Underfloor heating (UFH) has evolved from a luxury feature to a highly sought-after, efficient, and comfortable way to heat a home. Moving beyond traditional radiators, UFH systems distribute heat evenly across the entire floor surface. Creating a consistent, gentle warmth that permeates the space. This method eliminates cold spots and drafts while often being more energy-efficient than conventional heating.
However, selecting the right underfloor heating system for your specific house can be a complex decision. It requires careful consideration of your property type, construction, floor finish, energy source, and budget. This comprehensive guide will break down the primary types of UFH, their suitability for different scenarios. And the critical factors you need to weigh before making a final choice.
The Two Main Contenders: Wet vs. Electric
Underfloor heating systems are broadly categorized into two main types: wet (hydronic) and electric (dry). Understanding the fundamental difference between these two is the first step in the selection process.
1. Wet (Hydronic) Underfloor Heating Systems
Wet systems circulate warm water through a network of pipes (typically made of PEX or Pert) installed beneath the floor. The water is heated by a boiler, heat pump, or even solar thermal panels, making them highly versatile in terms of energy source.
- How it Works: The boiler or heat pump warms the water, which is then pumped through a manifold that distributes it evenly through the piping loops embedded in the floor.
- Best Suited For:
- New Builds/Major Renovations: Installation is easiest and most cost-effective when the floor structure is being laid or significantly altered.
- Whole-House Heating: Hydronic systems excel at heating large areas and providing the primary heat source for an entire home.
- Energy Efficiency Focus: They run on low water temperatures (often 35-50°C), making them exceptionally well-suited for pairing with heat pumps (Air Source or Ground Source) for maximum energy savings.
- Pros: Lower running costs, highly energy efficient, works well with renewable energy sources, long lifespan.
- Cons: Higher initial installation cost, more complex and time-consuming installation, increases floor height (unless a low-profile system is used), slower heat-up time.
2. Electric (Dry) Underfloor Heating Systems
Electric systems use heating cables, mats, or foils installed directly under the floor finish. These systems connect to the main electrical supply and convert electricity into heat.
- How it Works: Thin electric cables, often pre-spaced and woven into a fiberglass mesh mat, are laid out and connected to a thermostat and the electrical circuit. When the thermostat calls for heat, electricity flows through the cables, generating warmth.
- Best Suited For:
- Single Rooms/Small Areas: Perfect for heating bathrooms, kitchens, or conservatories where you need supplementary or localized warmth.
- Retrofit Projects: Since they are very thin (often less than 3mm), they are ideal for installation on top of existing subfloors without significantly raising the floor height.
- Quick Installation: Electric mats are generally much faster and simpler for a qualified electrician to install.
- Pros: Low initial cost, very quick installation, minimal floor height build-up, fast heat-up time, excellent for retrofits.
- Cons: Higher running costs (as electricity is typically more expensive than gas/water heating), less suitable for whole-house heating in high-demand climates.
Key Factors Guiding Your Decision
Once you understand the basic difference between wet and dry systems, you need to assess your home’s unique characteristics against these critical factors:
1. The Floor Construction and Height
This is perhaps the most crucial factor.
- Solid Floors (Concrete/Screed): Wet systems are most effective when embedded in a thick layer of screed (a cement mixture). The screed acts as a thermal mass, storing and radiating the heat slowly and evenly. This is standard for new builds.
- Timber/Suspended Floors: Both wet and electric systems can be used. For wet systems, special joist plate systems (which sit between the floor joists) or low-profile overlay boards are used to minimize floor height increase. Electric systems, due to their thinness, are generally the easiest option here.
- Floor Height Constraint: If adding even a few millimeters to your floor height is problematic (e.g., at doorways or stairs), a foil electric system (for laminate/wood) or a thin electric cable mat is the best solution.
2. The Final Floor Finish
The material you choose for your floor finish will affect the system’s performance and maximum temperature.
- Best Conductors (Highest Heat Output): Tiles and Stone are the most efficient floor coverings for UFH as they conduct and retain heat exceptionally well.
- Good Conductors: Engineered wood is generally suitable, but the temperature must be carefully controlled to prevent warping.
- Poorer Conductors: Thick carpets and some laminate floors can limit heat output. Ensure any carpet or underlay has a low tog rating (ideally below 2.5) to allow heat to pass through efficiently.
3. Energy Source and Running Costs
Your choice of heating system must align with your energy strategy.
- Wet Systems and Heat Pumps: If you are committed to renewable energy and using a heat pump, a wet UFH system is non-negotiable. Heat pumps operate most efficiently when heating water to low temperatures, which is exactly how hydronic UFH is designed to run.
- Electric Systems and Tariffs: Electric systems can be cost-effective for small areas, especially if you utilize off-peak electricity tariffs (though this is less common now) or if you have a source of free solar power during the day.
4. Heat-Up and Response Time
Consider how quickly you need the system to respond to changes in temperature.
- Slow Response (Wet Screed System): A wet system embedded in a thick screed takes several hours to heat up and cool down. This is ideal for continuous heating where the temperature is kept stable throughout the day.
- Fast Response (Electric or Low-Profile Wet): Electric mats and low-profile wet systems (which use minimal screed or boards) heat up and cool down quickly. This is better for rooms that are only used intermittently, like a home office or a bathroom in the morning.
Conclusion: Making the Final Choice
Choosing the correct underfloor heating system is a balance between initial investment and long-term running costs, constrained by the physical characteristics of your home.
| System Type | Best Application | Key Consideration |
| Wet (Hydronic) | New builds, whole-house heating, paired with heat pumps, solid concrete floors. | High initial cost, low running cost, slow response time. |
| Electric (Dry) | Single rooms (bathrooms/kitchens), retrofits, properties with height restrictions. | Low initial cost, higher running cost, fast response time. |
For homeowners undertaking a large renovation or building from scratch, a wet system offers unparalleled comfort and the lowest long-term operational costs, especially when paired with a highly efficient heat pump. For those wanting to upgrade a single room with minimal fuss and disturbance, an electric mat system provides a quick, comfortable, and affordable solution.
Always consult with a qualified UFH specialist and a plumber or electrician. They can perform a full heat loss calculation for your property, ensuring the chosen system is correctly sized and installed to meet the required warmth output for your specific environment. A correctly installed system guarantees decades of efficient, silent, and luxurious warmth, transforming the feel of your home.
Would you like to explore the specifics of a low-profile wet underfloor heating system for a small apartment renovation?