Here’s a practical comparison of underfloor heating which offers a compelling alternative to traditional radiators. It delivers even warmth, frees up wall space, and can improve energy efficiency. However, choosing between an electric (dry) system and a water-based (wet) system is a critical decision. The right choice depends on the scope of your project, your budget, and how you plan to use the space.
The Fundamental Difference
The distinction lies in how each system generates heat. Electric underfloor heating consists of a long wire or heating mats laid beneath the floor covering. When switched on, the wire heats up, warming the floor and the room above. While water underfloor heating, conversely, uses a network of pipes filled with warm water circulated from your boiler or heat pump.
Installation and Upfront Costs
Electric systems are generally cheaper and less disruptive to install. They have minimal impact on floor height and can often be retrofitted in a single room, such as a bathroom, in under a day. Installation costs for an electric system in a standard bathroom typically range from £250 to £500 for parts and labour. In contrast, water systems are more complex and disruptive to install. They usually require removing the subfloor to lay pipes, which adds significant time and cost. Installing a wet system in a single bathroom can cost between £600 and £1,200 or more due to the extra plumbing and manifold requirements. For a whole-house installation, water systems are the norm but represent a substantial upfront investment.
Running Costs and Efficiency
This is where the two systems diverge most significantly. Electricity is considerably more expensive per kilowatt-hour (kWh) than gas, which is the most common fuel for wet systems. As a result, electric underfloor heating is much more expensive to run. It is best suited to small, intermittently used rooms like bathrooms or en-suites. Water underfloor heating is highly cost-efficient for larger areas because it operates at a lower flow temperature—typically around 35-45°C compared to 60-75°C for radiators. This lower temperature allows it to be up to 25% more efficient than radiators and makes it an ideal partner for modern heat pumps, delivering low running costs. For larger spaces or whole-house heating, the long-term savings of a wet system can offset its higher installation cost.
Responsiveness and Comfort
Electric systems heat up quickly, typically reaching temperature in 20-30 minutes. This rapid response makes them excellent for rooms where heat is only needed for short periods. Wet systems, particularly those embedded in a thick screed, take much longer to warm up—often two to four hours—but they retain heat for longer, providing a more stable and consistent temperature. Both of these systems are popular with Radiator Outlet customers across the UK. With winter approaching, this is an ideal time to consider investing in this type of product.
Regulatory Considerations
It is important to be aware of UK regulations when installing underfloor heating. Bathroom electrical work, which includes electric underfloor heating, is notifiable under Approved Document P. This means the work must be carried out or signed off by a Part-P registered competent person. Furthermore, any new heating system in England and Wales must meet the energy efficiency requirements of Building Regulations Part L. Wet underfloor heating is often favoured in new builds and major renovations for its compliance with these low-carbon standards and its compatibility with heat pumps.
Conclusion: Which One to Choose?
The choice ultimately depends on your specific project. Electric underfloor heating is the practical, cost-effective choice for single rooms, especially smaller spaces like bathrooms or kitchens where it can be easily retrofitted. Water underfloor heating is the superior investment for whole-house heating, new builds, and major renovations, offering significantly lower running costs and future-proofing your home for a low-carbon heating system.
