What is a radiant heating system?

Considering a new radiant heating system for your home? You’ve come to the right place.

In this piece, we’ll discuss the different types of modern radiant heating systems, their pros and cons, and the cost of installation.

What is radiant heating? 

A radiant heating system transfers heat directly through the walls, floors, or ceiling of a room. The warm air rises through a process called convection, delivering heat to the entire room.

Radiant heating systems have a range of benefits over central heating systems:

• Radiant heating is more energy-efficient, as leaks and holes in ductwork waste 20-30% of the air in a central heating system.
• The reduced energy waste from radiant heating may lower your utility bills.
• Radiant heating systems are discreet. They have no visible grilles, air handlers, or vents.
• Radiant heating systems operate quietly with no fan or compressor.
• Radiant heating has no impact on indoor air quality.
• Once installed, radiant heating systems are low-maintenance.
• Electric and hydronic floor heating systems pair with modern smart thermostats.

Types of radiant heating systems

Radiant heating systems rely on a range of heat sources from water heaters to solar-powered boilers. Some varieties can double as cooling systems in summer.

Air-heated radiant floors

Air-heated radiant floors use ductwork installed beneath the floor. Hot air passes through the duct. A slab of concrete, located between the ducts and flooring, conducts the heat. As the air rises, the room gradually warms.

Air-heated radiant floors are uncommon. The ductwork makes air-heated floors less cost-effective than electric and hydronic radiant floors.

Electric radiant floors

Electric radiant floors use a network of electric wires. The wires are installed beneath flooring with a wide surface area and strong heat transfer, such as ceramic tile.

Electric radiant flooring is often used as supplemental heat for bathrooms and other small rooms. Whole-home applications are uncommon, since electric heating is less cost-effective than hydronic heating.

Electric radiant flooring is a good choice for retrofit applications or existing homes. Many HVAC professionals connect the wires to plastic mats, cutting the installation time.

Hydronic radiant floors

Hydronic radiant flooring uses a network of water-filled tubes. A boiler or water heater warms the water.

Hydronic radiant floors are used for whole-home radiant heating. The temperature can be controlled separately from room to room for convenient zoned heating.

Hydronic heating is compatible with a wide variety of flooring. Options include laminate, hardwood, concrete, and even carpet.

Due to the invasive and costly installation, hydronic heating pipes are usually installed in newly built homes. Still, retrofit application is feasible and safe.

Radiant heating panels in walls

Radiant heating panels are slabs lined with electric wires or hydronic tubes. The panels are installed in the lower 4 feet of the wall.

Radiant wall panels are a great option for a retrofit in an existing home. The installation is less time-consuming and expensive than radiant floor heating.

Thick radiant heating panels can make the wall jut outward. To minimize any changes in wall depth, look for panels less than an inch thick.

Radiant heating panels in ceilings

Radiant heating panels can also be installed in ceilings. The panels use a hydronic or electric heat source.

Hydronic ceiling heaters can double as cooling systems when outdoor temperatures rise. Just supply cool water to the tubes. Warm indoor air will rise, make contact with the cool ceiling, and fall down as cool air.

Radiant heating system installation

Radiant heating systems are a significant time investment. Floor and retrofit applications can be invasive, requiring 16+ labor hours.

We recommend leaving installation to an experienced professional. Tearing down drywall and ripping up flooring are major structural changes to the home.

How is electric floor heating installed?

Many professionals attach the electric cables to a set of plastic mats. Single-room installations can be completed within hours, but the new flooring may take a few days to dry.

Your HVAC professional will follow these general steps:

• Remove the current flooring if it’s a retrofit.
• Add a thin layer of mortar to the subflooring.
• Install batts of fiberglass insulation above the mortar.
• Staple or glue down the cables or plastic mats.
• Connect the mats or cables to your home’s electrical wiring.
• Top the cables with a leveling compound and flooring (usually ceramic tile).

How is hydronic floor heating installed?

Hydronic heating requires a plumber to connect the water tubes to the heat source. The installer needs access to the ceiling underneath each radiant-heated floor. In unfinished homes, this is an easy process. If you’re retrofitting, the installer may need to tear down drywall.

The plumber and installer follow this general process:

• Sketch the layout of the tubing underneath the floor. (This is why they need access to the ceiling.)
• Drill holes in the floor joists to make room for the tubes.
• Insert the tubes and staple them to the underside of the floor.
• Add batts of insulation above the tubes.
• Connect the tubes to the water heater or boiler.
• Level the floor and install flooring above the tubes.

Usually, it takes 8-16 hours to lay down 1,000 square feet of tubing. New home installation is at the lower end of that range, and retrofits can take longer.

How are radiant heating panels installed?

Radiant heating panels are easier to install than floor heating. The professional follows these four steps:

• Tear down the drywall or sheetrock.
• Insert the panel.
• Insulate either or both sides of the wall or ceiling.
• Re-install the drywall or sheetrock.

Installation usually takes 1-3 hours per room. Panels take longer to install in ceilings than in walls.

Before nailing art or mirrors to a finished wall, confirm the location of the panels with your HVAC professional. Panels are usually installed in the lower 4 feet of the wall, but it may vary.

Cost of radiant heating

Time isn’t the only investment when installing radiant heating. High labor fees can make radiant heating systems expensive up-front. However, the energy savings may make it worthwhile.

The cost data below, courtesy of HomeAdvisor, reflects national averages.

The cost of radiant floor heating

Hydronic floor heating costs $13 per square foot, on average. Water is a strong conductor of heat, so hydronic heating has lower operating costs than electric floor heating.

The water source adds to the total cost of hydronic heating. A water heater unit costs $300-$2,000, with installation ranging $770-1,450. A standard boiler unit starts around $3,000, and installation averages $3,500-7,700.

Electric heating averages $11 per square foot. The average daily energy cost of operating 100 square feet ranges $1-5. Hydronic heating is less expensive than electricity.

Here’s a look at the average cost to install flooring on top of your heating system:

The cost of radiant heating panels

Radiant heating panels are more affordable than wires or tubes at $50-60 per square foot. Panels usually measure 2’ x 2’ or 2’ x 6’.

Most rooms need one to two wall or ceiling panels. The total cost, including labor and materials, ranges $300-1,400 per room.