Underfloor Heating or Radiators?

One of the key decisions to make when specifying a heating system is how you want the space heating to be distributed. The standard, and usually the cheapest option, is to use wall-hung radiators. You would normally place one in each room, maybe two in the large rooms, and the size would be worked out according to a heat-loss calculation. However, a great many selfbuilders plump for underfloor heating (UFH) instead: here, you bury plastic pipework within the cement screed or under a timber floor, and you use the whole floor as a radiator. It’s a little more expensive to install but it’s proved very popular with self-builders over the years because:

• The heat radiates slowly upwards
• It is, therefore, reckoned to be much more pleasant
• There are no hot spots or drafts
• There are no unsightly radiators
• There are energy-efficiency benefits as UFH operates at low temperatures

The downside tends to be that UFH is far less controllable than radiator-based heating systems, so much so that many people leave UFH on 24/7, although with sophisticated controls it is possible to manage two or three temperature regimes. They can take a long time to get a house warm and, having got warm, they take an equally long time to cool down, which can cause overheating. UFH, therefore, tends to suit houses in constant occupation, rather than those where everyone is out all day. One frequent compromise is to fit UFH on the ground floor and radiators upstairs.

There are several issues to be aware of with UFH. The pipes are laid out around the house in separate loops. This way there are no joints below ground. Each loop, or zone, is brought back to a manifold, usually one per floor, which is usually where the controls are located. You can control the individual loops, just as you can control radiators, but if a loop covers two or more rooms, then you have no way of controlling what goes on in each room. More critically, the heat output from UFH varies according to the floor covering: stone and tile transmit heat easily, wood less so, carpet much less so. Thus it is critical to decide on your floor coverings at the outset so that you can ensure that each area corresponds with an UFH zone. If your supplier is on the ball, they will be aware of these issues, but you can’t rely on this.

ABOVE: Controlling underfloor heating relies on zoning your system properly. All zones come back to a central manifold which should be placed in an accessible cupboard

H&R obtained quotes for the two different systems based on floorplans for a 164m² four bedroom home. The underfloor heating quote was provided by Rayotec (01932 784848 rayotec.com); the radiator quote from Feature Radiators (01274 567789 featureradiators.com). The companies did not see heat-loss calculations. Readers should not assume they can exactly match these quotes. Prices exclude VAT.

Further Reading:

• How To Heat Your Home
• Underfloor Heating - Your Questions Answered
• How to replace a radiator