How to maximise your heating system's energy efficiency
Whether you’re just changing a single radiator, or installing a complete central heating system, there are several things to think about to ensure you get the maximum efficiency possible.
With new build homes, it’s unlikely you will need to put in a heating system yourself, however, if you do, then you should approach the architect who designed the house for vital information, such as plans, sections, elevations and thermal insulation characteristics. If your home is not a new build, then it’s a good idea to get a site survey, measure all the rooms in the home and find out the levels of existing insulation.
The amount of insulation within a property is actually a very important point because a well insulated house requires less energy to heat it up. If you are installing a new heating system, it would be a real waste to have an efficient system undermined because of a lack of good insulation. For this reason, in addition to installing the new system, this is a good opportunity to upgrade your insulation.
The next step would be to make some simple heat loss calculations. These calculations are made on a room to room basis, looking at the amount of heat lost through each individual room surface. These figures are then added to the ventilation heat loss figures to give a ‘room total.’ A factor of around 15% should then be added to allow for fluctuations. The final figure should ideally ensure that the desired room temperature can be reached in the shortest time possible once the system is switched on. Once you know the heat loss figures for your home, you can then work out the correct size for your radiators and boiler. (An excellent guide for assisting you with these calculations is the Domestic Heating Design Guide by the Chartered Institute of Building Services Engineers. The purpose of the guide is for heating engineers to understand, specify and design conventional central heating systems, so it is an excellent resource.)
Placement of a radiator is also very important in achieving the best possible energy efficiency and the best place is to install a radiator near the coldest surface in the room. This is usually under or next to a window. Taking into account the amount of insulation and the layout of the room, a single radiator should be able to heat a floor area of around 20m². If the room is bigger then two radiators will be needed, distributed evenly in the room.
Regarding the size of the boiler, this depends on the total heat losses, with an addition of around 10% for domestic hot water and distribution pipe loss. If a combi boiler is being installed then there is no need to factor in calculations for domestic hot water. Further advice on boiler size is given in the Domestic Heating Design Guide and a professional Heating Engineer should also be consulted to ensure you don’t make a costly mistake by purchasing the wrong boiler.
Having temperature controls on your central heating system is vital for preserving energy. Controls can include such things as a digital thermostat, thermostatic radiators valves and a boiler interlock. The more control you have over your heating, including when the heating comes on and off and how hot each individual room can be, the greater your ability to only use heat when and where you need it most. It’s important that the heating engineer assisting you with installing your system either gives you a thorough run-through on how you system and controls work, or at least leaves you with a written guide that you can consult yourself. There is little point in having a brand new heating system, if you are unsure of how it works and how to get the most out of it. Additionally, once the system is fully installed, it’s vital to have your system professionally maintained once per year to ensure your central heating continues to run effectively and efficiently.
Article by Benjamin Clarke