Heating controls

In an ideal world every room in your house would always be at exactly the right temperature, depending on whether you were using them or not. The right controls have the potential to enable this to happen (the rest is down to ventilation and insulation), whilst reducing your bills and emissions

Electric water heater controls

Cylinder thermostats (from £20) prevent the water stored in your cylinder being hotter than it needs to be - the immersion heater will turn off once the water reaches the desired temperature, generally between 60ºC and 65ºC. This is necessarily high to kill off harmful bacteria in the water, but will scald if not mixed with cold water for washing – so be careful! In actual fact your tank only need be heated up this high for an hour each day, so you could set it to a lower temperature the rest of the time.
 
Time switches (from £50) allow you to heat the right amount of water at the right time – take advantage of off-peak electricity tariffs by setting the timer to heat water at a cheaper, off-peak rate.  Also, set your water to heat up only when you need it - keeping it constantly hot uses A LOT of energy. And make sure that your tank is well lagged/insulated in order to keep your hot water hot for longer – you may even have enough of the morning’s hot water left for the evening!
 
Boost switches (£25) activate a small secondary heating element at the top of the immersion cylinder, which is useful should you need a small amount of water at expensive peak times during the day. Since heat rises, the water in the tank will ‘stratify’ with the hot water remaining at the top and the cold below it (the hot water supply draws from the top of the tank).
 

‘Wet’ heating system controls

The right controls could slash your energy usage and save you hundreds of pounds a year, and upgrading or installing heating controls can be done without replacing your boiler.  This is particularly well worth doing if your current controls are over 12 years old - room thermostats for example are much more accurate these days.
 
Room thermostats (from £20) will control your boiler output depending on the temperature of the air – it is important that the thermostat is not covered or near a heat source. Your thermostat should be set to the lowest comfortable temperature - generally between 18°C and 21°C. Turn your thermostat down a degree or two until you reach a comfortable temperature for you.
 
Turning your thermostat up when it is colder outside is not necessary as the house will heat up to the set temperature whatever the weather – however if it is cold outside, it is likely to take longer to warm up inside so you might want to set your heating to come on earlier in cold months.
 
A programmable room thermostat combines time and temperature controls and allows you to set different temperatures for different times of the day. Room thermostats should be positioned thoughtfully – put in a cold place the rest of the house will be warmer than the temperature set, and the inverse is true if placed somewhere generally warm.
 
Thermostatic radiator valves (TRVs) (from £15) allow you to have different temperatures in individual rooms. TRVs are installed on each radiator and reduce the flow of water through their respective radiator when the temperature rises above the set amount.
 
Note: like room thermostats, TRVs work best uncovered, and it is best not to use radiator covers in conjunction with them.
 
Zone control (£1,000) saves you energy and money by separately heating different parts of your home that need different temperatures, so as not to overheat unused rooms, bedrooms, bathrooms, or kitchens, or underheat cold rooms. Each separate heating circuit has its own programmable room thermostat. Zones can also be set by using thermostatic radiator valves (TRVs).
  
A Boiler interlock (£installation) is a simple method of wiring your controls, so that your boiler turns off when neither the heating system nor the hot water needs it. Without it the boiler can continue to ‘cycle’, wasting energy.
 
Boiler thermostats (£integral) set the temperature of the water that will be pumped through your radiators. The higher the dial is set, the quicker and more effectively the system will heat your home – if not set high enough your home may never reach its desired temperature.
 
If you have a room thermostat and room controls you can set the boiler thermostat quite high, but this means that pipes and radiators could get very hot, so set it lower if there is anyone in the house whom this may affect.
 
Programmers or time controls (from £50) allow you to set ‘on’ and ‘off’ time periods and will automatically switch your heating off when you don’t need it, such as when you’re out or asleep in bed.
 
Most models will let you set the central heating and domestic hot water separately (not applicable for combi boilers) and will have manual overrides. Remember to change the time on it when the clocks change!
 
Your house and heating will have both a warm-up time and cool-down time. Ideally, you want the warm-up time to peak just when you need the house to be warm (when you get up say), and the cool-down time to begin before you retire for the day – you might need to play around a little with the settings to get your heating system running just right, and not wasting money and energy unnecessarily.
 
If you insulate your home, it will warm up more quickly and cool down more slowly, so you’ll save even more money on heating.
 
Set your water to heat up only when you need it - keeping it constantly hot uses A LOT of energy. And make sure that your tank is well lagged/insulated in order to keep your hot water hot for longer – you may even have enough of the morning’s hot water left for the evening!
 
Optimum start controllers (from £100) learn how quickly buildings reach the desired temperature using internal and external sensors, bringing the heating on at the optimum time prior to building occupancy. This results in the heating coming on later on mild days, potentially providing a 10% efficiency improvement.
 
Weather compensation controls (from £200) are very nifty devices that learn the lag between what the temperature outside does and what the temperature inside does, so they can instruct your boiler even more accurately when it needs to come on or turn off, or adjust the temperature required within the system. Weather compensation controls are easily installed and will pay for themselves in only a few years.
 

Storage heaters from £200; fuel 15p/kWh; CO2 0.6kg CO2e/kWh (if on Grid electricity)

If your home is heated by electric storage heaters, which utilise less expensive off-peak electricity to charge at night and release heat during the day, then the best way to ensure they run as efficiently as possible is to manage them properly.
 
Do this by setting the Output dial to the amount of heat you require now (it will only output if there is stored heat) and the Input dial to how much heat you think you will need tomorrow (it determines how much electricity will be taken from the grid overnight, and thus how much heat will be available the next day). 
 
Should a heater run out of heat when you still want some, or if the weather gets colder, you will need to turn the Input dial up a bit. If the weather gets warmer, or the heater doesn’t run out of heat in the evening, you can save money by turning the Input dial down a bit.
 
When you go out, turn the Output dial to low or zero so you’re not wasting energy heating empty rooms. You can also do this an hour before you go to bed as it will take time for the heater and room to cool down.
 
When you don’t need the heaters at all, turn them off at the wall and not just by turning the dials to zero – but remember to turn them on again the day before you need the heating again!
 
Modern storage heaters also have room thermostats that will control the output amount depending on the temperature of the air – it is important that the thermostat is not covered or near a heat source.
 
Your thermostat should be set to the lowest comfortable temperature - generally between 18°C and 21°C. Turn your thermostat down a degree or two until you reach a comfortable temperature.

To read more about modern fan-assisted storage heaters, look here.

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