Top notch

If you order central heating, chances are that your plumber will fit standard panel radiators - but there are other options. If your interior decoration is very important to you, you could choose Bisque radiators, which come in a variety of shapes and colours (available through Ideal Bathrooms, 01-676 4445) but are expensive.

Plenty of choice

You can buy medium-range radiators, which you will find under Radiators or Heating in the Golden Pages (try Hevac at 01-830 1211 and Heating Distributors at 01-837 5144). Many radiator suppliers, DIY shops and bathroom showrooms will have standard panel radiators on show but they will also have catalogues of other types which can be ordered.

Cool surface

You can also buy low surface temp (LST) cover plates that fit over standard radiators. These are useful for, say, children's rooms because they won't burn themselves if they touch the radiator. They can be painted the colour of your wall and so will almost hide the radiator.

Under the window

For a while in Ireland it was thought that radiators shouldn't go beneath windows and many older homes still have radiators on other walls. Yet radiators work by convection so they function best if they're beneath a window. The incoming air helps the heat circulate in the room and the rising heat creates a wall that stops the warm air going out the window. Also, if the exterior wall is damp, the radiator will help dry it out.

Distribute the heat

When radiators are on other walls the room won't be so consistently heated. Instead, there will be a warm patch near the radiator and a cold area by the window. It is also unlikely that you'll put furniture by a window, whereas radiators on other walls stop you putting furniture in those areas. If you do put furniture up against a radiator you stop it working so efficiently as it defeats the purpose of convection.

Boiler types

For a long time there have been two main types of boiler, the conventional one which stores hot water in a tank ready for use and a combi boiler, which heats up the water as it is being used. Now there is a third type.

Condensing boilers used to be mainly for commercial use but now they are supplied to domestic clients as well. They do cost more but have greater fuel efficiency and so cost less to run (as well as being better for the environment). The word condensing applies to the technology used to maximise the boiler's efficiency. It recovers and uses heat that would normally be lost up the flue. One example of a domestic condensing boiler is the Envoy by Potterton (0044 345 697509 or www.potterton.co.uk).

Size matters

Radiators should be sized to fit the room. Often installers will measure where the radiator is going to go and get a radiator to fit the available space, but they should take the whole room into account and calculate the level of heating it needs.

Considerations include the size of windows and height of the ceiling. Radiator manufacturers and suppliers have leaflets and installation manuals about their radiator's output and what size area it can heat, so ask your supplier to let you have a look at these if you are in doubt.

Thermostats

It is very important for radiators to each have a thermostatic radiator valve (TRV) on them. If there is just one thermostat for the whole system, it is often put in the coldest part of the house, the hallway. So the boiler will keep going until this area reaches the right temperature while another room, perhaps a small bedroom upstairs, will overheat. Individual TRVs will enable you to keep each area of your home at an even temperature.

Boiler thoughts

The best place to put a boiler is in the utility room because they make a noise when firing up and the pump is running. God knows who ever had the idea of putting them in bedrooms, they're not conducive to sleep!

The second best place for a boiler is in the kitchen where it can be wall hung or stand on the floor. The floor-standing ones fit under kitchen counters and look like domestic appliances so they can remain exposed. Wallmounted ones can be exposed as part of the kitchen units but if they are hung inside cabinets or cupboards, these should have louvred doors to allow for ventilation and convection. If you have a boiler in the kitchen, you can probably do without a radiator as the boiler is a heat source in itself. And then the hob and oven supply heat as well. In the past boilers were often put in the garden because they were coal or oil fired and people didn't want to bring the fuel through the house.

Although it may seem a good idea, because it frees up space in the home, the pipes from the boiler will have to run through the ground and heat will be lost as it travels into the house.

Boiler size

People get the wrong sized boilers for their homes and this is usually because plumbers tend to use a rule of thumb when sizing the boiler. They will put the same sized boiler in all three-bedroom houses. However, a three-bedroom terraced house will not have the same requirements as a detached or semi-detached house: the latter have three exposed walls so they will lose more heat and the boiler will have to work harder.

Pump it up

A common failing is that pumps are not strong enough to heat the whole building. The size of pump is not determined by the size of boiler but by what we call the static height - how tall the house is. Most three-bedroom houses are fairly standard but pumps will have to be stronger in a large townhouse with a fourth floor. If the pump is not strong enough the hot water will not reach the farthest radiators.

Chew Pieng Ryan is a senior mechanical engineer at Buro Happold in Merrion Square, Dublin. Tel: 01-639 3042.

Emma Cullinan is the editor of Select magazine