Radiant heating is a term often used to describe a method of residential or commercial heating that is an alternative to traditional forced-air heating systems, which use ducts to circulate air throughout a home. In a radiant heating system, heat is transferred directly to objects and people in a room, creating a comfortable and efficient way to keep your home warm during the winter months.
Radiant heat differs from convection heating (which relies on heated air to transfer heat to the other objects in a room) because radiant heating is much more efficient. With radiant heating, the heat is transferred via infrared waves directly to the solid objects in a room which results in very little lost energy. Heated air doesn't stay heated for very long and it's very inefficient at transferring thermal energy to solid objects.
With the use of radiant heat as a primary heating source, temperature levels can be maintained more easily - and at a lower temperature - than with any other form of heating. That means, for every degree you lower your thermostat, you can save 5% off your current heating bill. That's 25-30% in annual savings. You can use our Cost Calculator to get an accurate operating cost within your home.
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How Does Radiant Heating Work?
Heat comes in three main categories: conduction, convection, and radiant.
Conduction heating is when a heat source is in direct contact with another object that is being heated. As an example, consider an electric stovetop with one of the "burners" on so that it is glowing red. If you slide a pan onto this burner, the heated surface of the stovetop makes direct contact with the bottom of the pan, which acts as a conductor to heat whatever is in the pan. This is an efficient method of heat transfer but isn't practical for home heating.
Convection heating relies on a heated medium (like air) for heat transfer. In residential or commercial heating, this usuaully takes the form of a central heat source which heats up air and then circulates it around a building to heat up not only the rest of the air but also the solid objects in the building. Because the heated air's mass is much less than that of the solid objects, this form of heating involves a high degree of heat loss. These systems also often suffer from heat loss in the form of "leaks" in the ductwork that can be hard to identify and fix.
Radiant heating systems work by installing electric mats or hydronic tubing beneath the floor. The heating system turns essentially the entire floor into a heat source which then radiates from the floor in infrared waves which pass from the heat source to the objects being heated to create a warm and comfortable environment.
A really good example of radiant heat in your everyday life is the sun. When you're sitting outside and it's cloudy, it can feel chilly (because the clouds are blocking out some of the radiant energy from the sun) but as soon as the clouds part, the heat returns. That's radiant heat and the good news is that you probably don't have clouds in your house between your floor and yourself to block the heat!
Unlike traditional forced-air systems, radiant heating systems do not rely on ducts or air to distribute heat, which means they do not lose energy through leaks or inefficient transfer.
Radiant Heating vs Forced Air Heating
Radiant heating offers several benefits over traditional forced-air systems, including:
Energy Efficiency: Radiant heating systems are more energy-efficient than forced-air systems because they do not lose energy through leaks or inefficient distribution.
Comfort: Radiant heating provides a more comfortable and even heat distribution than forced-air systems, which can create hot and cold spots throughout a room.
Noise Reduction: Radiant heating systems are quieter than forced-air systems because they do not rely on noisy blowers or fans.
Design Flexibility: Radiant heating systems can be installed beneath any type of flooring, including tile, carpet, luxury vinyl tile, and hardwood.
Health Benefits: Radiant heating systems do not circulate air, which can reduce the spread of allergens and other airborne particles.
Here's a useful article where you can learn more about the comparison between radiant heating and forced air heating.
Types of Radiant Heating Systems
There are two types of radiant floor heating systems. Modern radiant underfloor heating systems use either electrical resistance elements ("electric systems") or fluid (typically a mixture of water and a chemical antifreeze element) flowing in pipes ("hydronic systems") to heat the floor. Either type can be installed as the primary heating system or as localized floor heating for thermal comfort. Electrical resistance can only be used for heating; when space cooling is also required, hydronic systems should be used.
Electric systems are easier and less expensive to install than hydronic systems, but they can be more expensive to operate. Electric floor heating also comes with the added advantage because the coverage can be broken up into zones. So for example, you can heat only the rooms you use during your morning routine instead of wastefully running the system for the entire house. Hydronic systems are more expensive to install, but they are generally more energy-efficient and cost-effective in the long run, however, this benefit comes with an important caveaet: the amount of time the system is actually on. Hydronic systems take longer to "ramp up" to comfort heating levels than electric ones do so if you are using the system on a programmed schedule, it may actually be less energy efficient. Click here to learn more about the differences between hydronic and electric floor heating systems.
Other applications for radiant heating in and around the home can range from snow melting systems to keep outdoor surfaces like driveways or walkways clear of ice and snow to high-end luxury items like towel warmers. Additionally, radiant panel heaters, which are typically wall-mounted devices that put out infrared heat, can be installed in rooms were replacing the floor and installing an electric floor heating system isn't feasible.
Electric Floor Heating Systems
Just like there are many forms of radiant heating, there are many types of electric floor heating systems. The most popular versions are cables, rolls, and mats. All three of these utilize heated cables but each has unique pros and cons.
Floor heating cables can be installed with either fixing strips or with an installation membrane, both of which help to hold the cable in place (with proper spacing between the heating elements) prior to it being embedded beneath the floor covering. Fixing strips are the more economical option but are also more labor intensive while membranes, particularly uncoupling membranes, help cut down on installation time and offer crack isolation in addition to the uncoupling benefits.
Radiant heating rolls consist of a floor heating cable secured to a mesh backing. Rolls are typically the most popular version of electric floor heating and for good reason. They're easy and fast to install and provide excellent, reliable performance for the heating system. Because the heating elements are secured to the mesh, when they're installed a user can simply cut the mesh (never the cable) when they're at the end of a run. This method is called "cut-and-turn" and it's among the most reliable and speedy ways of installing electric floor heating. They're great for providing full coverage radiant heating in traditionally shaped (square or rectangular) rooms.
Floor heating mats are similar in construction to the rolls but are meant to only heat a certain area in a room. This method of heating is called "spot heating" and is used to heat the parts of your floor with the most foot traffic. This helps cut down on both material costs during the installation and operating cost for running the system moving forward.
It is important to make sure that your heating system matches your floor covering to ensure optimal performance and compliance with national and local electrical codes.
Electric Floor Heating for Tile, Stone, Marble, Hardwood & Luxury Vinyl Floors
Find the ideal solution to warm tile, stone or luxury vinyl tile floors with electric floor heating.
Experience the combination of beauty and luxury with heated tile floors.
Our TempZone electric floor heating systems are available in several configurations including cable, roll, and heated floor mat.
Explore this floor heating application
How to Install Radiant Heating
But how are these radiant heating systems installed? We offer both embedded and floating heating systems so the installation methods for those will be different.
For embedded systems, the floor heating element will need to be secured to the subfloor and then encased in either thinset or self-leveling compound (make sure to consult your installation manual to determine the right material for your heating system or better yet, you could consult a Radiant Expert from WarmlyYours). Then, typically, the floor covering can be installed on top of this. Embedded radiant heating systems are the most common and some of the most popular floor coverings for this type of heating system are tile, natural stone, luxury vinyl tile/plank, and even nailed hardwood.
Here's a great video overview of our TempZone Flex Rolls being installed under a luxury vinyl tile floor.
Floating heating systems are installed with floating floor coverings so you won't need to use an embedding adhesive (which can cut down on total project costs). Some of the most common floating floor coverings are laminate, engineered wood, and carpet (U.S. only). Here's a good overview vide of the installation for radiant heating under a floating floor.
History of Radiant Heating
The warmth of the sun and the heat from an open fire are radiant heat rays, so in an elementary sense, Radiant Heat is as old as the sun and fire.
It is difficult to say when man first began to utilize radiant heating for his personal comfort. Anthropologists tell us that early man chose south-facing caves because the rock would warm from the sun during the day and radiate that heat into the cave at night.
Its application, as far as authentic records are concerned, dates back to early B. C. centuries. Excavations uncovered the remains of many radiant systems constructed and used by the early Romans.
The famous baths of Caracalla, various baths at Pompeii, and some of the Roman Emperor's barges provide outstanding examples of engineering skill displaying in the design of these early “warm air” Radiant Heating Systems. These heating systems were called hypocausts and they used fires and pipes beneath the home to circulate heated air that warmed up the floor and the solid objects in the room.
The next step was to introduce a hot water boiler with a system of large pipes through which the hot water was carried. The pipes were either exposed or placed under or behind grilles to give off heat in the various rooms. The earliest recorded date of this method seems to be in 1790 when Sir John Stone installed a heating system of pipes in the Bank of England. Gradually the importance of aesthetic consideratons became manifest, and radiators were subsequently introduced to take the place of pipes in the rooms. Steam was utilized and took its place with hot water as a medium for heating.
It was not until 1908 that radiant heating was introduced on a commercial basis. It was then discovered by Prof. Arthur H. Barker that small hot water pipes embedded in plaster or concrete gave good results and formed a very efficient heating system. Prof. Barker developed the first design for what is now known as "panel" radiant heating and devloped a floor method of heating used in the Liverpool Cathedral - fittingly enough, the warm air floor method used in the Cathedral was designated the "Romana" method of heating.
Since then, many new advancements, such as the creation of electric floor heating, have helped to popularize radiant heating, by making it easier to install and more reliable in operation. Nowadays radiant heating systems can be found in homes across the world and in many commercial and public buildings as well!