How to Balance Radiators

Balancing radiators - A step by step guide

Without radiators, our homes would be very cold come winter time, especially in the UK. However, overtime, hot and cold spots can appear on radiators and some may even not get as hot as others throughout the home. If this happens to you, it's usually a good indication your radiators need balancing.

Central heating systems in the UK work by hot water being pumped around your home through a single pipe to all of the radiators throughout the house and looping back to the boiler again. By the time the hot water gets to the last radiator though, the heat and water pressure will have dropped throughout the system, providing the last radiator with the least hot water to heat up the air in the room. Radiator balancing helps counteract this by making small adjustments throughout the central heating system to ensure the whole system receives enough heat and water pressure to heat your rooms appropriately.

Read on for our comprehensive guide on all things radiator balancing and step by step instructions on how to balance radiators.

Balancing Radiator Lifestyle Image

What is radiator balancing?

Radiator balancing adjusts your radiator valves to ensure all the radiators in your home heat up at the same speed.

When do you need to balance your radiators?

You need to balance your radiators when you notice cold spots starting to appear in the radiators or your radiators are heating up at different rates. Unbalanced radiators lead to cold spots and rooms in your house which are very noticeable.

Should you balance or bleed your radiators?

While it is possible to bleed or balance radiators yourself, you should only attempt to do so if you are confident you can do it correctly. Otherwise you may risk accidental scalding yourself or simply not resolving your issue. Mobility issues and time constraints may also impact your desire or ability to complete this time-consuming job yourself. For safety and best results, it's better to ask a heating engineer to do it for you.

If individual radiators are showing cold spots in patches across the surface, you'll need to bleed your radiators first. Before bleeding your radiators, make sure they are turned off and are completely cool to avoid being scalded.

If some rooms are colder than others, it means some radiators are heating faster than others and so will need balancing as the water flow has been restricted. You will do a better job at balancing your radiators if you bleed them first as it will provide you with a more accurate temperature reading.

Tools you'll need to balance your radiators

  • Radiator bleed key
  • Lockshield valve key
  • Screwdriver
  • Digital thermometer/multimeter with thermometer
  • Adjustable spanner

How to balance radiators

Now you know a little more about radiator balancing, let us help you balance your own radiators with our fast, easy step by step guide.

Step 1 - Turn off your heating

The first step is to completely turn off your heating system and give your radiators the chance to cool down. Do not try to balance your radiators when they are hot as this can cause injury to you.

Step 2 - Open all of your radiator valves in your home

Most radiators will have two types of valve, either a lockshield valve, which usually has a push-on cap or a Thermostatic Radiator Valve (TRV). Whichever radiator valve you have, you now need to go around and open every valve on all the radiators in your home by turning them anti-clockwise. Thermostatic radiator valves can be turned quite easily by hand but a lockshield valve will need the adjustable spanner to open it.

Step 3 - Find the fastest heating radiator and make a note

Now all of your radiator valves are turned on, you need to turn your heating back on and make a note of the speed in which each of your radiators heat up. Usually you will find the radiators closest to the boiler will heat up the fastest as the water has less distance to travel but it is still important to make a note of these.

Step 4 - Turn your heating system off again

Once you have made a note of the speed of your radiators you then need to turn off your heating and let the whole system cool down again. It is best to let the system completely cool down before continuing the next steps so we suggest letting your heating system cool down overnight.

Step 5 - Turn the heating back on the next morning

If you've left your radiators to cool down overnight, you can now turn them back on the next morning and make your way to the radiator that heated up the fastest.

Step 6 - Adjust the fastest radiator to begin the balancing process

On the radiator that heated the fastest, close the lockshield valve completely before starting. Begin by opening the valve by one quarter of a turn to allow the radiator to heat up. Take measurements of the temperature with your digital thermometer or multimeter with thermometer.

Take a reading of the temperature of the pipework next to the valve, then take a temperature reading of the pipework on the opposite side of the radiator, usually where the TRV is. Make a note of both of these readings. Slowly and gradually turn the lockshield valve until the difference between the readings of the two pipes is exactly 12°c. This is a slow process and you will need to wait for the temperature of the radiator to change each time you adjust the lockshield before you can get an accurate measurement.

Step 7 - Repeat process for other radiators

Now that you have balanced your first radiator, it's time to go around all of the other radiators in your home and repeat the process. It's best to do this in the order the radiators heated up, from quickest to slowest. If you don't feel comfortable carrying this out yourself you can get in contact with a registered gas safe engineer to help you carry out this process.

Further help and advice

If you would like further advice on radiators, please check out our other expert guides below:

  • How to fit and replace a radiator
  • How to remove a radiator
  • How to change a radiator valve
  • What are the running costs of an electric heater?