Underfloor Heating Cost Calculator
Instantly estimate the daily, monthly, and yearly running costs of your electric or water underfloor heating system based on room size, insulation, and energy tariffs.
System & Room Details
Enter your room dimensions and heating specifications
Insulation quality drastically affects heat loss and running costs.
Enter your electricity rate for electric systems, or gas rate for water systems.
Running Cost Estimation
Daily, monthly, and yearly energy expenses
Enter your room details and system specs above, then click Calculate Running Costs.
Typical Heat Output & Insulation Factors
The required wattage per square metre varies based on your room’s insulation and the type of underfloor heating system installed.
| Insulation Level | Electric (W/m²) | Water (W/m²) | Estimated Heat Loss |
|---|---|---|---|
| Poor (Older home) | 200 W/m² | 100 W/m² | High heat loss, requires more energy |
| Average (Standard) | 150 W/m² | 70 W/m² | Moderate heat loss, typical for most homes |
| Well Insulated (New build) | 120 W/m² | 50 W/m² | Low heat loss, highly efficient operation |
Underfloor Heating FAQ
Everything you need to know about running costs, efficiency, and choosing the right system for your home.
Underfloor heating is generally very efficient. Because it heats the entire floor surface, it operates at a lower temperature than traditional radiators while providing the same level of comfort. Well-insulated electric systems typically cost between £10 and £20 per month to run in a standard bathroom, while water systems connected to a gas boiler are often cheaper to run in larger spaces.
Electric underfloor heating is much cheaper and easier to install, making it ideal for smaller rooms or retrofits. However, water (hydronic) underfloor heating is significantly cheaper to run in the long term, especially for whole-house heating or large open-plan areas, because it uses your existing central heating system which is more efficient than electricity.
Yes, insulation is absolutely critical. Without proper insulation, a significant amount of heat will be lost downwards into the subfloor. High-quality insulation boards (like XPS or cork) direct the heat upwards into the room, reducing heat-up times by up to 50% and drastically lowering your running costs.
Electric underfloor heating systems heat up very quickly, typically reaching the desired temperature in 20 to 40 minutes. Water (hydronic) systems take longer, usually between 2 to 4 hours, because they are heating a larger volume of water and the surrounding screed or concrete.
Yes, both electric and water underfloor heating can be used as a primary heat source for an entire home. Water systems are the most common choice for whole-house primary heating due to their lower running costs, while electric systems are often used as primary heat in smaller, well-insulated rooms like bathrooms.