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Six heating and boiler tips for cold winter weather

Find out how to help protect your boiler and ensure your heating is efficient to keep you cosy through the winter weather

Six heating and boiler tips for cold winter weather

With February 2021 bringing wintery, snowy weather to large parts of the UK, none of us want the heating to pack in now.

We have six tips to help keep your boiler and heating working efficiently, ensure you stay toasty and warm throughout the cold winter weather – and may even save a little bit of money along the way.


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1. Defrost your boiler’s condensate pipe

If your boiler suddenly stops working when the weather turns bitter, then check to see if its condensate pipe has frozen.

If this pipe gets blocked with ice, then the condensation water that your boiler creates has nowhere to drain and your boiler will automatically shut down as a safety measure.

In cold weather, a frozen condensate pipe is one of the most common reported faults that stops a boiler working, but you can defrost the pipe yourself, without having to call out an expensive heating engineer to do it for you.

Step-by-step guide to defrosting your condensate pipe

  1. Locate the pipe: it will be a white pipe that comes out of the wall behind your boiler and runs directly to an outside drain.
  2. Boil the kettle: leave it to cool for 10-15 minutes afterwards, so that it’s warm rather than boiling.
  3. Pour the warm water over the pipe: start from the top of the pipe and work down until the ice has melted.
  4. Reset your boiler: it should now work normally.

Can’t reach your condensate pipe?

If your boiler is in the loft or you’re in a high-story flat, the condensate pipe may be out of easy reach. However, there is an easy temporary fix, as our principle sub editor can attest to:

‘I’ve just had my condensate pipe freeze over, but it’s up on the second floor of my house – so I thought I was going to have to go up a ladder to fix it.

‘However, when I rang my boiler engineer they gave me a really easy temporary fix, just to disconnect the pipe at the base of the boiler and catch the water in a bucket.

‘I have to empty it twice a day, but beats going up a ladder in the snow with hot water. I just have to wait until the weather warms up, and then reconnect it.’

Angus Dawson, Which? principal sub editor


Prevention is better than a cure: read our top tips for insulating your boiler condensate pipe to stop it freezing over in the future.


Person sitting against radiator

2. Bleed your radiators

Not only will it keep your central heating system in top form, bleeding your radiators might also knock a little bit of money off your heating bills.

Trapped air bubbles in a radiator will rise to the top of a radiator. Over time this can stop your radiators from heating up efficiently.

Fortunately it’s easy to diagnose and fix yourself.

Step-by-step guide to bleeding your radiators

  1. Turn the heating on full: wait for your radiators to reach their maximum heat.
  2. Check for cold spots: run your hand along the top of each radiator. If you feel any cold areas that’s a signal that radiator needs bleeding.hand on radiator
  3. Turn the heating off: let your radiators cool down so the hot water doesn’t burn you when you start to bleed your radiators.
  4. Locate the bleed valve: start with the ground floor radiator furthest from the boiler, you can find the bleed valve usually located at the top and side of your radiator.
  5. Place a towel under the bleed valve: use this, or a tray or container to collect any water that drips out of the valve.bleeding key inserted into radiator
  6. Insert your radiator bleed key: also hold a cloth or towel under the little drain hole to catch any water.
  7. Open the valve: turning it slowly, anticlockwise. You should hear a hissing sound as the air leaves the valve. Only open it a maximum of half-a-twist, to make sure water doesn’t escape the valve too quickly.bleeding a radiator rag under valve
  8. Close the valve: once the hissing stops and water starts to leak out you’ve got all the trapped air out so turn the key clockwise to close it.
  9. Repeat for your other radiators
  10. Check your boiler pressure: if you’ve bled a lot of radiators, the system pressure may have dropped. Check tip number 3 below, if you’re not sure how to do this.
  11. Switch your heating back on: give your radiators time to heat up and check that the cold areas have gone.

There are lots of other ways to reduce your heating bills – keep reading to find out another one.


person setting boiler controls

3. Check your boiler pressure

Low boiler pressure can cause your radiators to not heat up as they should, leading to inefficient heating and higher bills.

It’s quick to check what’s happening with the pressure of your boiler – just locate the gauge on the front of your boiler. Most will have a section on the gauge (1.0 – 1.5 bar) highlighted green. If the indicator is in this region your boiler’s at optimal pressure.

If the gauge is below 1.0 bar (usually coloured red) then the pressure needs increasing, and you can do this by using your boiler’s filling in loop.

Follow your boilers operating manual to find out how to re-pressurise your boiler model. After this your radiators should start heating up better.

If the problem persists, or the pressure keeps dropping, this may indicate a leak in your plumbing. In this case you should contact a qualified heating engineer (like those on Which? Trusted Traders) to diagnose and fix the issue.


Persistent boiler problems? Look out for these five signs you need a new boiler.


diagram showing sludge build-up in radiator

4. Clean out your radiator system

If you have cold spots near the bottom of your radiators, this could be a sign that sludge has built-up in your heating system. If particularly sludgy, it could even be increasing your heating bill by as much as 25%!*

Making sure your system water (the water that lives in your pipes and radiators) is sludge free will mean your heating system is more efficient.

If you suspect the radiators need a good flushing out there are a few different options available: read our power flush guide to find out more.

*independent research carried out by Enertek International.


Want to heat your home more efficiently? Our boiler control and thermostats guide will help you get control of your heating bills.


5. Check your boiler in the summer

This tip may seem counter-intuitive, after all who wants a blazing radiator in the middle of July!

But if you turn your heating off, and only turn it on when your house starts to get cold, you’ll likely only discover any issues with your boiler right at the time when you really want it to work.

By turning it on low for 15-20 minutes every so often in the summer, you can spot any problems and have plenty of time to get them fixed.

This way come next winter, you’ll have reduced the chances of any nasty surprises cropping up.


boiler engineer servicing boiler

6. Get your boiler serviced annually

To keep your boiler in top health, and help lower the chances of your boiler breaking when you need it the most, we recommend you get it serviced every 12 months.

7,500 boiler owners responded to our 2020 boiler reliability survey. We asked owners if they have ever needed a repair carried out on their boiler, and how often they had their boiler serviced.

As you can see, around two thirds of boilers that are serviced every year never need a repair.

This number drops dramatically as you increase the time between services, so spending a bit on a boiler service could potentially spare you a huge payout on a big boiler repair in the future.

A regular service from a registered heat engineer will ensure small issues are found and fixed before they become a big problem, and you can find out how to get the best from your boiler service in our advice guide.

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