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4 Keys to Using Radiant Floor Heating as a Primary Heat Source

Radiant heated floors can be the primary source of heat for a room.

As homeowners begin planning remodeling projects, one question that often comes up is whether electric in-floor heating systems can be used as an effective primary heat source for a room or a home — especially when they find out about the affordability of radiant heat.

We're happy to say that it absolutely can, in the right scenario, which is an exciting prospect, especially considering radiant heat's benefits of no blowing air (which reduces indoor allergies) and soothing whole-room comfort (no cold air pockets in your room). When you install radiant heat in your floor, the warm floor can act as a large heating surface, radiating heat into the whole room from the floor up.

"Instead of overheating the room's perimeter in the hopes that the warm air will travel throughout the space before rising, subfloor heating serves up heat from below," explains This Old House's Joe Provey in a BobVila.com article. This causes the entire room — from floor to ceiling — to become warmer with radiant heat.

However, to determine if this chain reaction will effectively heat the room as a primary heating source, you must account for variables such as 1) climate, 2) insulation, 3) position of the room(s) in the home, 4) whether cement slabs or crawl spaces are present under the room, and 5) whether the type of flooring you'd like to use in the room is compatible with the requirements of radiant heat. All of these variables collectively will determine radiant heat's potential effectiveness in the room.

1. Climate

The colder the climate, the more stringent the requirements are on having a suitable room for primary radiant heat.

The colder the climate you live in, the more air tight your room will need to be in order to use radiant heat as a primary heat source. How cold does it get during winter? The colder it gets outside, the more perfectly all the other variables will have to be achieved (tight rooms with zero heat loss and quality insulation, etc.) in order to create and maintain the level of heat needed cost effectively.

2. Insulation

The insulation quality of the room(s) will play a major role in the successful use of radiant heat as a primary heating source. Some rooms will have very poor insulation overall — and this doesn't just include the insulation behind the walls. It includes how well windows and doors are sealed, how many windows there are, the number of doors or fireplaces, etc. For instance, sunrooms often have large windows, very thin walls and a lot of heat loss. In these types of rooms, electric floor heating may not provide quite enough heating capacity to keep that room at a comfortable 70 or 75 degrees, even when insulation is installed. Consider the sum of all the areas of insulation in a room.

3. The Room(s)' Position in the Home

Is the room on the interior of the home without any exterior walls to the outdoors? This will change how much heat you need to produce and how much heat loss will occur. Also, is the room located over a cement slab or a crawl space? These typically get very cold, and will absorb most of the heat. The floor will not get very warm unless special considerations are made, including the type of insulation used. We recommend you add a layer of cork underlayment (a type of insulation) under the floor. Learn why in this video, "Using Electric Radiant Floor Systems as Primary Heat Source." It will dramatically increase the energy efficiency of your electric floor-heating system, and the floor will get a lot warmer.

4. Type of Flooring

The type of flooring affects the temperature you can set the floor heat to.

The type of flooring you wish to install in a room will impact the temperature that you can set the radiant heat to and how often you need to have it running. When setting the temperature of your floor-heating system, you should ensure compliance with the floor covering manufacturer's required maximum temperature limit, if applicable to your floor covering type. Due to some flooring manufacturers' maximum temperature limitations, some floor covering types may not serve as an optimal choice for a primary or sole heating source.

In addition to the above four considerations, you can use an online tool from WarmlyYours to help you easily determine if the room you would like to heat could successfully be heated with radiant heat — the Heat Loss Calculator.

WarmlyYours' Heat Loss Calculator will tell you if your room is suitable for primary radiant heat.The calculator will provide you with a custom report that gives you valuable data and recommendations, including the average heat loss (a BTU/hour estimate) versus the BTU available from a WarmlyYours system based on the details of the room, the operating costs of the system, and a recommendation of whether radiant heat can be a primary heat source.

Taking advantage of the room(s) in your house that are viable candidates is an exciting prospect. Do your research, use the heat loss calculator, and remember that you can also call our technical support staff and we will be happy to do the heat loss calculation and answer any questions for you at no cost! From there, if the room meets the four components discussed above, then get ready to move forward!

Do you use radiant heat as a primary heat source in any rooms in your home? Let us know on the WarmlyYours Facebook page, or tweet us at @WarmlyYours.


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I have a second house in Vermont. We turn the heat down when leaving for the mid week and turn it back up on the weekends. Will this be efficient with radiant heat?

WarmlyYours Responds...

Adjusting the temperature of your system to take advantage of the times when you’re not home is a great way to save money and maintain energy efficiency. It's just one of many strategies that programmable thermostats make possible with radiant heating. However, to answer your question about your specific application, we’ll need more detailed information about your home and heating system. Feel free to give us a call at (800) 875-5285. Our Installation Support team is available 24/7 and they’ll be able to answer any questions you might have.

thermostat set to have temp at 72 at 3 o'clock in one zone so does it start before or at 3?

WarmlyYours Responds...

Thanks for reading, Larry. That's a good question. We can really only speak about the thermostats that we sell, but our nSpire Touch (and nSpire Touch WiFi) thermostats have an adaptive function that can be enabled in the "Installer Settings". This means the thermostat, after about a week of operation, will "figure out" how long it takes to get up to the set temperature for the floor the heating system is installed in. So in your example, it might take your floor 30 minutes to get up to 72 degrees, which means the thermostat would turn the system on at 2:30 so it's 72 degrees at 3. Hope that helps.

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