What is Radiant Floor Heating?
Radiant floor heating is rapidly becoming a popular option in new home construction in the United States due to its cost-effective efficiency. There are three different types of radiant heating systems: hydronic, electric, and air-heated. Electric and hydronic radiant heating systems are more efficient, and consequently more popular, than air-heated systems. Heat from a radiant system does not rise like heated air from a traditional heating unit; it spreads in all directions. This characteristic makes it possible to heat a large area using a lower temperature.
Electric Radiant Heating
Electric radiant heating systems are the most versatile when it comes to installation. Rolled cables are attached in a looping pattern via braces to mats, mesh, or film constructed of resilient, heat-conductive materials. The mats can be embedded in the concrete slab during construction, installed under the subfloor, or even placed directly under the flooring, depending on type. Due to the versatility of installation options, electric systems are frequently the best choice for after-construction additions.
Electric radiant floor heating is controlled by independent zone thermostats that can be set to heat just the floor for barefoot comfort on chilly days, to raise the temperature of a single room, or to heat an entire house. No moving parts means no maintenance. This convenient method of heating is also gaining popularity as a method to de-ice driveways and sidewalks as an environmentally friendly alternative to chemicals or salt and a people-friendly alternative to backbreaking shoveling.
Hydronic Radiant Heating
Hydronic radiant heating systems circulate heated water through tubing embedded in the concrete slab. Due to the nature of the installation, it is usually done during construction. The advantage to a hydronic system is choice of power supply. The water can be heated with electric, solar, geothermal, natural gas, oil, wood-fired boilers, or any combination of these. Although most commonly hydronic systems are used for whole-house heating, they can be installed with zone control using a series of pumps.
Problems with this type of heating in the past were due to inferior tubing, sometimes requiring that the floor be ripped up for repair. Today’s materials are stronger, more leak-resistant, and should not become brittle with age, so the system is far less likely to require attention.
Air-Heated
Hot air heating is simply not very efficient in comparison with electric and hydronic. For this system, air is heated and pumped through a system of pipes embedded in the floor. Because air cannot retain a great deal of heat, this method warms the floor itself, but cannot be counted on to warm an entire house, requiring that a secondary method of heating must be employed.
Flooring Options Compatible with Radiant Heating
Before you consider types of flooring for your radiant heating system, check with a professional. If you’re installing radiant heat in a new home, flooring choice should be carefully considered, and measures should be taken by the builder to insure dry installation. After a hydronic heating system is installed, most experts agree that the heat should be turned on and run for at least 3-6 days before the flooring is installed to leach any moisture from the concrete. If the slab itself is less than 60 days old, extend the drying time to 30-60 days, especially if you are using any kind of wood or laminate flooring. Always consult the flooring manufacturer’s instructions for exact drying time instructions.
Porcelain, Ceramic, and Stone Tile
Tile and stone are ideal types of flooring to use with a radiant floor heating system. All are excellent heat conductors, do not expand and contract with heat and are highly resistant to warping or cracking, making porcelain, ceramic, or stone tiles your best choice for floor covering over radiant heating.
Carpet
Carpet is not a bad choice of floor covering for a radiant heat system, but is not a good conductor for heat. As a result, your toes may be toasty but it will be more difficult to heat the entire room. The best carpeting option for radiant heat is a thin carpet with a low pile, Berber for example, and a thick pad.
Laminates
Laminates can be used with caution. Careful consideration must be given to the installation to insure the underlying floor structure and concrete is dry in order to minimize changes dues to heat and moisture and avoid warps and cracks. Adhesives are also important to consider. Follow manufacturer recommendations for best results.
Vinyl
Vinyl flooring has come a long way since the old linoleum floors of the sixties. While it is not an ideal choice for heat conduction, some vinyl floors can be installed over radiant heat with a temperature limit set by the manufacturer. Poor quality vinyl flooring may discolor or emit a foul odor when heated.
Wood
Wood has a natural tendency to react to both temperature and moisture, so installation over radiant heating has to be very carefully engineered and will be far more successful in a dry climate.
Wood is not a static material. It swells and contracts with changes in temperature and moisture in the air, which can be problematic when it comes to floors, especially in areas of high humidity. For best result, look for a kiln-dried wood that is quarter-sawn as opposed to plain-sawn. Quarter-sawn wood has a tendency to expand in thickness and not width, so it’s less likely to warp or crack. Many experts recommend that you run the radiant heating for at least 72 hours before taking delivery of the wood flooring, then store the wood in the room where it will be installed with the radiant heating turned on to help the wood acclimatize to the moisture content in the air. The drier the concrete, the more successful the installation will be.
Hardwood
Installing hardwood over a radiant floor heating system is tricky, but can have warm and beautiful results. Always raise the heat gradually, allowing the wood to adjust. Sudden temperature changes can cause damage to the structure of the floor.
Engineered Hardwood
One wood flooring option generally more suited to use with radiant heat is engineered hardwood flooring. Engineered hardwood flooring is made up of several layers of solid wood or fiberboard, much like plywood or particle board. The multiple layer construction makes engineered flooring much more dimensionally stable and less likely to expand or contract with changes in temperature. In addition, most engineered flooring can be “floated” making it ideal for installation over concrete. The suitability of an engineered hardwood floor will depend on its construction, and the wood species and adhesives used to in its manufacture.
Always consult the manufacturer or retailer to determine whether a particular type of flooring is suitable for installation over radiant heat and whether use with radiant heat will affect the product warranty.
Bill Snyder
Looking for a contractor in the South Butler, PA area who installs Radiant Heat Flooting
Thanks
Bill
Pat C.
We are undertaking construction of a new home that will have a walkout basement and radiant heat on the first floor for the main living area. There will be a geothermal system for the radiant heat. I am considering bamboo or cork flooring. Anyone have knowledge as to the advisability of this?
carole gilchrist
Hydronic radiant tubes are rarely installed in concrete anymore, due to adverse chemical reactions between the lime of concrete, and the metals of piping or connectors. Most radiant floors these days, are a PEX system, supported by mdf or wood substrate, with aluminum channels and face plates to direct the heat upward. None of your answers to questions regarding radiant floor heat seem to reflect this. I am interested in (1) the conduction or resistance of your flooring materials- and (2) whether the materials would tend to (over time) change color along the channels, leaving a shadow effect of the heat tubes below. I’m trying to compare engineered woods and bamboo- against porcelain, ceramic, stone, and even cement tiles.
jammer
I am adding ‘staple-up’ floor radiant to the main floor on our 1928 house. Half of the floor is wonderful original narrow oak, laid on bias 1″ planks. The other half is a 40 year old addition that has traditional plywood and luan and tomorrow gets Armstrong Alterna vinyl tile, grouted joints. Armstrong says 85F max surface T on their floor, and obviously I will be very cautious on bringing up the heat under the hardwood. Here’s the query: Even if everything is controlling well at 80F surface, if a person leaves a jacket on the floor, or throws down a sleeping bag, or a pile of towels from the clothesline, that portion of the floor will now be insulated, and thus quickly exceed the 85 limit in a small area without the floor thermostat finding out about it. Likewise, even a 3 x 5 rug at the door or in front of the sink and an 8 x 10 area rug in a room. We just started up the radiant in our second floor bedroom last week, and after hours I thought it wasn’t working. then I slid my hand under the quilted shirt I left on the floor. Hot! If 80-85 is such a critical number, what happens when we leave insulating materials on just small parts of the floor? Thanx,
Wendy
We are installing radiant heating in our basement. Would plywood work as a flooring option?
Thanks
besiules grindys
To make radiant heating the best sollution is to have cast pavement. I believe that it keeps the largest amount of heat and is easy to monitore. I would never change it into smth else, because it is soooooo good, believe me :)))
Trudy
When installing engineered hardwood over in floor heating, should you use a foam underlay or install directly over the concrete.
John Moffitt
We have a radiant floor heating system installed under concrete in our basement. We are considering low pile nylon carpet or carpet tile squares with no pad. Would there be a problem gluing the carpet squares with radiant floor heat? We realize that the carpet would inhibit the efficiency of the radiant floor heat somewhat. The house is four years old and we have no moisture problems although our sump pump does run occasionally if we have an extremely wet period with heavy rains.
SUsan
QUESTION: Turning screened-in porch into 4-season art studio (adding walls). Want to put radiant floor heat over cement slab already covered with shiny oil porch paint. That will work just fine? YES? Will cover heating coils with tile. Please explain why i might need to remove paint before laying heating pad.
Many thanks for any comments.
Susan
sue
To Streets,
I know what you mean. Some of the questions are the same that I have but no answers or comments……
corinne
we are installing laminate flooring over a concrete floor. besides the foam padding I was told we need a vapor barrier which is a thin plastic. the question is, I would also like to install electric radiant heating that is in a mesh type roll. is the heat from this ok to sit on top of the plastic vapor barrier?
Streets
It seems to me that this is just a place for a comment and not a questions and answer place. So far no one has had their questions answered online, so I guess I won’t ask my question ..
Might be better off if some of the questions asked were answered on this website, I would that that would be the better thing to do…Thankx
Camilla
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georgia
I’m trying to design a flooring system where the hydronic system is visible and you can see the water running underneath the floor. is it possible to use a glass or perspex floor and still be able to heat the running water?
Mary Ann Garner
Hello, I have an old house and want to add electric radiant heating and a floating laminate floor in my kitchen. The existing floor is already 2 layers of plywood and linoleum. Will I have to rip the top layer of Linoleum up and add some kind of sub floor to install the heating mats?
Lynne
We installed Viega hydronic radiant floor panels and want to use quarter sawn oak on most of the floors with porcelain tile in the bathrooms. i want something more resiliant in the kitchen and was hoping for something like cork or marmoleum. I am concerned about cork’s inability to transfer heat. Will the room be cold because the cork doesn’t allow the heat to penetrate? If I use vinyl, I am concerned about the temperature of the floor as it affects the glue and if there could be any fumes released when the heat is on. Any experience/advice appreciated. Thanks.
Carla
What a wealth of info on your website. I am redoing my master bath with tumbled travertine tiles with a border accent that includes the same type of stone along with some glass tiles – a stone/glass mosaic. I was wondering if installing electric radiant heat mats below the glass tiles would be problematic in any way. My contract doesn’t really know & was thinking he would just stop short of the border but then I will not have the heated floors leading into my water closet which is not ideal. Any guidance will be greatly appreciated.
Linda PUls
Great questions and answers. Here is one more: We have hydronic radiant heat installed in cement under tile floors. How long can we go (number of hours or days) if the power goes out and the house gets cold before we have to worry about the pex tubing bursting due to freezing temperatures below 32 degrees.
Thank you, Linda Puls
Dalis
I have a small bathroom addition with saltillo tile floor. No heat or AC as it is a flat roof not connected to main house, although the room itself is. My question, can the radiant heat system be put over the tile instead of ripping it up since I don’t even know what is under it beside earth, and then new tile installed on top. I have a room to build the floor up as there is a small step up into the master bedroom.
Dalis
Lily Ann Plumb
My daughter and I disagree on… Can you nail engineered wood flooring over radiant heat mesh, I say no, you should use a floating floor or tile, She says you can nail through the radiant heat mesh, just don’t hit the wiring. What do you think?
Marg
Hi we have put an in floor heating system in our shop over a concrete pad. We delayed the installation of a floor covering and now find that the pad had cracks and had lifted in some parts and sunk in others. I want to put a sub floor over this to level out the area in preparating for vinyl tile installation. Everything I can see asks that we nail or screw every 24 inchs or so. I can’t really do this as I am afraid of puncturing the tubes carrying the water. Can you advise on what I should use and how to install without the nail/screq methods??
Melanie
We have built a new house and had electric heat installed in our main floor bathrooms before we tiled them. And now both bathrooms neither electric infloor heat work. And the electrician that installed it says it not his fault and neither does the carpenter that poured the mortar over the top of the heating system. They are blaming the tile layer. What do we do to get the floor warm because we are not willing to tear up the tile floor to replace when it was the Carpenter and the Electrician (whom are brothers). Please Help, we are tired of the dishonesty with these two brothers! But we would like heated floors.
Ray
Hi. I was wondering if I could fasten the electric radiant heat strips to the basement
ceiling to heat the floor above. The heat will travel through 1/2″ plywood and 1″mud than 5/16″ tile. Thanks in advance for your help.
Ardythe Lantz
We have installed luxury vinyl over a cement radiant heat floor and find it has a strong smell of vinyl! Any idea why it would smell so? Considering taking it up.
Rose Moehring
We just did a remodel job adding an additon and put radiant heat under the concrete. We just closed it up and it is getting cold outside. We noticed a crack in the floor before we had a chance to get the room hooked up to be heated. What type of flooring would be best for the floor that has a crack running down the middle of the room. The crack just came as the weather has gotten colder. It is thin but we are worried it will gap.