Underfloor Heating Guide
Underfloor heating has become increasingly popular providing an energy efficient alternative to the traditional radiator system. There can be a lot to consider before installing it in your home and this guide explains how it all works and what you need to know.
Contents
The Benefits
- Improves comfort
- Better and more even heat distribution
- Improved boiler efficiency
- Rooms stay warmer for longer
- Space saving
- Efficiency and lower cost over time
Underfloor heating has become increasingly popular whether building, extending and renovating the whole-house or even just a single room. The benefits of installing are simple, it improves the overall comfort level in your room because the heat is evenly distributed at a lower temperature and the heat rises from the ground up.
Underfloor heating requires the installation of underfloor heating pipes or thin heating wires in the floor which act as a radiator heating up the room evenly and efficiently. As a result there will be less cold spots around the room. Cold spots are more likely with a traditional radiator system where there can be a temperature difference of up to 4 degrees Celsius in certain areas especially in larger rooms.
With an underfloor heating system your boiler is less likely to overload itself because the temperature needed for it to operate is much lower than a traditional radiator system. Approximately 40 degrees as opposed to 65 degrees Celsius. Underfloor heating takes slightly longer to heat your room but once switched on it stays warmer for longer.
There are also space saving benefits as you will not need any radiators on the walls giving you more flexibility with design choices.
Underfloor Heating Types
There are two main types of underfloor heating. The systems use either water or electricity to provide heat. The heat output of an underfloor heating system should be greater than the heat loss of the room or area it is heating in order for the system to provide enough heat.
It is important to conduct a heat loss calculation to ensure that the system you opt for is suitable. This can be conducted by an architect or a heating engineer who will also help you to choose the correct heat output for the underfloor heating system.
Water
Uses pipes under the floor filled by warm water constantly powered by a boiler, heat pump or even solar thermal energy and embedded within a screed which means it is fitted into the structural sub-floor. Each project can be tailored by the leading floor heating brand, Warmup, during the design phase to get an idea of the system’s performance and efficiency.
Electric
Uses electricity to heat wire under the floor and it does not raise floor levels. You can choose to operate it in different heat outputs from lower to higher wattage depending on the size of your room.
Cost of Underfloor Heating
Installing underfloor heating is typically more expensive than a radiator system. Radiators are cheaper to buy and there is plenty of choice when it comes to size, style and installers. But they are also less energy-efficient because they are prone to overheating. At this point windows may need to be opened resulting in lost energy.
Out of the two main types of underfloor heating, electric underfloor heating is cheaper and easier to install. However, the operating cost can be higher than warm water based underfloor heating. Electric heating systems are perfect for small rooms such as bathrooms, kitchens or toilets where installation of water underfloor heating is much harder and where it’s cost effective for the electric underfloor heating to operate.
Water underfloor heating is also called a wet underfloor heating and this system comes with a higher cost of installation but is much more suitable for bigger spaces such as conservatories where it is cost effective to run. Therefore, it is a popular choice for extensions and new builds.
The cost of installation and operating underfloor heating systems depends on the overall size of your project. Like with any heating system the operational cost also depends on the usage of the system and the level of the heat output. It is best to request a quotation for your project.
Water Vs Electric Underfloor Heating Systems
Electric Underfloor Heating
Electric underfloor heating can come in the form of underfloor heating mats or heating cables. Electric underfloor heating systems that feature the heating mats include foil heaters and the heating cables are decoupling and loose wire systems. Choose the most suitable for your floor and project.
Underfloor Heating Mats
Electric floor heating mats are convenient and energy efficient especially for renovation projects because of their quick and easy installation. Mostly used in regular shaped rooms the mats distribute heat evenly and consistently thanks to their durable heating cables that are already attached onto standard sized mat backing.
These systems will have no impact on floor build-up heights because they feature thin dual core heating elements and a low profile design. Heating mats can generally be used for all floor types but make sure you check which one specifically to use for the type of floor you have. When choosing also check compatibility with the size and heat loss of the room in which the system is being installed.
Sticky Mat System
The StickyMat electric floor heating mat system features a 1.8mm heating wire and a self-adhesive backing for a quick installation. It comes in two different power variants. This system can be used with a wide array of floor finishes including wood, vinyl, tiles or carpeting as long as floor coverings do not exceed 1.5 tog. Always check that your flooring is compatible with underfloor heating.
Foil Heater System
The Foil Heater underfloor heating mat utilises an aluminium foil matting to encompass the heating wires and gently diffuse the heat evenly into the room. It is most suitable for use with floating floor finishes such as laminate and engineered wood. If you are using the foil heater with a softer floor covering like carpeting or vinyl, the heater must be installed alongside the dual overlay system. This acts as a stable subfloor on which the floor will be installed whilst protecting the heater from excessive load-bearing weight.
Underfloor Heating Cables
Heating cables are ideal for rooms featuring many fixtures and are mostly used in new builds or renovation projects. They feature electric floor heating wires that can be installed directly onto or into the subfloor, without the need for a mat backing.
The spacing of the cables is flexible and can be spaced as you wish depending on the required heat output (W/m2). They offer great flexibility for layout design making them the perfect floor heating solution for bathrooms and irregularly shaped rooms. They are suitable for all floor types, are energy efficient and can be installed quickly.
DCM-Pro System
The DCM-Pro heated decoupling system consists of a heating cable and an accompanying membrane which the cable is fitted into. The membrane acts as a decoupling layer which can help prevent damage to the floor finish caused by subfloor movement. This system is the perfect heater to use with stone and ceramic tiled floors.
Loose Wire System
Loose wire is the thinnest electric floor heating cable at just 1.8mm and it is available as a kit featuring the cable, primer, tape and foam roller. It offers fast installation times for irregularly shaped rooms and is ideal for use with stone and ceramic tile flooring. It can also be installed onto insulation boards over concrete subfloors.
Inscreed Cable System
The inscreed cable is ideal for installing within screeded subfloors in new builds. It uses a slower heat-up and cool-down time than other systems, making it suitable for use in rooms which are in constant use. If you are utilising a concrete floor screed this system has been specifically designed to be installed within this subfloor type and can be used with a wide range of floor types.
Water Underfloor Heating
Water underfloor heating, also called a hydronic heating system, uses heating pipes, much in the same way that radiators do, to circulate warm water for heating beneath the floor. The pipes can be connected to your main central heating source. Usually a manifold is used to connect to your boiler and this is the most important part as it controls the direction and temperature of the water. The pipes can also be linked to a more sustainable solar thermal energy or heat pump.
Thermostats are also installed to the system to control the room temperature. Water underfloor heating can usually run at low temperature between 27-31 degrees celsius. However, this ultimately depends on the type and thickness of flooring because the heat needs to easily penetrate through the floor.
Compared with electric underfloor heating, water systems are trickier to install. Therefore, each hydro project is normally designed and quoted for completion by a qualified professional. They will first check your boiler is compatible with the system followed by room design and installation of the pipes. Sometimes extra space needs to be created for the piping and as a result floor levels need to be raised.
Thermostats
Once you have chosen your suitable underfloor heating system you should think about how you wish to control the level of heating. Underfloor heating thermostats ensure an easy and efficient way to effectively heat up your home. There are a wide range of thermostats available from manual and programmable thermostats to remotely accessible Smart thermostats. Make sure you choose the right compatible thermostat that is suitable with the system you have chosen.
Manual
Manual thermostats are basic controllers of temperature more suitable for spaces with infrequent temperature changes.
Programmable
With a programmable thermostat you can program room temperature automatically to your liking and timing. Also available in more advanced energy monitors.
Smart
Smart thermostats are advanced and wifi enabled thermostats saving money and energy.
Underfloor Heating Insulation
It is advisable to install your underfloor heating system with sufficient insulation. In general, there are different products available whether intended for electric or water systems. For electric systems, underfloor heating insulation boards reduce the heat-up time making your system work even more efficiently, saving you money. They work by pushing the heat to the floor level and preventing heat loss to the sub-floor because they sit right on top. The thicker the board the better insulation it provides. However, you will need to consider how this affects the floor height. Therefore, browse for a range of different thicknesses to suit your requirements.
Insulated underlay has been designed to be used with foil heater electric underfloor systems and combined with dual overlay. Insulated underlay pushes the heat upwards making the heating system more effective. It also carries acoustic properties that reduce contact noise and also acts as a moisture barrier. Dual overlay is composed of a base board and top board that is a free-floating subfloor. It protects the heater and provides a secure surface for your flooring.
Installing Underfloor Heating
The installation method of underfloor heating goes hand in hand with the scope of your project. The most suitable solution depends on whether you are installing it in a new build or renovated room or house.
Water underfloor heating for example is easier to install in a new build because floor adjustments can be considered from the start. Each of the electric floor heating solutions are system-specific and come with different features. For full installation guidance please see the installation manuals and technical specifications on each product.
Your chosen type of underfloor heating and its installation method also depends on your flooring type, the subfloor you are installing on and the heat loss calculation. When working out the best solution for you, also think about the room size and type. Seek professional advice to help you calculate desired temperature, heat loss and flooring required. Carpet and solid wood are not ideal whereas engineered wood, laminate and vinyl are. Underfloor heating systems can be fitted by a professional installer or a competent DIYer. All electrical work, including wiring and connecting the thermostat to the heating system, needs to be completed by a part P certified/NICEIC electrician. Consult the heating supplier for installers, find a local plumber who is qualified or contact the leading supplier Warmup for information.