Types of Radiant Heating Systems

With an understanding of how radiant heating works, we are going to take a look at the various options that are available when it comes to a hydronic heating system for the home. Heating designs for a radiant system can be tailored to most residential needs, whether it is a new custom home, or a remodel in a historic area. The flexibility of this type of advanced home heating system, as well as the high levels of energy efficiency, have made radiant heat an increasingly popular choice for contractors and families alike.

Basic Equipment

Every residential hydronic heating design will require the following basic elements to heat the home:

Boiler – The means to heat the liquid.
Liquid Medium – Traditionally, this has been water, but some systems allow for other liquids or water and antifreeze mixes.
Manifold/Thermostat – Connected to the thermostat, the plumbing manifold is the hub for directing water flow and room temperatures.
Tubing – PEX or some other form of plastic tubing is pretty much universal with all hydronic systems, with very little in the way of copper or other rigid piping used.
Heat Exchanger – The radiator, baseboard heater, or in floor element that transfers the heat into the home.
Pump – To keep the heated liquid in circulation, so that the warmth is constantly replenished.

With this understood, there are many different options within each element that are used depending on the type of hydronic radiant system you want for your home.

Boiler Options

The cornerstone of any hydronic system is an energy efficient boiler that heats the liquid with little to no heat loss or wasted energy. In addition to the standard boiler for radiant heating systems, there are a few different boiler options, as well as components that work in tandem with your boiler.

Tankless Hydronic Water Heaters – Much smaller than the traditional tankless water heater, these heaters are specifically designed to allow on demand, energy efficient hot water for radiant heat.
Combined Hot Water and Heating Systems Boiler – Originally more common in commercial building applications, combined boilers that allow for hydronic heating and home hot water usage are starting to appear for residential use. These can be designed for water tanks and tankless water heating alike.
Solar Water Heater – A solar heater will not provide enough heated water by itself, but it can increase the energy efficiency of the system and work in tandem with your boiler. A panel on the roof heats a liquid that runs through tubes inside a water storage tank. This creates water that is naturally pre-heated and requires less energy from the boiler to bring to the right temperature.
Geothermal Heat Pump – Similar to the solar heater above, geothermal heat pumps can preheat the water by using the natural warmth found several feet below the soil. This reduces the amount of natural gas, electricity, or oil that your boiler will need to heat the water.

Liquid Options

Traditionally, hydronic heat consists of hot water as the method of transferring heat, and while this is still the norm, modern radiant systems can also incorporate other liquids to heat the home. Glycol is a common antifreeze that is added to a closed loop system. This can help to protect the water from freezing if the piping runs through an exposed area, as well as increase the waters boiling point. The need for antifreeze or other liquids other than water will be explained by your installer and designed around your specific heating needs.

Heating Exchangers and Their Locations

Underfloor Radiant Loops – Radiant flooring has become very popular for new home construction, as it is much easier to add into the concrete or floor joist system during the original building of the home. It can provide consistent comfortable heating evenly throughout the home.
Baseboard Heaters/Radiators – Hydronic baseboard units and radiators can be much easier to install for home remodels because they require less tubing below the floor. They can be inconspicuously located along the walls of a room, but you should make sure they are not blocked by furniture, so that the heat can radiate out into the room.
Walls and Ceilings – Similar to installing a radiant floor as above, wall and ceiling radiant panels are available to be placed behind walls, and can heat a broad area. These panels are most often run with electric radiant heat, as opposed to hydronic, due to water damage possibilities. They can be great additions to residential hydronic heat, especially in spaces where large areas of floor are covered by cabinetry, such as kitchens.

Outdoor Radiant Heating

In addition to meeting your indoor heating needs, outdoor radiant heating systems can be a very helpful addition to your overall HVAC design.

Snow Melt – For those who live in areas with a good amount of snow fall or ice, a radiant heating system for melting snow on the sidewalks and driveway can make you home much safer. Additionally, radiant roof heating can help protect your roof from ice dams and future leaks due to snow and ice buildup.
Heated Pools – Anyone who likes the feel of a comfortably heated pool will appreciate radiant heating loops beneath the pool walls that allow for an energy efficient way to keep the pool warm and extend the swimming season.

Electric Radiant Heating

Hydronic systems are not the only means of radiant heat. Electric heated floors are an alternative method of radiant heating that can be suitable in some residential heating designs. While this website’s focus is about using a whole house hydronic system, it is important to know all of your options so that you can make a decision on which configuration or combination of systems will work best for you. Here are a few things you should know about an electrically heated floor:

Design – Electric radiant floors work in a similar fashion to an electric blanket. Typical installation is done by rolling out a thin layer of matting or mesh that contains the low voltage electric heating coils laid out in a pattern similar to hydronic radiant tubes. They are glued or stapled to the subfloor and a thin layer of self leveling cement is spread over the top. After this sets up most flooring types can be placed above the electric flooring with tile being the most popular choice. Finally, the system needs to be connected to the home’s electrical supply and a thermostat. You will want to make sure that the electrical connection is done by a licensed electrician, but the actual floor installation is a great project for a do-it-yourself homeowner.
When to Use – Floors that are heated electrically are not usually used as a whole house heating system, instead electric radiant flooring is used as a secondary system to focus on specific areas of the home. Their easy installation flexibility allows homeowners with forced air heating to complete a small remodeling project and add the luxury of radiant heat to the areas where they most need it. Bathrooms, kitchens, basements, and garages are popular areas to install electric heated floors because they allow you to have evenly heated warm floors at the specific times you and your family enjoy that space.
Cost – An electric radiant floor system can have a less expensive initial installation cost when compared to hydronic heat. This is due to the ease of laying down the electric coil matting instead of hydronic loops, and the fact the electric heated floors can be readily connected to the home’s electrical system. On the other hand, operation costs for electrical radiant heat is much higher than that of a hydronic system, which is why most people prefer their whole house heating solution to be hydronic, and save the installation of electric radiant floors for targeted areas only.

Radiant hydronic systems can be designed around these many different options as mentioned above. This will make sure that the final heating plan will meet your family’s needs of comfort and long-term affordability.

Whether you are trying to add a super energy efficient radiant flooring system to a new custom home, or maximizing the space you have in a home remodel with tankless hydronic hot water units and radiators, there is a hydronic heating plan that can work for you