For support call: 0330 100 3143
Find an Installer

Getting ready for winter - Why are my radiators cold?

We all know the feeling. We flick the heating on as we walk in the door (or if we’re a techy before we leave work using our phone), but it doesn’t seem to get as warm as it used to. Same temperature, same settings, different warmth. What’s going on? The issue may be in your radiators and the solution may surprise you with how easy it is. You might need to bleed your radiators.

Why bleed your radiators?

If your radiators aren’t heating up, are heating up unevenly or you can hear a bubbling or clunking noise – this might be because of air that’s trapped inside. But don’t fret! Radiators can be bled to release the trapped air, and it’s surprisingly easy to do yourself. We’ve made a handy guide that you can find here.

What's the impact of air in the system?

If your radiators are full of air, it can prevent the hot water reaching all the space inside. You could have your heating on full blast, but if it’s not spreading evenly through your radiators, you are just wasting energy (and money!).

When should you bleed a radiator and what do you need?

One of the first signs that you should bleed your radiators is when you have put your heating on and your home is still cold or if you hear a bubbling sound when you turn your heating on. If this happens, feel your radiators – you may notice that the radiators are hot at the bottom, but cold at the top.

In order to bleed your radiators, you need a radiator key so you can open the valves on your radiators – you’ll be able to buy one of these from most hardware stores, often for less than £1. Some valves may only need a flat head screwdriver, so double check the shape of the valve before starting. You will need a bucket or bowl to collect any water and a cloth can be handy to clean up. Sometimes the water that comes out of an old radiator can be discoloured, so a cloth will help save any light-coloured carpets!

How to bleed a radiator

Once you have got everything that you need, you can begin the process of bleeding your radiators.

How long will it take and how often should they be done?

How long it takes to bleed your radiators depends on the number of radiators and the amount of air in them – but it’s estimated that it should take 30 seconds to a minute for each radiator. For each radiator that you bleed, you should wait until water starts to come out of the radiator before closing the valve back up. This means that the water has risen to the top of your radiators as the trapped air has been released. You should check every radiator in your property to see if they also need balancing before switching your heating back on. Speak to your installer or find one here.

It’s recommended to only bleed your radiators if they are cold in certain areas when the heating is on. There’s no need to do it on a regular basis as you could open the valve to just release water which could get on your walls and floor.

Click here to go back