Everything You Need to Know
About Radiant Floor Heating

By: Toni Matthews-El Energy efficiency

Radiant heating systems provide heat through panels or walls. When specifically supplied through the floor beneath you, it’s called radiant floor heating or floor heating.

Even though the name conjures up images of walking on heated floors, much of the effect involves heat rising from beneath you to warm the air around you. Imagine sitting in front of a fireplace on a chilly evening and feeling the heat from the flames drift toward you. Radiant floor heating keeps you warm in a similar fashion.

Benefits of radiant floor heating

Here are a few distinct advantages of underfloor heating:

  • It’s typically more efficient than other heating systems. For example, forced-air heating can cost homeowners hundreds of dollars each year due to heat leaking from ducts.
  • Radiant systems are basically silent, allowing you to enjoy the heat without being disturbed by constant noise.
  • Hydronic, or liquid-based, floor systems don’t use much electricity which can help you cut back on energy spending.
  • As long as your floor coverings are thin enough, you can use a variety of coverings and materials (think: tile, stone, carpet, wood, laminate, and vinyl) on your floors that won’t interfere with the system’s functionality.
  • It’s great for people with allergies because the system doesn’t distribute allergens like forced-air systems do.
  • It improves air quality and keeps the air fresh and oxygen-rich.
  • It’s safe for homes with young children and pets—the heating system is safely tucked away and doesn’t have sharp edges or hot surfaces like radiators do.
  • The liquid in hydronic systems can get heated in many ways, letting you find a method that’s most efficient and affordable for your home.

Drawbacks of radiant floor heating

While the benefits are plenty, there are a few disadvantages to choosing radiant floor heating for your home:

  • Radiant floor heating has a long warm-up period, which means you won’t feel its heat immediately after turning the system on. 
  • Installing slabs and insulation boards for radiant floor heating could lead to an increase in floor height up to a couple of inches.
  • Installation can take up to a week depending on the system you install.
  • Though radiant floor heating is cost-effective in the long run, installation costs can run a bit high.
  • Radiant floor heating is only for heating. If you want to cool your home during hot summer months, you’ll need to install a separate system for that need.

Types of radiant floor heating

Radiant floor heating involves three different types of systems:

1. Air-heated radiant floors

These systems use air tubes to provide heat. Because air is less effective at holding heat than other mediums, air-heated radiant floors aren’t as cost-effective for in-home use. This type of radiant heating is more common in larger commercial buildings.

2. Electric radiant floors

These systems feature the use of electric cables or mats with electrically conductive plastics. The cost-effectiveness of an electric radiant floor will depend on the floor’s thermal mass. If large enough, you’ll only need limited electrical input to keep the floor heated for eight to ten hours.

A thick concrete slab works best for this type of medium; it will help you save money by cutting down the amount of electricity needed. Because electricity prices can be high in some locations, you’ll want to pay attention to factors that can potentially reduce (or increase) costs.

3. Hydronic radiant floors

This is a liquid-based heating system that’s considered the most cost-effective and efficient method of floor heating. With this system, a water heater or boiler heats up cool water that is then pumped through a pattern of tubing that’s laid out beneath the floor. Some types of hydronic radiant floors are designed to control the flow of hot water, making it possible to regulate the room temperature.

How to install radiant floor heating

If you’re someone who is very hands-on, it’s possible to get your radiant floor heating installed over the course of a weekend. It ultimately comes down to your installation method and work rate. If you don’t feel confident in your home improvement skills or want to ensure your system is installed properly, consider hiring a professional to help.

When preparing to put in your radiant floor system, there are two popular installation methods to consider:

1. “Wet” installation⁠

Wet installation is the oldest modern method of installing a radiant floor system. For this type of installation, cables or tubes are embedded into a solid material. It’s possible for the tubing or cables to get embedded in a thick concrete foundation slab or a thin layer of gypsum or concrete.

You can usually get away with pouring thick concrete onto solid earth. However, when pouring concrete on finished flooring that isn’t solid, you may need additional floor support due to the added weight. 

2. “Dry” installation

Dry installation is a newer method for setting up radiant floor systems. The method involves installing cables and tubes in an air space beneath the floor. Sometimes the tubing and cables are suspended under the subfloor, between the joists.

It’s possible to place reflective installation under the tubes to direct the flow of heat upward. There are multiple approaches, but the overall appreciation for dry installation stems from the fact that it’s quicker than the traditional “wet” installation and costs less.

Tips for designing radiant floor heating in your home

As you go through the installation process, keep these tips in mind when designing radiant floor heating for your home.

  • Consult a professional if you’re not sure if your new floor can support the concrete that you intend to pour onto it.
  • If you find that some rooms in your home have floor coverings while others don’t, consider using a separate tubing system to allow these rooms to get heated more efficiently. These rooms will need more heat flowing under them to compensate for the insulation provided by floor covering.
  • Choose floor coverings that will heat the space more efficiently. Ceramic tile is the most preferred choice, as it adds thermal storage and easily conducts heat. Other popular choices include linoleum and vinyl.
  • Opt for laminated wood flooring over solid wood to cut down the possibility of it cracking or shrinking from the heat.
  • If you want to include carpeting in your home, choose a thin carpet with dense padding. Install as little carpeting as possible to avoid ineffective heating.

Is radiant heating worth it?

Before moving forward with radiant heating, there are some crucial factors to consider.

Installation cost

Radiant floor heating typically varies depending on the type of heating you choose for the size of the room. Laying out an electric system in a 50-square-foot bathroom can cost as little as $265 while a 120-foot master bathroom installation can run between $600 and $800.

Additionally, don’t forget to factor in the cost of a new floor, including materials like adhesives and sealants. On average, tiles for your floor will cost around $2 per square foot.

Efficiency

If you want to be efficient, hydronic floor heating is likely your best option. Though electric radiant floors are efficient, they’re a more expensive option. Air-heated floors are the least efficient medium for heating a residence. Think about which system is most efficient and cost-effective for your heating needs.

Energy-related expenses

If using electricity is costly where you live, you’ll likely shy away from electric radiant heating. Hydronic radiant heating can be cost-efficient and is more energy-efficient than other heating systems. You could also consider combining radiant heating with solar power for additional energy and cost savings over the long term.

Frequently asked questions

How does radiant floor heating work?

Mediums like air, electricity, or a liquid (usually water), are fed into a floor through a pattern of cables or tubing and used to heat flooring. As time passes, the floor slowly begins to warm up. Some heat escapes into the air, slowly causing the air circulating within a room to get warmer (a process similar to convection).

How much does it cost to install radiant floor heating?

On average, radiant floor heating will cost $10– $12 per square foot. The overall cost will depend on the type of floor heating, as well as the size of the room or number of rooms that need to be heated.

What is PEX tubing?

This is a cross-linked polyethylene pipe that’s used in both “in-floor” (embedded in a thermal mass) and “underfloor” (installed underneath the plywood) system. It’s typically associated with hydronic radiant systems. Pipe sizes for radiant heating are usually 3/8-, 1/2-, 5/8-, and 3/4-inch-thick in size.

Can the floor get too hot with radiant floor heating?

The floor temperature is only a problem if, for example, the temperature of the water entering the system is too hot. If radiant heat gets trapped, it might not be able to properly dissipate into the air. In situations like this, a repair is likely needed.

Does a radiant floor heating system make a lot of noise?

Radiant floor heating is relatively quietly, allowing you to enjoy a warm room without disruptive noise.

Can a radiant floor heating system help those with allergies?

Radiant heating is a popular choice for those with allergies as it doesn’t spread dust and allergens in the air like forced-air heating systems.


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