust the floor temperature based on the outdoor temperature for increased comfort and economy. A big advantage is the option of a thermostat in every room.  This provides additional comfort as well as energy savings because you can turn down those rooms that are not in use or that you prefer to have cooler.

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                 What makes radiant floor heating so efficient?

"Thermal Mass" refers to the ability of a material to retain heat. For instance, a heated stone will remain warm much longer than a block of wood.  This storage of heat can carry a building through a time when energy is not available. With radiant floor heat, the floor (or slab) may be in the form of a gypsum or other cementitious material or metal plates in the panel construction.   The 'floor' responds rapidly to the change of air temperature when a door is opened. All the heat that has been "trickled" into the slab over time is released quickly to combat the cold air rolling in over the floor.  Once the door closes,  the building returns to its normal comfort setting almost immediately. The key to any radiant floor heating system is to provide an even surface temperature.  When properly designed, these systems are a good alternative for retrofitting an existing building.  Radiant floor heating systems are very stable  and maintain a uniform climate because the floor surface remains at a constant temperature.

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                               What about Energy Savings?

Increasing your comfort and, at the same time, saving money on your utility bill is a winning combination. On average, radiant floor heating is 30% more efficient than forced-hot air (or "scorched air") heating.  Multiple zoning allows unused rooms to be turned down.  Another energy saving feature is lower thermostat settings. With radiant floor heating, you feel comfortable at room air temperatures which are 3 to 5 degrees lower. You no longer have to force yourself to turn down the thermostat to save, you will do it automatically to be comfortable.

Forced-air (scorched air) systems locate registers along outside walls, under windows and in front of sliding glass doors to compensate for all those cold surfaces.  The scorched air goes up cold outside walls, across the ceiling and down to the cold air return. In other words, every place where heat loss occurs!  This is a great setup for wasting energy. Radiant floor heating directs the heat to the interior of the space and reduces or eliminates the excessive temperatures on outside walls and ceilings. This can result in energy savings of 10% to 30% in most residences and up to 60% or more in commercial spaces.

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                              How do I find a qualified installer?

The hardest part about using radiant heat in your next project may be finding a qualified installer. If you are fortunate enough to live within Climatec's service area, please call us today!  If not, contact the Wirsbo Company and have them send you their literature and names of installers in your area.  Also, check out the Radiant Panel Association Membership List.

Avoid those who appear to be flying by the seat of their pants.  The industry has been around long enough that "design as you go" is not acceptable.  The installer should have a room-by-room heat loss analysis of your building, as well as a step-by-step system sizing process.

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Climatec Advanced Heating Technologies - P.O. Box 3910, Easton PA 18043

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