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7 ways to prepare your boiler and heating for winter

Make sure your boiler and heating systems are on top form this winter

7 ways to prepare your boiler and heating for winter

Gas prices are up, putting pressure on all our pockets. The last thing we want is to fork out on expensive boiler repairs and unnecessary callouts.

While it’s always best to get a professional engineer for the big stuff, there are lots of small checks and repairs you can carry out yourself.

We’ve paired up with experts from the Heating and Hot Water Council (HHIC), and boiler manufacturer Ideal Heating, to bring you seven tips to ensure your boiler and radiators are working efficiently over the cold winter months.


If your boiler is old and inefficient, it may be time to get a new one. Head over to our roundup of Best Buy boilers


1. Set your heating to the right temperature

person changing temperature on their boiler control panel

If you haven’t already, turn your boiler on and increase your thermostat one degree at a time until your home reaches a comfortable temperature. The NHS recommends you heat your home to at least 18 degrees.

Turning up the heating incrementally will make sure that your home doesn’t get heated unnecessarily, saving you from wasting money and high amounts of energy.

If individual rooms feel too hot or cold, the HHIC recommends checking the temperature with a thermometer, and, if you have them fitted, you can then adjust the rooms thermostatic radiator valves accordingly.

Read our guide on boiler controls and thermostats to find out how they can save you money on your heating bills

2. Check for leaks

copper pipe with tear in it leaking water

You don’t want to wait to the depths of winter – just when you need your heating the most – to discover a leak that puts it out of action.

Run your heating for a few hours while the weather is still mild and check that everything is working properly and that there are no leaks.

  • Listen for ‘kettling’ Ideal Heating recommends you listen for out-of-the-ordinary sounds from your boiler such as ‘popping, whistling or banging’ noises: sounds that remind you of a kettle. It could mean there’s a build-up of grime inside the boiler, and you’ll need to callout an engineer to investigate.
  • Carbon Monoxide leaks You should install a CO alarm if you haven’t got one. Call an engineer immediately if you suspect a leak or experience the symptoms of carbon monoxide poisoning.
  • Gas leaks If you smell gas you should report it immediately. Call the 24 hour emergency number 0800 111 999 to report a suspected gas or carbon monoxide leak. You should also do this if a pipeline is struck (even if no gas leak has occurred).
  • Water leaks This is typically a sign of high pressure, loose joints or a leak from inside the boiler. Hot leaking water can be a burn hazard, as well as slip hazard, so, if you spot water leaking, call out an engineer.

3. Check your system pressure

person setting boiler controls

While it doesn’t necessarily damage your heating system, low boiler pressure can cause your radiators to not warm up efficiently, leading to inefficient heating and higher bills.

The most common reason for your gas boiler pressure being too low is either a water leak somewhere in the system or reduced system pressure as a result of bleeding a radiator.

This check is quick to carry out. Just locate the gauge on the front of your boiler. The indicator should normally be between 1.0 and 2.0 bar (often highlighted green) but check the recommended pressure in the manufacturer’s instructions.

If the gauge is below 1.0 bar (often coloured red) then the pressure needs increasing. If your boiler instructions say so, you can do this yourself by using the boiler’s filling loop, follow the manuals instructions. If you’re unsure, contact your boiler manufacturer’s technical department or a qualified heating engineer.

After this, you should find your radiators start heating up quicker. If you find, however, that the pressure drops immediately, or in a short space of time, it most likely means there’s a leak. In this case you should contact a qualified heating engineer, such as those vetted by Which? Trusted Traders to diagnose and fix the issue.

4. Check your radiators are heating up

woman with hand on radiator

The whole body of a radiator should get hot. If it doesn’t, then you won’t be heating your home efficiently, leading to you getting slapped with higher heating bills.

Where a radiator is cold, it is often a sign of an underlying issue:

  • Radiator is cold at the top The radiator likely needs bleeding
  • Radiator is cold at the bottom There is likely a build up of sludge and the heating system needs cleaning out by an engineer. When they do this they should add a central heating inhibitor – a chemical liquid that protects against sludge build up in the future.
  • A radiator is colder, or heating up slower, than others It is likely that your radiators need to be balanced.

How to bleed a radiator

bleeding a radiator rag under valve

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. All you will need is your radiators bleed key and a cloth or towel.

  1. Turn your heating off and let your radiators cool down.
  2. Locate the bleed valve on the radiator body. It is usually at the top and side of your radiator.
  3. Insert the bleed key, and slowly turn it anticlockwise until you hear a hissing sound – that’s the air leaving the radiator. Make sure your holding the cloth or towel underneath the valve to catch any water.
  4. Once the hissing stops and water starts to leak out of the valve turn the key clockwise to close it.
  5. Repeat on all the radiators you want to bleed, then turn your heating back on. Check that the cold spots have gone.

If you have a pressurised system, bleeding your radiators will likely drop the boiler pressure, so follow tip 3 to check it is still within 1.0 to 2.0 bars.

How to balance your radiator

picture showing effects of an unbalanced heating system

An unbalanced heating system means you’ll likely be using more energy (and money) than you need to be.

Luckily, it is easy to tell if your system is unbalanced, if your radiators aren’t evenly hot across the body, or some take much longer to heat up than others it is likely your system isn’t balanced.

If you still aren’t sure, read our guide on how to balance and bleed your radiators.

If they do need balancing, it is best to call out an engineer to carry this out. While this will cost some money, in most cases, the boiler can then be run at a lower temperature, increasing efficiency and saving you money on heating for several winters to come.


Concerned about climbing prices? Find out more about how to save money on your household bills


5. Insulate your condensate pipe

frozen pipe with icicles

A frozen condensate pipe can suddenly make your boiler stop working right when you need it to combat bitterly cold weather.

Prevention is better than a cure, if you have any condensate pipe that runs on the outside of your home, get it insulated. This will keep your boiler running throughout winter.

You can insulate a pipe yourself, but, if you’re not sure what you’re doing, you can call in a professional for an assessment. This will ensure the correct material is used for the insulation (it should have a waterproof and UV-resistant coating) and be installed to the latest regulations.

If it does freeze, read our guide on how to thaw your frozen condensate pipe.

6. Get your boiler serviced

boiler engineer servicing boiler

If you haven’t already this year, you should get your boiler serviced. This will significantly lower the chances of your boiler breaking – our 2021 boiler survey found that the chances of your boiler breaking in its first six years are doubled if you don’t get an annual service.

Read our advice on getting the best boiler service to find out how much you should be paying

Benchmark App

Remembering to get your boiler serviced can be a pain, but a new app from Benchmark (available on iOS and Android) will make boiler servicing more transparent and easier for homeowners to stay on top of.

Like a car’s service booklet, the Benchmark app acts as a digital record of your boiler’s installation and servicing history. If your boiler has been installed within the last 12 months, and a Digital Benchmark record created by your installer, it will let you see exactly what has been done during your boilers installation and each service.

The app sends push notifications to alert you when it’s time to get your boiler serviced.

This should make it easy to keep up with servicing your boiler, ensuring it remains in warranty and your heating system performs as efficiently as possible.

7. Diagnose potential issues

heating engineer with clipboard inspecting boiler

Sometimes, when your boiler doesn’t behave as you’d expect, it is worth doing a little bit of diagnostics yourself first before reaching to the phone to call your engineer.

Some issues are simple to solve, and, even if they don’t fix the issue, you can be safe in the knowledge that you’ve ruled these causes out

Boiler isn’t turning on

  1. Check the main power switch for the boiler is on. Sometimes this can accidentally get knocked.
  2. Check your thermostat is turned up enough to bring the heating on.
  3. Check the clock/timer settings, it might be that the boiler isn’t scheduled to be on at this time.
  4. If you have a smart thermostat, check the connectivity on your smartphone app to make sure the thermostat is communicating with the boiler.

Radiators are heating up when they aren’t meant to be

Set your boiler controls to ‘hot water only’. If the radiators are still heating up it is most likely that there is a faulty valve and you’ll need an engineer to come and fix it.

Boiler fault codes

Most modern boilers display fault codes in their display when something goes wrong. This will show as a letter ‘F’ followed by a number.

A visit from an engineer is likely to be needed to establish the cause if it persists, but you may be able to reset it in the interim.

Note down the fault number, and then follow your boilers instructions to reset the boiler.

When to call out an engineer

Boilers involve complex parts, gas, hot water and electricity. While we’ve outlined some steps you can take to prepare your boiler and heating for winter, you should always call out a Gas Safe registered heating engineer for:

  • Any repair inside the boiler – you shouldn’t be taking the casing off
  • Anything to do with the gas supply or gas meter itself
  • Changing the valves on a radiator – you can replace the plastic part of a TRV yourself, but anything else should be looked at by a professional
  • Recharging the heating cylinder
  • Anything that involves electricals.

In the event your boiler needs a repair, read our guide on common boiler problems and repair costs to make sure you’re not paying over the odds


Whose responsibility is it to fix a boiler in a rental property?

When it comes to boilers, it isn’t always clear what tenants are responsible for.

It is always best to check your own tenancy agreement, but, in general, tenants are expected to use their boiler and heating in the right way, and report any issues or faults to your landlord.

So make sure the heating is set to an appropriate temperature, check for leaks, check the system pressure and bleed the radiators if needed.

However, your landlord is responsible for:

  • Making sure the boiler is serviced annually
  • Repairs to the boiler and gas pipes

So, if you discover an issue with your boiler that would require calling out an engineer, contact your landlord straight away.

Check out our guide to tenants’ rights. Shelter also has more information on landlord and tenant responsibilities for repairs.


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