• 9 min read

Become a master of controls and save energy this winter! Some helpful advice from the Office of Public Works (OPW).

Reduce your costs by using heating controls

Using heating controls will help you reduce your costs by only using heat when you really need it. Follow the steps below, but if in any doubt, check your instruction manual or consult a registered professional.

  1. Set programmers and timers for only when you need heat
  2. Turn down your main thermostat by one degree - ideally to 19-20degrees in living areas
  3. Set radiator thermostats for the requirement for each individual room
  4. Check the temperature settings for your hot water
  5. Minimise immersion water heating
  6. Check the flow temperature settings on your boiler
  7. Turn off the hot tap 'pre-heat' function
  8. Keep an eye on your boiler pressure

Set programmers and timers only for when you need heat

Most experts agree that, in the long run, it’s best to have the heating on only when you need it rather than leaving it on all day. It's a given that a certain amount of energy is constantly leaking out of your home. How much will depend on how good your insulation is.

If you're keeping the heating on all day you're losing energy all day, so it's better to heat your home only when you need it. Use your programmer or timer to set the times when you need heat. Typically, if you time the heating to come on half an hour before you get up the home will be warm when you get out of bed.

If you are heading out for the day, time the heating to switch off at least half an hour before you leave, as the home will take time to cool down. The same heat-up and cool-down times apply when you return home and before you go to bed. Play around with the times to see what works best for your home.

Turn down your main thermostat by one degree

If you turn down your main thermostat just one degree it will cut your heating bills straight away, and you may not feel any difference. If your heating system has a main heating thermostat, or a programmer where you can set the temperature, then this is the most important part of your heating system to get to grips with. Try turning the temperature down by one degree. Wait for a day and see how it feels.

If you’re still feeling OK, turn it down another degree, and wait and see. And so on.

As soon as you start to feel a bit too cold, turn it back up by one degree. Make a note of the setting. This is the temperature setting for you and your household. Most families are happy with a setting somewhere between 18˚C and 21˚C but you may need it warmer if there are any elderly or infirm people living in the property.

The temperature will also depend on the nature and layout of your house and heating system, and on where the thermostat is, as well as on personal preference. Find the lowest temperature that you’re comfortable with. Then you can be sure you’re paying no more than you need to for a comfortable home.

Set radiator thermostats for the requirement for each individual room

Many of our homes have radiators with Thermostatic Radiator Valves (TRVs). They can be used to set the temperature of each individual room (other than where your main thermostat is). The key is find a setting, the ‘Sweet Spot’, and leave it there. When the temperature in that room rises above what's set on the radiator valve, it will stop water flowing through that particular radiator. The boiler will still be on to heat other rooms, but it will use less energy. If you're spending most of the day in one room you can use them to make sure you are not heating the whole house, just the room you are in.

The frost protection setting can be useful for rooms that are rarely used. Bedrooms can be put to a lower setting as most of us prefer it a bit cooler when we are sleeping. Somewhere between 16-18 degrees suits most for the bedroom. You may need to play around a little at the beginning until you find the sweet spot for yourself. If the room is not warm enough – turn it up a little (half a setting) and down a little if the room gets too hot. Allow one hour for the temperature to stabilise. Once you find this sweet spot you could place a green dot at the ideal setting.

This will make it easy to check the thermostatic radiator valve is at the ideal setting to maintain your desired room temperature. If you open a window to air a room, keep in mind that if the room cools the radiator will start to come on again and you could be cooling the room as fast as the radiator is heating it. In this case, do turn down the radiator before opening a window, but remember to turn it back to the sweet spot when you close the window.

Check the temperature settings for your hot water

If you have a hot water cylinder check that the temperature of the thermostat is set no higher than 60 degrees. Hot water cylinders need to be kept at 60 degrees, to avoid the dangers of legionella bacteria in water that is stored in the cylinder. However, having them set any higher is wasting energy and costing you more than needed.

If you have a combi boiler (in other words, you don't have a hot water cylinder), you will not be storing water and legionella bacteria are less of a concern. Therefore, you will easily be able to adjust the temperature of the water that comes out of your hot water taps. There is usually a tap symbol beside the controller. About 55 degrees should be enough for most.

Minimise immersion water heating

Firstly, it's generally much cheaper to heat water using your gas or even oil central heating system, rather than electricity with an immersion. Therefore, if you have a boiler it's likely to be cheaper than using an immersion heater every day, especially if you have the heating on anyway at the same time.

However, an immersion heater can be your primary water heating, for example if your home has electric heating. Many homes also have them as a back-up water heater for a central heating system. This means that if your boiler fails, you still have a way to heat your water. It is best to use a timer to turn the immersion heater on and off so hot water is ready at times when you need it.

Alternatively, a boost button can be very useful to make sure it is not left on any longer than required. If you have a time-of-use tariff, or night saver tariff, set your immersion heater to switch on when electricity is cheaper.

It’s best not to leave your immersion heater running all the time. No matter how well-insulated the immersion tank is, it will still lose heat and the drop in water temperature will cause the immersion heater to run repeatedly, like your kettle coming back to the boil over and over again.

Check the flow temperature settings on your boiler

Most modern boilers have a dial or digital display that allows you to set the temperature of the water that leaves the boiler to heat the radiators in the house. If you lower the temperature, your boiler will operate as efficiently as possible. If you increase the temperature, you will heat your radiators more quickly but your boiler’s efficiency could decrease by around 10 or 20 per cent.

Please note, this is different from turning down your main heating thermostat or the valves on your radiators. Changing the flow temperature won't lower the temperature of your home. Your radiators will just feel slightly cooler. For homes with modern double glazing and good insulation, dropping your flow temperature will have no impact on comfort. Even those in older homes that have been modernised and draught-proofed can do this. Some in older homes may need to set it higher, but for most, it's a simple way to save.

If you have a condensing combi boiler you should set it to about 50 degrees to maximise your boiler's efficiency. You can set this with the control that usually has a radiator symbol next to it. If you set the temperature too high, the boiler won't be able to operate in condensing mode, so you're wasting energy. If you have a boiler and a hot water cylinder, there are still adjustments you can make to improve your system's efficiency, though the temperatures generally need to be set a little higher than with a combi.

Most condensing boilers are set up to supply one temperature for heating and hot water, in which case you should have it set to 70 degrees to be safe. Hot water cylinders need to be kept at 60 degrees – to avoid the dangers of legionella bacteria in water that is stored in the cylinder – so the boiler has to supply a higher temperature to allow for any heat losses as the water makes its way to the cylinder.

Turn off the hot tap 'pre-heat' function

Most modern combi boilers and some other systems have a 'pre-heat' function, so the hot water in your pipes is set at a certain temperature, to ensure you don't have to wait too long for your water to heat up.

However, while pre-heating is more convenient and less water is wasted, it is hugely inefficient from an energy saving perspective, particularly in homes where the occupants are out at work all day. Check the boiler manual for instructions on how to turn the pre-heat off.

Keep an eye on your boiler pressure

It's also worth checking the pressure gauge on your boiler regularly. This tells you the pressure of the water circulating in the heating system. If it's too slow, it'll make your system inefficient, using more energy to heat your home to the required temperature.

The exact recommended pressure level will vary depending on the boiler manufacturer, but generally, anywhere between 1.0 and 2.0 bar is ideal.

On most newer boilers, the pressure gauge will be on the front of your boiler or under the control panel. On older boilers, it may be harder to find. Check your boiler manual if you can't find it and for help with increasing the pressure.

SEAI's Home Energy Plan

We will send you regular emails with advice for home heating, electricity and appliances, and travelling. You can implement the advice at your own pace, learning how to break the bad habits we all have, save significant amounts of energy along the way, and reduce your energy bills.

OPW | Office of Public Works - Irish Government Agency

Created by the OPW for the Optimising Power @ Work programme