Design: The right radiator

So the first chill of autumn has sliced its way through the air and thoughts are turning to central heating. For most of us, that means firing up a series of ugly white steel boxes that we try to hide behind covers. But those days are over, and the radiator fetish is spreading among consumers and designers. Radiators now come in all sorts of shapes, materials and colours – round steel plates, hot boxes, even stone and clear glass models – partly because of the need to find more eco-friendly solutions and partly because of the wealth of options available. By answering a few simple questions, you can find something to fit the bill.

How big should my radiator be?

This is the first crucial step. Ask a plumber to calculate this before you buy. Or do it yourself in watts or British Thermal Units (BTUs). Work out the volume of the room in cubic metres (length x height x width) then for sitting rooms multiply by 50, bedrooms 40, halls, stairs and kitchens 30 and bathrooms 90. Add 15 per cent for north-facing rooms and 20 for French windows, or deduct 10 per cent for double glazing. If your house is less than 20 years old, take off 30 per cent. That number is the size of radiator you need in watts. Multiply by 3.412 for BTUs.

What is the greenest heating choice?

Swap stainless-steel radiators for recycled aluminium. They use a tiny amount of water, so heat up quickly and reduce energy use. Then fit thermostatic radiator valves, which automatically switch each radiator off as they reach the desired temperature, so the hot water can go to the other radiators instead. If you use a timer system, energy is only used when necessary.

What are radiators made from?

Katie Findlay, co-owner of Feature Radiators, the biggest supplier of specialist contemporary and traditional radiators in the UK, gives her verdict.

Aluminium: Lightweight, easy to install, and gives terrific output for the size. Quick to heat up, too, but quicker to cool down. Aluminium is also reasonably priced and popular in modern and period homes as the flat-fronted panels make them discreet.

Cast iron: If you want a reclaimed original cast-iron Victorian radiator, you'll have to find the perfect size and have it restored, and you risk damaging your boiler. It's hard to assess its output to know if it's the right size for the room, and it can be hard to spot leaks. You also have no recourse if you bought it as seen from a salvage yard. If you buy reproduction, it will come with a guarantee, and you can have have it professionally spray-painted.

Cast iron takes a while to get going but retains heat very well. You need to turn them on 90 minutes before you want to use the room, but you can turn them off earlier. They also tend to give a good all-round heat rather than the quick, intense burst you get from steel, so are great in old houses.

If you have cast iron, add a third short midday heating period to reduce that long heating-up time.

Stainless steel: Good for bending into sexy shapes, this is often the contemporary material of choice. It lasts well and is very efficient. But if you go for an unusual look, think about whether you can live with it for a long time.

Stone: Natural materials are coming through now. Findlay does one in marble, which is fantastic for retaining heat and looks great in a bathroom. You can have it with a rail attached for a towel.

Glass: Glass radiators are electric but come with their own thermostats and have no visible pipes or wires. "It just looks like a window, but it heats up," says Edd Payton from the Glass Radiator Company. The glass is covered with a clear film that does the heating. Or you can have one that looks like a mirror. They are expensive (about £1,000) but only cost around 2p an hour to run. They are popular in France, where electricity is cheap.

Do I have to put them under the window?

Radiators are usually put under windows since they work best in the coolest part of the room, but that's not necessary if you work out where you want your furniture. If you have floor-length curtains, it might not be sensible to have the radiator under the window as it will be hard for the heat to push its way back into the room. Or trim the curtains.

Can I paint my exisiting radiator?

You can, but you won't get the professional job that spraying would do. Findlay recommends using car paint, which, she says, is perfectly adequate for the job. "It's designed to cope with extremes of temperature and has be tough enough to withstand a great deal of abuse," she says. "You can use emulsion to match the walls, but it will crack and peel."

Should I buy electric radiators?

You would use these if you have built an extension and didn't want to go through the upheaval of adding to your existing central heating system, or if you were in a listed building and weren't allowed to install pipes. Or if you needed extra heat in a specific room, if say, an elderly parent was coming to stay. Many radiators come in freestanding electric versions.

Do heated towel rails work?

Yes, if you buy the right one. You do need to consider if it is the sole source of heat for the room because if you cover it in towels then there won't be much space left for heating the room. But if you are going to have a radiator as well then the dedicated rails are perfect for warming the towels.

www.featureradiators.com; 01274 567 789 (nationwide delivery)
www.theoldradiatorcompany 01233 840 455
www.glassradiators.co.uk; 08700 100 602
www.diy.com; 08700 101 006 (designer radiators from B&Q)
www.marbleheating.co.uk; 08452 300 877
www.radiatingstyle.com; 08700 723 428