Why zone your heating?
Posted by Alex Barrett on 24 February 2017 at 10:40 am
Central heating systems are great for keeping the house warm during the cold winter months. Even in the spring and summer they can frequently come in handy. But it does cost a lot of energy to heat your home. As much as 60% of domestic energy consumption is used for space heating . So how can we reduce this energy bill, without making our houses unpleasantly cold?
Temperature zoning systems are one solution. In many houses heating is provided by a central boiler which pumps heat through a series of radiators. The temperature in the house is controlled by a central thermostat, which constantly measures the temperature in the house. The thermostat is set to keep the temperature at a certain level. When it drops below this point the boiler will switch on to provide more heat, when the house is too hot the thermostat will instruct the boiler to shut down for a while.
The problem with this system is simple. Where do you put the thermostat so that the temperature it measures will be representative of the entire house? If you put it in your cosy living room then that room will stay the right temperature, but colder regions of your house might never get warm enough. Put it in a draughty corridor and your warmer rooms may become sweltering as the boiler tries to get the hallway up to temperature.
In general we have a tendency to overheat our houses. Throughout most of history space heating was much less reliable than it is today, it was usually provided by the fireplace in frequently used rooms, or by the kitchen range. The family would spend most of their time in the warm space, and accept that extra blankets or thicker socks were needed in other parts of the house.
Nowadays we have the ability to make sure that all of our rooms are at a comfortable temperature. However not all rooms need to be heated to the same degree. Living rooms and bedrooms need to be warm, but do halls and utility rooms? The kitchen will be warmed up by the oven and appliances, so may not need as much heating from the radiators.
By creating zones of different temperature you can ensure that each part of your house has the right level of comfort. Frequently what is comfortable for one person will be too hot or too cold for others. The way we heat our homes has changed from a former emphasis on heating people to heating the air within spaces. Most people can cope with a temperature a few degrees lower than the 18oC that is typical of modern houses  but in a very well insulated house it should be affordable to keep at least one room at a very comfortable 21oC whilst the house is occupied.
Creating a set of temperature zones is easy to do. Many radiators are fitted with thermostatic valves [4, 5]. These control the flow of water through that radiator, and therefore the temperature of the room. They don’t affect whether the boiler itself switches on and off, just how much of that heat is channelled to each room. Decide on the right temperature on a room by room basis. This way you can ensure that you are not spending excess energy to heat a room that is hardly ever in use, or which you only pass through on your way to another area.
A survey by Which? Magazine found that around half of houses with central heating didn’t have thermostatic valves, so although this is a very easy solution it isn’t in wide enough use .
Thermostatic valves are a simple solution, but far more sophisticated systems are also available. A range of “smart” heating controls, such as Nest  and Hive  can be used to optimise heating use throughout the house . These smart systems can learn how you use your living space, and monitor the comings and goings of residents to ensure that the heating matches their behaviour.
However you choose to control your space heating, zoning is a great way to cut your energy usage and save on heating bills.
- Griffiths, N. (2007). Eco House Manual. Yeovil: Haynes Publishing.
- Low Tech Magazine
- BBC news
- Which? Magazine
- The Guardian
Image credit: Alex Barrett 2016
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