Share:
​Underfloor heating (UFH) is rapidly becoming the preferred solution for modern bathrooms, evolving from a simple luxury to a practical and energy-efficient home upgrade.
The appeal is understandable: it transforms the one room often subjected to the shock of cold, hard tiles into a warm, inviting space. By replacing bulky radiators with invisible heating elements, underfloor heating not only enhances comfort but also offers unparalleled design flexibility.
This quick guide from The Bathroom Showroom highlights the numerous benefits of installing underfloor heating in your bathroom, exploring everything from the sheer indulgence of a warm floor to critical factors such as energy efficiency, running costs, and the choice between electric and wet systems.

The Benefits of Underfloor Heating for Bathrooms

​
Underfloor heating is an increasingly popular heating solution for bathrooms, offering a blend of luxury, space-saving design, and energy efficiency.
1. Comfort and Luxury
  • Detail: Provides consistent, gentle, radiant heat from the floor up, effectively eliminating the shock of cold tiled floors in winter.
  • Detail: The gentle warmth also quickly dries wet floors and bath mats, which helps reduce slip hazards and minimises the risk of mould and mildew.
  • Practical Tip: Use a programmable thermostat to schedule heating times so your bathroom floor is warm precisely when you wake up or get home.
2. Space Efficiency & Design Freedom
  • By removing the need for large radiators or towel warmers, underfloor heating opens up wall space.
  • Detail: This option provides more room for storage and decoration, allowing you to create a sleek, minimalist, and uncluttered aesthetic.
  • Practical Tip: Plan your new bathroom layout carefully to maximise the newly available wall space and take advantage of the design freedom.
3. Energy Efficiency
  • Detail: UFH systems operate at a much lower temperature (typically under 29°C) than traditional radiators (65°C to 75°C) to achieve the same level of comfort.
  • Detail: This lower operating temperature can reduce overall energy consumption compared to traditional high-temperature heating systems.
  • Tip: Always use special insulation boards under the heating system to prevent heat from escaping and help it work more efficiently (this can increase the efficiency of electric systems by up to 50%).

Is Underfloor Heating Expensive to Run?

​
Financial Comparison: Electric vs. Wet UFH 
  • Installation Cost (Per m²)
Electric Underfloor Heating (Bathroom): Cheaper to install, typically costing £50-£85 per square meter.
Wet UFH (General): More expensive to install, typically costing £85−£110 per m2.
  • Running Cost
Electric UFH (Bathroom): Higher per hour/day, but is cost-effective for short, intermittent use (e.g. the bathroom morning rush).
Wet UFH (General): Lower per hour/day, making it cheaper to run over a long, continuous period.
  • Return on Investment (ROI)
Electric UFH (Bathroom): The ROI is primarily derived from the comfort, luxury, and speed of installation in a small, retrofit project. It is also viewed as an attractive feature that can add value to a property.
Wet UFH (General): The ROI is based on significantly lower long-term running costs and the system's exceptional longevity (often 50+ years), especially in larger installations or new builds.

Legislation and Building Regulations (UK)

In the UK, underfloor heating installations must comply with specific parts of the Building Regulations to ensure safety, efficiency, and proper functionality.
  • Part L (Conservation of Fuel and Power): This is the most relevant regulation, focusing on the energy efficiency of heating systems. Key requirements for UFH include:
Adequate Insulation: Mandating minimum insulation values beneath the heating elements to minimise downward heat loss.
Heating Controls: Requiring thermostats and timing devices to enable zoned and scheduled temperature control, thereby improving efficiency.
Low Temperature: New heating systems must be designed to operate with a maximum flow temperature of 55°C, a requirement that UFH easily meets (typically running at around 45°C or less).
  • Electric underfloor heating must adhere to safety regulations, including the use of a special safety switch (RCD) and compliance with specific wiring standards. A qualified electrician must connect the system to your power supply.
For a detailed understanding, consult the official guidance on the government website, such as Approved Document L (Conservation of fuel and power, Volume 1: Dwellings).

Underfloor Heating Decision Checklist for Your Bathroom

​
Choosing Between Electric (Dry) and Hydronic (Wet) UFH
What is the size of your bathroom?
For small areas (typically under 15m2), Electric UFH is the perfect choice. For larger spaces, the Hydronic (Wet) UFH system becomes more cost-effective to run over the long term.
Are you planning a retrofit or a full renovation/new build?
If you are doing a floor upgrade or minor retrofit, Electric UFH is ideal. Its thin mats/cables result in a minimal increase to floor height and cause less disruption. If you are undertaking a full renovation or new build, Hydronic UFH is generally preferred, though installation is more complex and often requires pipes to be laid in screed, which significantly raises the floor level.
Will you heat your bathroom occasionally or continuously?
If your priority is occasional, quick heat, Electric UFH is best. It heats up quickly (20-30 mins) and has a lower initial cost. However, running costs are higher if used continuously. Hydronic UFH has a higher initial cost but is more energy-efficient for continuous or whole-house heating and has lower running costs, especially when connected to an efficient boiler or heat pump.
What type of flooring will be installed?
Both systems work well with most floor finishes. Tiles and stone are the most effective as they conduct and retain heat best. For other finishes, such as wood or carpet, ensure they are rated for use with UFH and have a low tog value (ideally 1.5 tog or less) to ensure the system operates efficiently.
Will you install the UFH system yourself or hire a professional to do it?
Electric UFH is considered DIY-friendly for the physical installation of the mats/cables. Crucially, it must be connected to the mains by a qualified electrician. Hydronic UFH is a more complex plumbing system, and professional installation is highly recommended or required, typically needing a qualified plumber or Gas Safe engineer for the pipework and boiler connection.
Do you want individual control for the bathroom UFH?
Yes. Electric UFH is excellent for zone control, allowing you to easily heat the bathroom independently with a smart thermostat. Hydronic UFH can also be zoned and use smart thermostats, but it requires a manifold system and extra planning to separate the bathroom from the whole-house heating.
​
Critical Questions for Your Installer or Supplier
How will the UFH system affect my floor height?
You must ask the installer how much the system will raise your final floor level. Electric systems are thin, but hydronic systems, especially when installed in screed, can add significant height, which impacts doors, skirting boards, and adjoining floors.
Do I need special insulation?
Yes. It is highly recommended for all systems, particularly electric, to install insulation boards beneath the UFH. This prevents heat loss downwards, significantly improving warm-up time and energy efficiency.
Where should the controls and sensors be placed?
Confirm the placement of the thermostat and floor sensor. Thermostats are often not permitted to be placed inside the bathroom (they must be located in an adjacent room). The floor sensor must be correctly positioned between the heating elements. You should also request heat-loss calculations for your room to ensure the system can produce enough heat to replace a radiator if desired.
What is the total cost, and what will it cost to run?
Always get a fixed quote for the total estimated cost, including all materials, the thermostat, insulation, and labour. Also, get a realistic estimate of the running costs per month for your bathroom size to accurately compare the long-term expense of electric vs. hydronic UFH.
What safety and warranty checks are required?
Ask about the product warranties and what specifically voids them (incorrect installation can void the cover). Confirm the required professional accreditations for the installer (certified electrician for electric; certified plumber/engineer for hydronic). Finally, if you are planning a wet room, ensure the system is rated for waterproofing and complies with all relevant electrical safety zones in the bathroom.

A Smart Investment in Bathroom Comfort and Value

Underfloor heating in the bathroom is a transformative upgrade that delivers tangible benefits in terms of comfort, design, and energy efficiency. From eliminating the dreaded cold-floor shock and reducing mould risk to freeing up precious wall space for a clean, minimalist aesthetic, the advantages are clear.
Installing underfloor heating in the bathroom, combined with proper insulation, provides a modern and energy-efficient heating solution for the home. Reviewing the practical advice and decision-making tips outlined can help ensure an efficient and valuable upgrade, enhancing daily use and increasing long-term property value.
For further help with choosing the best products to keep your bathroom warm this season, book an appointment with The Bathroom Showroom. Experts in all things bathrooms, we can help turn your dream bathroom into a reality.