Is Underfloor Heating Really Green?

Underfloor heating is being championed by suppliers and installers as a ‘green’ system; one that will conserve energy and save you money.

They will tell you that it is more energy efficient than other forms of heating and that it will reduce your carbon emissions.

Of course, the people who want to sell you underfloor heating will provide you with a variety of fanciful figures, but how do you know what is based on factual evidence and what is simply speculation?

Does underfloor heating really conserve energy?

Under the right circumstances and conditions underfloor heating may well be able to conserve energy and save vast amounts of money; but in practice very few of us live in the ‘ideal’ conditions that many companies base their figures on.

So how does underfloor heating impact on energy conservation, heating bills, and our lifestyles in the real world?

This article aims to give you accurate information, and to dispel some of the myths, so you can make an informed decision on the use of underfloor heating in your home.

Does underfloor heating really conserve energy?

The good news is that underfloor heating should save energy in most cases. New buildings which are compliant with building regulations will be more than adequately insulated to ensure that underfloor heating is effective.

When a heating system is installed into an existing property, consideration should be given to the windows, the insulation, and the draught proofing, to make sure the underfloor heating is able to fully heat the room.

The Standard Assessment Procedure, used to calculate a new buildings energy performance, records an energy saving of 5% when using an underfloor system with a condensing boiler, as opposed to a radiator system.

While other research suggests the average saving could be 15%, rising to 40% or more where the heating is linked to a renewable energy source, such as solar heating or a ground source heat pump. 

A typical central heating system is less efficient than an underfloor system, because the heat from the radiators is via convection. The heat rises and creates a very warm layer of air at the top of the room at ceiling level, and a much cooler temperature at floor level.

Some of the heat is wasted through the roof as the room is heated sufficiently to achieve a comfortable temperature lower down.

Underfloor heating radiates heat into the room from the whole surface of the floor, which creates a comfortable temperature from ground level up.

This type of radiated heat is absorbed by people and by furniture and objects in the room, and the same comfort level can be achieved at a 2oC lower temperature than with radiators.

Does it save money on energy bills?

Both wet and electric underfloor heating should reduce energy bills if installed and used correctly. The government are aware that many people are facing fuel poverty this winter in the UK, and estimates suggest that on average, people spend at least 10% of their income on energy.

The cost of energy needs to be reduced and underfloor heating can go some way towards facilitating this.

An electric underfloor system is able to run at a lower temperature in the range of 30-50oC compared to a radiator system, which typically runs at 60-80oC.

A water based system can also run at lower temperatures and can provide further savings as it is usually linked to a gas boiler; gas is cheaper per KWh of heat output than electricity so a wet system is the cheapest to run.

Can it be used with renewable energy sources?

Both types of underfloor heating can be linked to renewable energy sources; this provides an even greater energy saving potential.

Photovoltaic systems, ground source heat pumps, solar panels and wind turbines could all be used to heat an underfloor heating system, and eventually the systems combined could provide free sustainable energy.

Given the right circumstances, underfloor heating is more energy efficient than most types of heating.

Photovoltaic systems use solar heating to power a buildings electric supply, some buildings with a large roof surface are able to produce enough electricity for their demand and are able to sell electricity back to the grid.

While most homes may not have the roof space to power the entire house, an underfloor heating system can be installed with a photovoltaic system to power it, which will result in cheaper running costs.

Wet underfloor heating is suitable for use with ground source heat pumps and solar hot water heating systems. Ground source heat pumps involve the laying of pipes in the garden or somewhere suitable on the property, and extracting the heat directly from the ground.

A water and antifreeze mix is circulated through the network of pipes to draw heat from the ground, which goes through a heat exchanger and into a pump.

A heat pump could provide the hot water for a wet underfloor system exclusively, helped by the fact that it runs at lower temperatures than radiators, offering completely free heating.

Are there any grants available?

The government offer several grants for energy saving measures that people take in their home. Along with underfloor heating, things like insulation, installation of energy efficient boilers, and cavity wall insulation all qualify for benefits under these schemes.

Schemes and grants vary from country to country within the UK, and the eligibility criteria differ for each; while there may also be other local grants available.

In England the scheme is called the Warm Front Scheme, in Scotland the equivalent system is known as the Energy Assistance Package.

In Northern Ireland the scheme is the Warm Homes Scheme, while in Wales it is called NEST.

Summary

Underfloor heating is more energy efficient than most types of heating, given the right circumstances. Well insulated, double glazed and draught proof houses, will conserve energy and save money by using underfloor heating, particularly if it is linked to a renewable energy source such as a ground source heat pump or a photovoltaic system.

In new buildings underfloor heating is becoming the popular choice as the installation costs are no more than for a central heating system, but the running costs in the long term are cheaper, and the energy saving grants available offer further savings.