Electric Radiant Heat

Electric Radiant Heat

Electric Radiant Heat and Floor Coverings

Scott B Gwilliam, P.E.

If the decision of what type radiant heating system to use was left to the floor-coverings, it would choose electric radiant. Eliminating the risk of water/glycol leaks, standard floor-heights, simple retro-fits, almost unlimited choice of carpet padding, uniform heat flux, easier installations and superior floor or space temperature control are only a few of the advantages of electric radiant heat. This isnt to say that there arent disadvantages of electric radiant, but then Im a sparky not a plumber, so Im here to espouse the benefits and desirable features of electric radiant heat and its loving relationship with any and all floor-coverings. Oh, wait a minute, how could I forget, electric systems typically cost a fraction what hot-water (hydronic) systems do.

From the simplest of painted concrete to floors to floors that started with linoleum, added carpet, then converted to imported marble, electric radiant is truly and simply superior to hydronic radiant and here are the reasons why.

There is no water or glycol and spilled electrons dont damage floor-coverings, in fact, theres no need to even sweep them up. Seriously, the safety standards and National Electrical Code keep electrical systems safe. Yes, a cable, mesh or mat can be damaged by an errant nail or screw, but the worst case scenario is the system doesnt work as compared to a penetrated tube of a hydronic system with 100 gallons of water and glycol pumped out on the top level floor of a three floor custom home.

Built-up floor height for most electric systems is less than and some as little 1/16 thick. Most hydronic systems pour 1 to 2 of light-weight concrete over the tubes increasing construction costs and limiting the types of floor-coverings that can be installed, or expensive specially designed sub floors or sub floor overlayments, such as Wardboard must be used. If you want traditional hard-wood floors, a complex system of sleepers must be installed to allow for nailing of the wood to the sub-floor with a hydronic system as well.

Retro-fitting carpet over what used to be tile cant be easily done with hot-water systems. Changing the R-value (insulating characteristic) of the floor-covering changes the amount of heat that makes it into the space in hydronic systems, since they are designed to transfer heat via a temperature difference between the water in the tube and the floor covering surface, whereas electric systems put out a constant wattage regardless of the floor-covering insulating characteristics. Floor covering types can be changed time after time with electric radiant without changing the heating system.

Hot and Cold Spots or what some-people call spot-heating can be easily accomplished by installing higher or lower heat-density and adding a simple floor-sensor to control the temperature. Have you ever noticed how dogs or cats search for the warmest piece of flooring in a home and sleep there? We added a special tile floor heated 10 warmer for our house pet that became new sleeping accommodations for the kitty.

Uniform Heat Flux The harder the floor covering the more noticeable warm or cold spots become and the layout of the hot-water tubing and the changing temperature of the water through the loop result in changing floor-temperatures. This doesnt happen with electric heat, each foot of cable, or length of mesh or mat generate exactly the same amount of heat as the next foot making it very easy to maintain a constant temperature across the floor. If the floor-coverings are going to be different in one room or one zone, split it into two zones of electric so the desired temperature can be maintained on each surface. This is easier to do and less costly for electric than hydronic.

Electric Radiant Heat

Installation of any product is a concern and any time the cross-trade issues of installation can be minimized everyone wins, particularly the home owner. Electric systems dont require any mechanical room space or consume any expensive floor space, provided they are installed before the floor-covering is installed. Coordination with the other trades is minimal. If you want to climatize some exotic hardwood flooring from Brazil during the construction process within the space, its unlikely that youll have gas to operate your boiler, but its very possible that you can run your electric radiant heat off of temporary power to assist in stabilizing your wood before installation. Take that example one step further and you realize that all the other trades on site will appreciate the warm temperature inside if your project is located in someplace like Leadville, Colorado in February.

Independent of HVAC Electric radiant can be the primary heating system, but can also operate very efficiently if you want to warm a bathroom floor to 80 in June and your husband has the air-conditioner running throughout the rest of the house. Try doing this with your 1,000,000 Btu boiler and youll regret it when the time comes to pay your gas or oil bill.

Precise Temperature Control Adding multiple zones to an electric system costs only pennies per foot compared to dollars per foot for hot-water. Having as many zones as you ever anticipate different areas with different floor-coverings is possible and practical, with the other benefit of precise control of temperature of every space in the home.

My mother and father used to sit and watch TV (football, basketball, etc.) in a love seat in their master bedroom and my dad was always cold while my mom was always hot. I installed a two-zone electric system right underneath the love-seat split right down the middle with a thermostat for my mom and one for my dad. Believe it or not, it worked beautifully. My dads feet sat on a floor that was 85 while my moms were on a floor that was 75.

Cost Installation costs of electric radiant is almost always less than any hot-water installation and the smaller the area to heat the bigger the difference. And heres the kicker, if you save a lot of money on your radiant heating system you can spend every penny of that savings on Imported Italian Marble in your Entry and Master Bath.


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