Introduction to Underfloor Heating

Underfloor heating is the means of heating a property via a circuit of pipes or cables laid into the flooring of the building. It is widespread in Europe as one of the more common heating systems, but still has a relatively small market share in the UK; around 5% of the overall heating market.

Underfloor heating provides an even gentle warmth from the floor upwards

With the government aiming to become a zero-carbon society over the next fifty years, and with their commitment to increasing the use of renewable technologies in heating to 12% by 2020, improving energy efficiency is the key trend in property and construction today.

Underfloor heating has seen an increase in popularity in both the commercial and domestic sectors in recent years as builders, developers and home-owners seek the most efficient heating systems.

Incredibly, it has been in use in its various forms for several thousand years. The Romans were the first to introduce underfloor heating on a large scale into Europe, by creating a network of empty spaces and flues in the walls and floors of a building, then lighting a furnace and allowing the warm air to circulate and heat the rooms.

Today’s underfloor heating systems are rather more sophisticated, allowing heating and cooling of different rooms under varying thermostatic controls.

How it works

Underfloor heating systems involve laying a matrix of water pipes, or electric cable under the floor.  If a wet system is used, the pipe work can be connected to the property’s existing heating supply; while an electric system will be connected directly to the electricity supply.  The heat generation is controlled by a thermostat in the room, which is linked to a timer just like a conventional system.

Around 50% of the heat from underfloor heating is radiant heat released slowly by the floor, which is absorbed by furniture and people in the room. As well as providing an even ambient temperature, this reduces heat loss, as very little of this heat is able to escape.

Wet Underfloor Heating

A wet underfloor heating system can be connected to a combi-boiler, gas boiler, or other heat source such as a heat pump or solar. This type of heating is well suited to new buildings as the pipes can be laid in the floor screed, and connected at ‘first fix’, saving time and money on installation.

A manifold assembly will be fitted with the system to control the flow and temperature of the water in the circuit, which usually runs at around 50°C, compared to 70°C for a typical radiator circuit.

Electric Underfloor Heating

An electric system consists of a network of high resistance cables which produce the heat under current. They can be timed to run on a cheap electricity supply, or thermostatically controlled like any other heating system.

Electric circuits are often better for refurbishments to an existing building as they are much cheaper to retrofit than a water system, and have such a low profile; as little as 3mm for some heating cable.  They are generally more expensive to run than water based systems, although initial installation costs are likely to be lower.

Comparisons with conventional heating systems

Most of us are used to a conventional central heating system with radiators supplied by a boiler. This type of system is by far the most common in the UK, but does have its drawbacks.

The heat from radiators rises, and tends to create the hottest space at the top of the room near the ceiling, while the floors remain cold. Underfloor heating creates a more even temperature throughout the room, as heat rises from the entire surface of the floor.

The even distribution of heat means that people in the same room experience the same climate, rather than the person nearest the radiator feeling the most heat. Another advantage to dispensing with radiators is that there is no restriction on where furniture and objects can be placed in the room (except for fixed cupboards which should not be placed above underfloor heating).

Energy efficiency

Underfloor heating is generally considered to be more energy efficient than a conventional central heating system, as the water temperature is lower, and heat loss is reduced.

Underfloor Heating is ideal for new build houses

If correctly installed, an underfloor system will need to distribute less heat to maintain the right temperature; radiators suffer greater distribution losses as the heat rises quickly to the top of the room.

Water underfloor systems also enable condensing boilers to condense more often.

Why do people choose underfloor heating?

Underfloor heating is becoming a much more popular choice in the UK. Many new builds are now including underfloor heating as part of the design, from large commercial projects to individual self-builds.

Reduced heat loss and lower energy bills are driving the move towards underfloor heating, and there are other benefits like the quick and inexpensive installation when fitted in a new build.

For the consumer, the advantages are in the ambience of the room. Tiled floors that are not freezing in winter and a more even distribution of heat make for a much more comfortable climate in the home; this is one of the reasons it is becoming so sought after in the domestic market.

What used to be considered something you would expect to find in the homes of the rich is now available to everyone at competitive prices, making it a viable alternative to conventional heating.

Summary

Underfloor heating systems only make up a small share of the heating market in the UK, but they are becoming more and more popular as people look to improve every aspect of the energy efficiency of their buildings.

Using a network of water pipes or electric cable, the systems heat the full surface of the floor creating an even temperature throughout the room from floor to ceiling.  The type of project or design will determine which type of system can be used, and in the majority of cases underfloor heating will prove to be more energy efficient than conventional central heating.

However, it is essential to calculate heat generation and heat loss for a property before specifying underfloor heating; it is not suitable for every application, and may not be able to provide sufficient heat in all circumstances.