If you are looking to lower the cost of heating the house, reduce an environmental impact, increase comfort, and have better control of the heating system, then hydronic floor heating is what you need.
NO more unpleasant appearance of radiators, baseboards, or louvered floor vents (registers).
Hydronic floor heating systems are designed to heat your home efficiently. The system is using heat from the heated fluid that is running through the pipes which are installed under the floor. The system delivers heat directly to the floor and then radiates to surrounding objects. This is why it is called radiant floor heating.
A traditional heating system, such as the forced-air type, heats the air directly (by blowing the warm air through the ducts and into the room), which then warms up the people in that room.
Radiant floor heating works by directly warming the people, utilizing the floor as one massive radiator.
In hydronic floor heating systems, boilers, furnaces, and water heaters are used as the heating source to heat water (usually). The circulation pump moves the heated water through the set of pipes installed under the floor. In order to increase the heating surface, the tubing is laid out in a serpentine pattern.
The heat is then delivered to the floor which acts as one gigantic radiator, from where it radiates heat to the room air, people and surrounding objects. Space is heated from bottom up.
Water then circulates back to the heating unit but with a lower temperature. It gets reheated and sent out again, making the whole system a “closed-loop system”.
Apart from closed-loop systems, there is also an open system that uses domestic water heater to provide heat for floor heating and potable water. Water first passes through the floor and ends up in your shower or kitchen sink. In closed-loop systems, there is no connection between the floor system and the domestic water supply.
In order to provide better control, heating systems are split into heating zones. Each zone starts from the “control center” which is actually a plumbing manifold system. This is where the pump delivers heated water from the heating unit.
The temperature of the water is set and controlled by the thermostat, so each zone has its own steady temperature. The temperature should not exceed 85 F, as the higher temperature can damage the flooring or put additional stress on system elements.
Hydronic heating systems can be installed indoor for home heating and outdoor for pool heating or melting snow on driveways and sidewalks.
The main components of hydronic floor heating systems used in residential applications are grouped into three categories:
The heat source for hydronic heating is usually a boiler, water heater, solar water heater, heat pump, or any other (if applicable). The heating unit can use the following fuel sources: natural gas, propane, oil, electricity, wood, or solar.
Heating fluid – water is a common heat transfer medium, but if it is needed, glycol can be added as antifreeze to protect the system from freezing.
Manifold and thermostat – used as the control center to control the temperature in each zone separately.
Tubing (usually PEX).
Heat exchanger (radiators, baseboards, or set of pipes).
Circulation pump - it moves the water (and heat) from the heat source through piping and back.
Two methods are used when installing the hydronic floor heating:
Wet installation. This method involves the installation of the plastic tubing into the concrete. Two applications are used: slab on grade and thin slab over the frame floor.
In a case of the slab on grade system, radiant tubing (PEX is the most popular) is secured to the rebar, reinforcing elements or wire mesh before concrete is poured. This method is used in new constructions.
The thin slab method is used in both new homes and retrofits. The piping is attached to the subfloor while the thin layer of self-leveling concrete is poured over the top, raising the floor height approximately 1.5 inches.
Dry installation. Dry systems use grooved panels to loop the tubing. The panels with tubes are then covered with flooring. This system requires proper insulation placement and heat reflectors underneath to direct heat in the right direction.
Also, the pipes can be suspended under the floor surface.
Recap: Hydronic floor heating systems can be installed in concrete floor slabs, in-floor joist, and below wood floors, carpets, or vinyl floors.
Either method you choose, keep in mind to design it correctly and per instructions. Correct pipe spacing, water temperature, flow rate, and type of flooring are crucial because you want the heat output to meet the heat loss demand of your home.
PEX or cross-linked polyethylene is a durable and flexible tubing that is leak-resistant, non-toxic, does not corrode and become brittle over time, is resistant to high temperatures, and is flexible. It is the most used type in today’s homes, and currently, it is considered as the industry standard.
If the heated area is large, it will likely be broken up into several areas called “zones”. Each zone is controlled by a single thermostat and circulation pump and can have one or many circuits, but as long as the length doesn’t exceed the maximum recommended. It is also recommended to keep zoning to the minimum because you will have better control, and there will be no waste of energy, time, and money.
Whoever designs your hydronic system, he should have info about your lifestyle, the size of the heated floor, and home construction in general.
Except the hydronic radiant heat, there is also an electric type. While they function the same way - heating the home from floors to the ceiling, they are also different.
Electric radiant heating utilizes a low voltage electric heating coils that are woven into the plastic mesh and arranged in a similar fashion as the radiant hydronic pipes – serpentine layout.
However, the coils are much thinner, there is no fluid running through, no heating device, and they are glued or stapled to the subfloor with the thin layer of cement on top. Due to its simplicity, installation is an easy DIY project, where the electric coils are connected to the electrical system of your home. A thermostat is also used to set and control the temperature.
As opposed to the hydronic system, electric radiant systems are used only for small areas, as an addition to an existing heating system, and to heat areas such as bathrooms, kitchens, garages, and basements or where the floor is usually cold.
As mentioned, they are easy to install and usually do not require professional installation. Also, there is no maintenance involved.
As the system utilizes electricity, operating costs are higher, while the initial cost of the product and its installation are lower.
As with other types of home heating systems, hydronic is also subjected to problems.
Those problems could arise due to poor home design and construction, low quality of workmanship, and quality of materials.
Mistakes such as lack of insulation under the concrete slab, bad flooring selection are some of the issues related to bad design/construction.
The most common problems that are found in installed floor heating systems are:
Leaks – the most common reasons for fluid leaks are pinched tubes and pipe punctures. That is why it is important to notify other contractors about the floor heating system and to test the system under pressure.
Air in the system – can lead to noisy operation, corrosion, enhance scale build-up, and blockages.
Freezing – if your home is under construction and subject to freezing temperatures, it is essential to remove water from the system after testing or add antifreeze.
While some products (PEX, manifolds, and fittings) are covered by the manufacturer’s warranty of 25 years, PEX pipes, once installed, can last more than 50 years.
Hydronic floor heating systems are very efficient systems because the heat is transferred in three efficient ways: convection, radiation, and conduction, while with the air-forced systems, it is only convection. This is what provides effective, environment-friendly, and flexible home heating.
And for those suffering from allergies and cold toes, it is a perfect choice.