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Guide to Underfloor Heating Heat Output

September 13th, 2023 | Underfloor Heating Installation
Underfloor Heating Heat Output

Thinking about bringing warmth to your home with underfloor heating? Knowing the heat output of a new heating system is essential in ensuring your space will be heated correctly, so in this guide we’ll walk you through all you need to know about the heat output of floor heating and the factors that can affect this. You’ll learn about:

  • The power of UFH systems and the impact of room size
  • How insulation enhances the heat output of a system
  • The ways in which a thermostat helps to control temperature limits
  • How floor finishes can affect heat output
  • How to prevent thermal blocking from reducing warmth

What is the output of underfloor heating?

Warmup offer both electric UFH and water underfloor heating systems and the maximum power of these systems is normally specified in Watts per square metre. If your floor is well insulated and you have a reasonably modern home, the power usually needs to be between 65-85W/m² to give the required heat output. When it comes to choosing underfloor heating, a 150-200W/m² system is usually specified as the system will not be operational continuously, meaning that if a system is typically running half of the time the room is used, the power provided is half of the Wattage of the system. Meaning that a 150W/m² system usually provides 65-85W/m² per hour. This helps to reduce heat up times and provides a more energy-efficient heating solution.

How will the size of my room affect the heat output?

The size of the heated floor area (which is the area of the floor directly heated by a UFH system) is directly linked to the heat output as the larger the area, the higher the maximum heat output of the system will be. However, the size of the heated floor area in relation to the overall room size affects this output too as the larger the room, the higher the level of heat loss. If the heated floor area is significantly smaller than the overall floor or room size (less than 80% of the area), it may be difficult for a heating system to create enough heat for primary heating unless the home is well-insulated.

In certain rooms, such as bathrooms and kitchens, large parts of the room are covered by permanent fixtures such as baths or inbuilt cabinets. As underfloor heating should not be fitted under permanent fixtures, in these circumstances only smaller parts of the floor surface can be heated which can also affect the heat output. We offer a range of heating solutions specifically designed to bring radiant warmth to bathrooms.

How does floor insulation help with heat output levels?

The heat output of an underfloor heating system can be significantly increased by installing high-quality UFH floor insulation alongside your system. Insulation improves a system’s performance, improving heat-up times and ensuring the heat produced by the system will not escape the space. Depending on what kind of heating system you install, insulation may be fitted immediately below the electric heating mat or wires, used as a surface on which to install water UFH pipes or set below a layer of screed.

Increasing overall insulation levels is a good way to reduce heat loss in your home and achieve a lower heat output requirement. Adding cavity wall, roof and additional floor insulation are all good ways to keep the heat in and will lower the heat output requirement of any heating system. Want to learn more about heat loss in your home? Read our expert article to discover everything you need to know.

Will a thermostat assist with the heat output?

Accurate temperature control is essential in ensuring the correct heat output for your home – the higher the desired room temperature, the more heat output you need to reach this temperature. This is relevant in spaces where the desired room air temperature is relatively high, say 23°C degrees (compared to a typical room temperature of 21°C) as poor controls or poorly installed thermostats can lead to under or overheated rooms. A Warmup Smart Thermostat not only offers accurate control but its innovative technology can also save you money on your heating bills.

Will my floor covering affect heat output?

The relationship between UFH heat output and your chosen floor finish is an important consideration. Not all floor finishes should be heated to the required temperature of floor heating so it’s important to choose flooring that is compatible with this technology.

Dense and solid materials such as tile and stone have a good thermal conductivity meaning that the heat can better transmit from the heating system to the floor surface. Tile and stone can be heated to 29+°C to provide a higher output. Softer floor materials such as wood, laminate and linoleum have a comparatively poor conductivity and should only be heated to 27°C. If your chosen floor finish only allows a floor temperature of 27°C degrees and the heat output requirement is higher than what can be achieved with this, you could consider changing the floor material in order for an underfloor heating system to work as the primary source of heat. If you’re installing floor heating in a small room with a relatively little heated floor area, it is best to choose highly conductive floor finishes. Depending on the heat loss of the area, it may also be necessary to use a secondary form of heating to increase the heat output. In bathrooms, heated towel rails and wall heaters are a great idea as they contribute towards the required heat output.

What is thermal blocking and why does it matter?

Once you have made sure that your new underfloor heating system provides enough heat for a space, it is crucial that you do not block the heat being emitted – this is known as thermal blocking. Insulating and heat-blocking materials, such as thick rugs and heavy, large furniture will significantly hinder the performance of the system. So, it’s best to think about your final interior design touches in your home when installing a new heating system.

Our easy-to-use water underfloor heating quoting tool can calculate the heat loss of your room and will help you find the perfect heating solution for your home. If you have more questions about underfloor heating, visit our UFH Questions and Answers section and find out everything you need to know.

Thinking of installing a new Hydro heating system?

Find out more about installing water underfloor heating systems

Warmup Quoting Tools: instant, accurate, flexible

Warmup offers an extensive range of electric and water floor systems compatible with all floor types, rooms and projects.

Warmup Quoting Tools

instant, accurate, flexible

Quoting Tools: instant, accurate, flexible

Warmup offers an extensive range of electric and water floor systems compatible with all floor types, rooms and projects.

Electric Systems

  • ✓ Ideal for zones less than 25m²
  • ✓ Ideal for single rooms
  • ✓ Does not alter floor levels
  • ✓ Great for renovations

Electric Systems Quote
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Water Systems

  • ✓ Ideal for larger zones over 25m²
  • ✓ Rapid auto heat loss calculations
  • ✓ Compatible with existing central heating systems
  • ✓ Great for new-builds

Water Systems Quote & Buy
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For areas of 24m2 or more, use our full quoting system
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