Definitive Guide to Radiant Floor Heating Systems

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Radiant Heat Flooring

Imagine stepping from a warm bed or shower on a cold day onto a warm floor. That’s what will happen if you have radiant floor heating installed in your home. 

Radiant floor heating systems warm the objects and people in the room directly by infrared radiation. This method of heating is much more efficient and comfortable than systems that heat the air; with the heat coming from the ground up, the room’s temperature will feel much more consistent with no cold spots or drafts.

History of Radiant Floor Heating

Many people assume that radiant floor heating is a fairly new concept, but it’s actually one of the oldest ways to heat a home. Radiant floor heating systems go as far back as 5000 BC in China and Korea.

radiant floor heating
Image Credit: Wikipedia.org

Around the third century B.C. the Romans began perfecting this system by creating layers of tile, concrete,, and an additional layer of tile that was raised on pillars that allow the heated air to circulate more freely.

This system disappeared with Rome, however, and wasn’t revived until around the 17th century in Europe, when Sir John Stone first began using heated water circulated through pipes to heat first greenhouses and then commercial spaces.

This led to a refinement of the method, as well as some of the first research into how radiant heat transfer worked.

Radiant heating first came to the US during the Civil War when heated air similar to the Chinese concept was used to help warm hospital tents. In 1907, it was discovered that small hot water pipes could be embedded in concrete or plaster, and the process began to be put into use.

It wasn’t until Frank Lloyd Wright began to see the benefits of the system, however, that it became more widespread in use.

Concept Behind Radiant Floor Heating

radiant floor heating
Image Credit: Sustainability Workshop

The concept behind the system is that the heat is radiating off of the surface, similar to how you can feel the heat from a burner on the stove from several inches to feet away. So, while the system isn’t warming the air directly, it makes you and the objects in the room feel warmer. 

Benefits of Radiant Floor Heating

radiant floor heating
Image Credit: Watts.com

Radiant floor heating systems have a lot of benefits for the homeowner. Because you aren’t heating the air, the temperature in the room will feel more consistent from floor to ceiling, since the heat isn’t leaving cold areas on the ground.

You’ll feel more comfortable in a room with radiant floor heating, and in many instances, it doesn’t use as much energy so your heating bills can be a lot lower. It works under a variety of flooring types, so it won’t detract from the beauty of your home.

And because it’s not blowing air through ducts, fewer allergens are being circulated through your home. It’s also easy to run, completely silent, and fairly easy to install. 

Key Components to Radiant Floor Heating Systems

hydronic heating
Image Credit: ThisOldHouse

Depending on the type of system you choose, there are only a few key components that you need to make the system operational.

For hydronic systems, all that’s necessary is a hot water heater or boiler, the in-floor pipes, which are usually made of PEX tubing, and the plumbing manifold including any necessary valves and fittings, which runs the hot water from the boiler to the floor.

For electric systems, you’ll need a heated floor mat, which is wired to your home’s electric panel, and in all systems, you’ll need a thermostat to control the system and the heat. 

Radiant In Floor Heating Installation Types

There are two basic styles of installing radiant floor heating – wet and dry installations.

Both systems can use either hydronic or electric power to heat the floor, the installation names come from how the tubing or electric wires are installed.

hydronic heating
Wet Installation Diagram
Image Credit: PennState College of Earth and Mineral Sciences

In a wet system, the tubing or wires are embedded in the concrete or another material that can easily transmit heat.

It’s called a wet system because the wires or tubes are placed into a wet material; once the material cures the floor will be dry, even if you use a hydronic heating method.

radiant floor heating
Dry Installation Diagram
Image Credit: PennState College of Earth and Mineral Sciences

In a dry system, the tubing or the cables are placed in a cavity below the floor or between floors.

They aren’t embedded in anything. Both methods will give you efficient, consistent heat, but you may find that depending on where you are installing the heating, that one method works better for you than another. 

Common Myths about Radiant Floor Heating

in floor heating
Image Credit: ConcreteNetwork.com

While radiant heating has been around for thousands of years, many people still believe it to be a new technology, which in turn has led to several myths and misconceptions surrounding it.

The first being, just how old it is, with most people believing that it’s only been around for the last 20 years or so.

Another common myth is that it only heats the floor, not your home. This is only true if you’re using a small, electric-only system for supplemental heating; most radiant heating systems will warm your entire home evenly.

A third myth involves the fact that heat rises; many people think this means the system won’t work.

But in actuality, it’s hot air that rises, so in a system with forced hot air, you will have varying temperatures around the room as the air warms, rises, cools, and falls again. Radiant floor heated rooms stay consistently warm throughout.

Many people also believe that the systems take a long time to work and that they aren’t very precise.

Most systems can be used to warm up quickly, however, and with precision laying of the tubing or cables, you can get the heat exactly where you want and need it. 

Radiant Floor Heating vs Other Radiant Heating Sources

The floor isn’t the only area you can install a radiant heat system. They can also be placed on walls and ceilings as well.

Radiant underfloor heating is probably the most efficient method since there is an even distribution of heat within your living space.

in floor heating
Image Credit: BTL Property

Radiant panels can be installed on walls to heat small rooms. They tend to be less effective than floors or ceilings because it’s difficult to cover large spaces.

Radiant ceilings, however, can often be even more efficient than radiant floors, and because it’s only hot air that rises, not heat itself, a radiant ceiling can create a very comfortable room, without needing to disturb your current flooring.

Types of Radiant Floor Heating Systems

There are three different types of radiant floor heating systems to consider. Each has its own attributes that may make it a better or worse fit for your home. 

1. Air Heated Radiant Underfloor Heating System

Air heated systems are the oldest type of radiant heat, the type first used in China, Korea, and Rome. Air heating systems are a little less efficient than the other types and are therefore less common. Rather than pumping air directly beneath your floor, the heated air is circulated through a series of tubes, similar to how water is used.

The difference is that the air is lighter, and easier to push through the tubes, so it can be a faster system. 

heated floors
Image credit: EcoHome.net

With this system, you’ll use a heater, but instead of pushing the air through ducts to vents, it will push the air through ducts or tubes in your floor, heating it. 

It could be a challenge for this system to be energy-efficient. However, because the heaters are embedded in the floor along with the ducts, they take up less space in general; you don’t need a large furnace or boiler.

You do need to make sure that the system is closed and well sealed, and it does need to be installed with a wet installation. The heaters are housed in boxes within the concrete and can be placed anywhere for easy access. This can make maintenance and repairs easier if required. 

Air heated floors can be used in all types of buildings and with all floors, including hardwood, engineered hardwood, tile, stone, laminate, vinyl, linoleum, and concrete.

They can be installed either in a structural slab on grade or in a suspended floor system. 

In a slab install, the ground is leveled then covered with a layer of polystyrene installation. This is then used to hold the furnace boxes, piping, and ductwork, which are held in place with a level of mesh.

Concrete is then poured over the installation in the normal manner of creating a slab. Curing begins after 3 days, and the entire process takes roughly 3 weeks. 

Retrofitting is possible, but still requires the use of a poured concrete, wet installation. Dry installations may not be possible with this type of system. 

Costs of Air Heated Underfloor Heating System

heated floors
Image Credit: Ecohome.net

The cost to install an air heated system is roughly $14 a square foot, which is similar to hydronic systems. This does not include the cost of the flooring installed over the ducts or the cost of the concrete slab. 

Many people choose to use a partial solar panel system as well to help offset the costs of operation, as they may be higher with this type of system; the installation costs do not include the installation of solar paneling. 

The cost of using this type of system has a lot of variables, including how well insulated the house is, how big the system is, and whether you combine this with solar paneling.

In most cases, you will see savings of at least 10% or more on your energy bills. 

Common Issues with Air Heated Underfloor Heating System

The most common issue with this type of system is the ductwork. Most ducts end up corroding over time inside the concrete, which leads to issues down the road.

Only one company is currently producing a non-corrosive form of ducts that can be used in this type of system without continuous problems. The concrete must be completely cured before the system can be activated to ensure success. 

This system cannot be installed dry, which can be problematic for second-story installations and non-slab installations.

Air can’t hold as much heat as water, so they tend not to be as efficient in general and are mostly reserved for commercial spaces. 

Application of Air Heated Underfloor Heating System for Commercial and Industrial Spaces

radiant heating
Image Credit: EcoHome.net

Radiant heat is very efficient in general, but problems with leaks in older hydronic systems led to the discontinuation of this type of system in schools, industrial buildings, and commercial office buildings.

Air heated radiant floor systems offer an alternative to the old hydronic systems.

This type of system is most commonly installed in commercial spaces, rather than residential homes, and is perfect for convenience stores, office buildings, schools, and industrial buildings of all kinds. 

2. Electronic Radiant Floor Heating System

electric radiant floor heating
Image Credit: TheSpruce.com

In an electronic radiant floor heating system, wires or cables, and occasionally mats in small spaces, are installed in either a wet or dry installation beneath the flooring. The wires are directly connected to the home’s electricity and the floor is controlled by a thermostat. The system is made up of a few components, including in floor sensors, a heating element – either a mat or wires – and the thermostat.

For small spaces, mats embedded with the wires can be laid in a thin layer of mortar, with the mats cut to fit the area. In larger spaces, the wires themselves are usually looped about 3-inches apart throughout the space, also embedded in a thin layer of mortar.

The system uses a type of heat-conducting plastic to help transfer the heat from the cables to the floor above. 

Electric radiant floor heating systems are often a little faster to use, as the cables begin to generate warmth immediately, rather than needing to have air or water heated first, then pumped through the system.

They can be installed under any type of flooring without issue, and the cables are thin so they don’t end up raising the floor the way that a thicker system would.

Electric radiant heat systems are more expensive, however, both to install and to run. They can be less invasive and faster to install, especially in small spaces like bathrooms, they can often be used as a form of supplemental heat. 

Costs of Electric Radiant Heating Systems

There are several types of electric floor heating systems, so your exact costs can vary depending on which you choose. However, you can expect to pay around $20 a square foot for the system and installation.

You will still save 10% to 20% on the average cost of electricity for forced hot air furnaces, simply because the system is so efficient at heating the room; no heat or energy is lost in the process. 

Types and Installation of Electric Radiant Floor Heating Systems

While the various systems mostly operate the same way, they can come in a few different types. These can include mesh mats, solid mats, and loose wires, as well as infrared heating. Infrared heating uses a system of carbon fiber strips attached to silver bus bars connected to copper electrical strips.

The entire system is packed between two layers of thin plastic sheeting. This type of system is the most efficient of the four. 

Application of Electric Radiant Floor Heating Systems in Commercial and Industrial Applications

Electric radiant floor heating is frequently used in commercial and industrial applications. The different types of mats or loose wires allow for customization that can cover both big and small areas.

The versatility of the installation – allowing for both wet and dry installations, as well as retrofits of all kinds, means that it can be installed very quickly and put to use almost immediately making it a good choice for large buildings that may have individual offices to heat and control. 

3. Hydronic Radiant Floor Heating System

hydronic heating system
Image Credit: PlumberMag.com

Hydronic radiant floor heating uses hot water to warm your home, and is the most efficient of the three systems. It consists of a boiler or hot water heater, which warms the water. The water is fed through a series of PEX tubes that are embedded beneath your floor in either a wet or dry installation.

The hot water circulating through the tubes is what warms the floor above. The system is completely closed, allowing the water to run in a loop or in an open system. 

This type of system can be installed beneath any type of flooring and is very efficient as well. It uses less energy than a traditional forced hot furnace, saving you up to 30% on your energy bills. It has different types of installations available, so it can be retrofit or put in a new installation. 

Types of Hydronic Floor Heating Systems

hydronic heating
Image Credit: HydronicHeatingDaikobi

There are essentially two different methods using a hydronic radiant floor heating system – an open-loop or a closed-loop process. In an open-loop process, the water is pulled from a source such as well, heated, and pumped once through the system before being discarded.

In a closed system, a heat exchanger constantly heats the water, which runs in a loop through the floor. In this type of system, the water is contained so there’s less chance of things being contaminated or introducing things like bacteria into the system. 

Key Components of a Hydronic Radiant Floor Heating System

A hydronic system is fairly simple, consisting of a heat source, tubing, plumbing manifold, and liquid medium, heat exchanger, and pump.

For your heat source, you can use nearly any method of heating water including water heaters, boilers, geothermal heaters, solar hot water heaters, or tankless systems. The tubing is almost always PEX, a flexible tubing that does not crack, corrode, or break over time. 

For your liquid medium, most people choose water, but in a closed system it is possible to use glycol, or a mixture of water with antifreeze if your system is at risk of freezing in cold temperatures when not in use.

A heat exchanger is needed in closed-loop systems and a pump is needed to help keep the water circulating through the tubes. The entire system is connected to a thermostat for control. 

Here’s a quick video from ProHome on the various parts of Radiant Hydronic Floor Heating System.

Proper Use of Radiant Hydronic Heating System

This system can be used as the sole source of heating in your home. It will require regular maintenance of the boiler to help it continue working properly, and you may find that the system is efficient enough that you don’t need to set your thermostat as high as with other sources of heating. 

Installation Process of Radiant Hydronic Heating System

radiant floor heating
Image Credit: Nu-Heat

The installation process is fairly easy and can be done either wet or dry. The boiler is hooked up to the plumbing manifold, a series of pipes and valves that direct the water to the floor. The manifold is connected to a series of tubes, which can be run in a loop across the floor, roughly 3-inches apart. In a wet installation, this can be covered with concrete or in a dry installation, it can be run in the cavity between floors. 

It can be installed beneath any type of flooring including wood, tile and stone, laminate, vinyl, linoleum, or concrete, and the entire process depends mostly on the size of the installation as well as whether this is a wet or dry installation; wet installations will need approximately 3 weeks to cure, while dry installations can have the top flooring put down immediately and can be operational within a few days. 

Hydronic Radiant Floor Cost

The cost to install a hydronic system is among the lowest of the three types. Starting costs are around $10 a square foot for dry installations and can go as high as $14 a foot for wet installations. This does not include the cost of the finished flooring or the concrete in the case of a wet installation.

Running the system is more efficient than other forms of heating and can save you as much as 30% on your heating bills, depending on the type of heat source you choose, and the type of fuel it uses. 

Common Problems and Fixes in Hydronic Radiant Heat Flooring Systems

radiant floor heating
Image Credit: Griffith Energy Services

There are few problems with most hydronic systems, and the most common are associated with the valves and the circulator pumps. They do need to be repaired or replaced on occasion.

Another common issue is airlock, which is what happens when air gets introduced into the system and prevents the water from circulating. Allowing the air to escape at specific valves can help fix this issue. 

Repairs usually cost between $200 to $500, depending on the issue and whether or not parts need to be replaced. 

Application of Hydronic Heating Systems in Commercial and Industrial Applications

Like the other forms of radiant in floor heating, hydronic heating systems are frequently used in commercial and industrial applications. They can help create more even heat throughout the building at a lower cost, so they make sense for larger companies and businesses that own their own facilities, rather than renting out space.

These types of systems can often make it more comfortable for employees, as well as for customers in retail settings, without hot or cold spots to deal with. 

DIY Radiant Floor Heating

While most DIY systems using radiant heating are electric, it is possible to install some small sections of hydronic heating if you are comfortable working with the plumbing.

Some companies will send you a kit, which contains all the various pieces and a layout you can use to install the system. 

In general, DIY should only be done for supplemental systems as well as for dry installations; wet installations and whole-house systems should be left to the professionals.

Radiant Heat Flooring Companies that Offer Products and Installation Services

Here are some of the companies that provide radiant heat flooring installation and top of the line products.

  • Radiantec – they manufacture and sell hydronic heating materials for your floor. They have been in business since 1979 and is based in Lyndonville, Vermont.
  • NuHeat – they provide electric radiant heat systems through several dealers in the United States. Their system is relatively easy to install in different flooring materials whether it be laminate or engineered wood.
  • Orbit Radiant Heating – another great provider of electric radiant underfloor heating system. They offer heating systems from Tech Series and Nexans. You can head on to their website and order your products. You can also request a quote from their website through a customer service representative.
  • WarmlyYours – WarmlyYours is one of the most reputable companies when it comes to floor heated systems. They provide all-around services when it comes to residential and commercial heated floors.
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