Electric wire under floor heating systems

Radiant underfloor heating in homes is a very efficient and comfortable method for heating a home. There are different options for underfloor heating systems to consider, whether you are building a new home with a slab-on-grade or standard basement, adding radiant floor heat to a second floor, or doing energy-efficient upgrades to cold humid basements. See the different types of underfloor heating systems here.

But here we will cover the easiest radiant floor systems for home renovations, electric wire radiant floors. There are 3 ways to go about this. One thing we really like about this is that it steers you towards heating homes with electricity, which is a whole lot better than heating homes with "natural" fossil gas.

Types of electric underfloor heating

1. Loose cable electric radiant floor systems:

Loose cable systems involve laying individual electric heating wires across the subfloor in a serpentine or customized pattern. The cables are secured with clips, fasteners, or a mesh underlayment to ensure consistent spacing and heat distribution. This method is highly flexible, allowing the installer to tailor the heating layout to irregularly shaped rooms or areas requiring concentrated heat, such as near windows or entryways.

Flooring options over electric cable radiant heated floors:
Loose cable systems typically require a thin screed or self-leveling compound poured over the cables to protect them and create a flat surface. Once the screed layer is cured, various flooring materials can be installed, including:

• Ceramic or porcelain tile: this is an excellent option for heat conductivity and durability.
• Engineered wood: Wood floors are a great option, be sure to choose a product that is rated for radiant heat and installed using floating methods. Solid wood floors with radiant heat are far more susceptible to cupping and cracking.
• Vinyl or Marmoleum: These as well must be approved for use with radiant heating to avoid warping or damage. We recommend Marmoleum floors for indoor air quality and sustainability reasons, see here the downsides of vinyl flooring and other building products.
• Cork tiles: a lesser known but excellent eco friendly flooring option is cork, which is a very sustainable and renewable resource. 
• Polished concrete: A screed floor as a finished surface is durable, non-toxic and affordable. See non-toxic silicate sealers for concrete floors here. 

2. Electric heating mats for underfloor heating

Heating mats consist of electric wires pre-attached to a mesh or fabric backing, allowing quick and uniform installation. The mats are rolled out directly onto the subfloor and are ideal for standard room shapes. This method simplifies the process and is especially popular in bathrooms, kitchens, and other areas where spot heating is desirable as there is no major infrastructure needed like with air-heated radiant floors or hydronic radiant floor heating systems.

Flooring options:
Electric heating mats are usually installed under a thin layer of tile adhesive or leveling compound to ensure a smooth surface. Suitable flooring options include:

• Tile (ceramic or porcelain): The most common choice due to its excellent thermal conductivity.
• Stone flooring (marble, slate, etc.): Ideal for heat transfer and durability.
• Engineered wood or laminate: Approved types can be installed on top, provided proper precautions are taken to avoid overheating.
• Vinyl or Marmoleum: These as well must be approved for use with radiant heating to avoid warping or damage. We recommend Marmoleum floors for indoor air quality and sustainability reasons, see here the downsides of vinyl flooring and other building products.
• Cork tiles: a lesser known but excellent eco friendly flooring option is cork, which is a very sustainable and renewable resource. 
• Polished concrete: A screed floor as a finished surface is durable, non-toxic and affordable. See non-toxic silicate sealers for concrete floors here. 

3. Insulated underlay systems

Insulated underlay radiant heating combines electric heating cables with an insulating layer, optimizing heat retention by minimizing heat loss to the subfloor. This method is highly efficient and often used in renovations where additional insulation is required. These systems are compatible with various flooring types and are particularly energy-efficient for long-term use.

Flooring options:
Insulated underlay systems allow for multiple flooring types to be installed directly over the insulated layer or a thin screed layer:

• Carpet: carpets and area rugs will create an insulated layer between your feet and the floor, so thinner is better to ensure efficient heat transfer.
• Vinyl or Marmoleum: These can be compatible if designed for radiant heating.
• Poured concrete or screed: This is a great option for underfloor heating in basement renovations and can be used as a finished floor.
• Engineered wood: This works well, provided it is radiant heat-compatible like all the other options.

When selecting flooring, always confirm compatibility with radiant heating systems. Materials like solid hardwood or thick carpets are less suitable due to potential heat resistance or damage. Proper installation and floor preparation ensure the best performance and longevity of the heating system.

Some other questions people ask about underfloor heating –

Which is the best electric floor heating system?

We don’t have a specific brand to promote, our best council for choosing the best electric underfloor heating would be to pick a reliable brand with a good warranty, in la ength of time but also one that is simple to understand without a lot of conditions. Make some calls, read some reviews, and like anything -  if a company wants your business, they should stand behind their products and answer your questions upfront. 

From our experience, there's always a cheaper product available, but there are also good products at a fair price. However, just like with electric blankets, you don’t want one that develops hotspots that burn out. Someone I know installed a full bathroom floor with electric under-tile heating, only to discover, after everything was stuck down and wired up, that the tiler had accidentally gouged the cable with his notched trowel, causing it to short directly to the floor. This not only created a hassle but also caused a weird tingling in the feet just before the lights went out!

The moral of the story: always check the resistance of your heating wires to ensure they meet specifications before covering them with expensive ceramic tiles. Even the best electric underfloor heating can have issues due to mishandling.

Are electric floor heating systems under tiles in bathrooms smart?

They sure are. Electric underfloor heating can be added to bathrooms either during the initial build, or while doing bathroom renovations. Warm bathroom floors are a great thing to have when stepping out of the shower, and they also help evaporate moisture. it warms your feet at the source, but that heat is also in the building envelope so its a win/win, super happy feet, and no added heat loss!

Is electric in floor heating efficient?

Yes it very much is. Any radiant heated floor is efficient in the way that it heats your physical contact point with your house, namely your feet. Warm feet will often allow you to tolerate lower room temperatures in a house because it conducts heat directly into your feet rather than your feet conducting heat into the floor, which is highly uncomfortable! Read more here about designing a home for thermal comfort.

Is electric under floor heating expensive to run?

No more so than any other electric heating system in your home such as an electric furnace, electric radiators or convection heaters.  Electric resistance heating costs virtually the same to operate whether it is a furnace, a toaster, a hair dryer, or your swanky heated bathroom floor and heating with electricity is clean and environmentally responsible.

Can you put electric floor heating in concrete?

Yes, and slab on grade under floor heating needs to be done at the initial build stage, obviously. Typically you would see hydronic heating in concrete floors, or air heated concrete floors even, but if you price it out and electric wire heating is your preference in the end then go for it.

Make sure any radiant under floor heating system you install has the capacity to deliver the necessary BTUs for the particular house design and climate. You can ensure that by having a heat load calculation done, and you can find the best local HVAC professionals in the Ecohome pros directory.

Also make sure you have sufficient insulation below your slab to be sure those BTU’s are ending up in your house and not the ground below. See here to learn more about how much insulation a basement floor needs so aren’t out of pocket by creating a heavenly warm environment for the worms in the ground below your house.