Underfloor heating is the kind of luxurious feature that everyone wants in their bathroom and kitchen. But for homeowners renovating existing properties, particularly older homes, the major disruption of retrofitting a traditional underfloor heating system, such as digging up floors, pouring screed, and significantly raising floor levels can turn a dream into a nightmare.
One alternative is to consider an electric system, but this may not always be the most cost effective solution, which is when overlay underfloor heating may be a suitable solution.
Designed to work in the same way as a traditional system, but without the disruption, here's what to consider if you're thinking of it for your home renovation.
Article continues belowHow does overlay underfloor heating work?
Rather than being embedded within the floor structure, overlay underfloor heating systems are designed to sit directly on top of the existing subfloor and beneath the finished floor surface.
They use low-profile, pre-routed boards, typically made from high-density insulation materials, which house smaller diameter pipework, allowing the system to operate effectively without the need for thick screed. This approach dramatically reduces issues with installation, and removes the worry of floor height build-up, which with overlay systems typically sits at around 15-35mm.
Overlay underfloor heating is becoming increasing popular because it’s cheaper than traditional underfloor heating system costs, and designed to simplify installation while maintaining strong performance.
And, much like a traditional system, “correctly installed and zoned overlay underfloor heating will result in reduced energy usage and a lower heating bill,” says Sam Jump, head of business development at Wunda Group. “Our low temperature water-based system allows for efficient heating where you want it, and when you want it, offering an energy-efficient heating solution.”
Sam Jump is the Head of Business Development for Wunda Group. He has spent over a decade of leading product development and industry expertise for the British-owned heating and energy system brand.
When should you use overlay underfloor heating?
Overlay underfloor heating is ideal for retrofits and renovations
Overlay underfloor heating is particularly well suited to retrofit and home renovation projects, where removing existing floors, or significantly increasing floor height isn’t practical. It works especially well when retrofitting underfloor heating into a property with existing concrete slabs, in kitchens and bathrooms where fast heat-up times are desirable, and in renovations that use hybrid heating systems.
Overlay systems also offer good compatibility with other modern heating systems such as heat pumps, explains Sam Jump.
“Air source heat pumps generally heat the water to about 35 - 50°C, so it’s important to make sure you are pairing your heat pump with a low temperature central heating system, such as overlay underfloor heating that can utilise lower temperature water, but still heat the home comfortably.”
Benefits of overlay underfloor heating
Overlay systems avoid the need for extensive structural work, and in most cases the process involves laying pre-routed boards onto a prepared, level floor, then pressing the pipework into the channels before connecting the system to a manifold.
“The thought of installing underfloor heating can seem daunting, especially doing it yourself. But with guided technical support, or the help of a professional, the system can be set up correctly for your home,” confirms Sam Jump. “What many might not realise is that the entire downstairs footprint of a three-bedroom home could be retro-fitted over the course of a weekend with minimal disruption.”
This reduced disruption is one of the system’s biggest advantages, particularly for homeowners living in the property during renovation.
Performance of overlay systems is also very good. Because the heating elements sit much closer to the floor surface than in traditional screeded systems, they respond far more quickly.
“Thanks to the rapid response of the system, heat is distributed evenly from across the entire floor surface, turning floors into giant radiators that start to heat rooms in just 30 minutes,” says Sam. “This provides a consistent, evenly spread heat, from the floor up.”
Suitable for a range of flooring types
Overlay systems are also designed to work with a wide range of flooring types. Tiles are particularly effective due to their ability to conduct heat efficiently, while laminate and engineered wood can also perform well if installed correctly.
Underfloor heating with carpet is possible, but the combined tog rating should typically remain below 2 to avoid restricting heat output.
Low-risk and low-maintenance
When installed correctly from the outset underfloor heating is widely regarded as a low-maintenance, long-term heating solution – with no joints under the floor from which water could leak and very little maintenance besides an occasional purge of the central manifold.
“Electric underfloor heating requires virtually no routine servicing, and while water-fed underfloor heating benefits from occasional checks such as reviewing manifold pressure levels, ensuring flow rates are balanced, and confirming there is no air within the system by bleeding underfloor heating, it is still minimal when compared to other systems,” says Jade Pederigan, retail marketing executive at Warmup.
Jade Pederigan is a Retail Marketing Executive at Warmup, the World’s best-selling floor heating brand, working on underfloor heating products across the UK market.
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How much does overlay underfloor heating cost?
Costs for overlay underfloor heating will naturally vary depending on the system type, specification and installation method.
“For a water overlay system, material costs commonly start from around £40 - £60 per m² depending on the panel type and specification, with additional costs for the manifold and controls,” explains Jade Pederigan.
“Installation for a 40m² area typically takes 2 - 3 days with labour charged at around £200 - £300 per day, giving an estimated installation labour cost of £400 - £900.”
Could an electric underfloor heating system be cheaper?
Electric underfloor heating systems, with entry-level heating elements can start from around £15 per m². However a full specification including insulation boards and a smart thermostat will increase overall material costs. The biggest opportunity for saving money when installing overlay underfloor heating comes from DIY installation.
“You can reduce labour costs considerably if you are confident preparing the subfloor and laying panels or membranes,” says Jade Pederigan. “However, electrical connections, testing and commissioning must always be completed by qualified professionals to ensure safe operation and warranty protection.”
FAQ
Can you use it in conjunction with radiators?
In short, yes. Homeowners can choose to install underfloor heating on the ground floor while retaining radiators upstairs. This can be even more beneficial when combined with renewable heating.
“Water overlay UFH works particularly effectively with air source and ground source heat pumps, as both technologies operate at lower flow temperatures (typically 30 - 40°C). This improves overall system efficiency and can reduce running costs compared to traditional radiator-only setups,” says Jade Pederigan.
Overlay underfloor heating removes many of the barriers associated with traditional underfloor heating making it a practical option for a wide range of renovation projects.
With minimal disruption, fast response times, compatibility with modern renewable and hybrid heating systems, and low maintenance requirements, overlay systems offer homeowners a way to significantly upgrade their heating system, without the need for major structural work.
For more advice on using and installing underfloor heating, make sure you know the main underfloor heating mistakes to avoid, and find out what is the optimum temperature for underfloor heating.
