Wet Versus Dry Underfloor Heating: Which One's Right for Your Home?

Article Date: 29 March 2024

Underfloor heating is becoming an increasingly popular option for homeowners looking to warm their houses efficiently and comfortably. This type of heating is great for kitchens and bathrooms, but it can work equally well in any room.

There are two main types of underfloor heating systems: wet and dry. Both offer benefits, so which one is best for your home? This guide examines the key differences between wet and dry underfloor heating to help you decide.

What is Underfloor Heating?

Underfloor heating distributes heat evenly across the floor rather than traditional radiators which focus heat in specific spots. The heat gently rises and evenly warms the room. Underfloor heating pipes or electric wires are laid under the floor with a screed or tiles above. The floor gently radiates heat providing all over warmth.

Wet Underfloor Heating Systems

Wet underfloor heating circulates hot water through pipes laid under the floor. The water is heated by a boiler and pumped through the closed loop pipe circuit. As the hot water moves through the pipes, it heats the floor above. The key components of a wet underfloor heating system include:

Boiler - Provides hot water for heating
Manifold - Controls water flow to different pipe circuits
Pipework - Laid under the floor to distribute heat
Thermostat - Controls temperature

The pipes are usually made from plastic and installed onto a metal mesh. A cement screed is then poured over the pipes providing thermal mass to radiate heat. The typical depth under a floor is 65mm. Wet systems heat water to around 40-50°C.

Benefits of Wet Underfloor Heating:

Even distribution of heat - Underfloor heating provides an even distribution of warmth across the entire floor. This results in consistent heating throughout the room, eliminating cold spots.
Can be zoned for different temperatures - Wet underfloor systems can be separated into different temperature zones. This allows you to set different areas, such as bathrooms or living spaces, to have higher or lower temperatures as needed.
Compatible with renewable heating systems - Wet underfloor heating works seamlessly with renewable energy sources like heat pumps or solar thermal. This makes it a great eco-friendly option if you want to reduce your environmental impact.
High thermal mass provides stable warmth - The thick concrete screed holds significant thermal mass. This helps wet underfloor heating maintain comfortable temperatures for longer periods without rapid heat loss.

Dry Underfloor Heating Systems

Dry underfloor heating uses electric cables rather than hot water pipes laid under the floor. The electric cables warm up when switched on and heat is conducted through the floor. Key components include:

Electric wire with heating element
Thermostat controls
Separate circuits for zoning

The cables are fixed to insulation boards laid on the subfloor rather than embedded in screed. This allows faster heat up and response times. The cables are typically 10-12mm thick under floors. Dry systems heat the cables to around 25°C.

Benefits of Dry Underfloor Heating:

Faster warm up and response - Dry underfloor heating warms up quickly when turned on and responds rapidly to temperature changes. This provides faster heating compared to the lag time of wet systems.
Thinner systems with minimal build height - Dry underfloor requires minimal height, usually around 10-12mm, perfect for renovation projects where build height is limited. This allows installation in spaces with lower floor-to-ceiling heights.
Easy to retrofit in existing homes - Dry underfloor can be retrofitted into existing properties without major disruption to floors. This makes it simpler to install compared to embedding wet system pipework.
Individual room control - With dry underfloor, each room can have its own independent cable circuit and thermostat control. This enables precise control over heating in separate spaces.

Which is Best for Your Home?

So, which type of underfloor heating should you choose? Here are some key considerations:

Type of Subfloor

Wet systems require solid floors like concrete or screed to embed pipes. Dry systems can be installed on wooden subfloors using insulation boards. Wet underfloor heating needs the thermal mass of concrete or screed to effectively radiate heat.

Existing Heating System

Wet underfloor works best alongside a boiler and radiator system. Dry can be standalone electric. Retrofitting wet underfloor can be disruptive, which is an important consideration if you are living in the property. Integrating a wet system with existing heating requires extensive pipework and drainage which can mean significant structural alterations.

Speed of Heating

Dry systems heat up and respond faster as the cables are heated directly. Wet systems take longer to warm the water and screed. The water in a wet system takes longer to come up to temperature which increases heat up times.

Environmental Impact

Wet systems are more eco-friendly when powered by a renewable energy source such as solar panels or a heat pump. Dry systems have higher running costs. The operating costs of dry underfloor heating are higher as electricity is a more expensive energy source per kWh than gas used in boilers.

Build Height

Dry has minimal build height. Wet requires 65mm+ for the screed adding height. The screed layer in a wet system adds non-negligible height which could impact room dimensions.

Costs

Wet systems have higher installation costs but lower running costs. Dry is quicker and cheaper to install but more expensive to run. Labour costs are greater for wet systems as installing the pipework and screed is more complex and time-consuming.

Control

Both types of underfloor heating systems offer thermostatic control. Wet allows room-by-room zoning. Dry has individual control of each cable circuit. With dry systems, each cable circuit can be controlled separately allowing bespoke heating configurations.

Making the Right Choice

The right underfloor heating system depends on your home, budget and priorities. Wet offers affordable warmth but the installation comes with more disruption and it is a better choice if you are renovating or building a new home. Dry systems are simpler and faster to install and come with individual controls.

Talk to us about the best option for your property before making your decision. The correct installation is vital for efficiency. While the upfront costs may be higher, underfloor heating can provide many years of convenient, economical warmth when done correctly. It can also add value to your home!