How to Balance a Radiator

Balancing your radiator is vital if you want the heat to be distributed evenly throughout your home, keeping all spaces warm and cosy. While this process takes a bit of trial and error, it can make a huge difference in how much you use and spend on heating your property.

We’ve put together a step-by-step guide to how to balance a radiator, so you are left feeling confident and prepared for a successful outcome.

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To balance a radiator, you’ll need to turn off your heating and open all valves on the radiator. Then, turn the heating back on, and monitor which radiators heat up first to last. Once recorded, switch the heating back off. Once cooled down again, switch it back on and turn the lockshield valve off and then turn it a quarter to a half turn back. Measure the temperature of the pipes under the valves on both sides until each set reaches 12°C. Going in the order they heated up, all radiators should now be evenly warm.
There are several valves involved when balancing a radiator, including a lockshield valve, a thermostatic radiator valve, a manual balancing valve and an automatic balancing valve.
There are several challenges you may face when balancing a radiator, including not bleeding the radiator first, sludge or debris build-up, incorrect starting state, improper valve adjustment and pipework or pump issues.

Why do you need to balance your radiators?

As all your radiators are connected to one system, the ones installed closest to the boiler will often take most of the heat, not leaving much water to heat the ones further away. Additionally, as heat rises, radiators placed upstairs will take more than their fair share of the heat too, so you may find that the downstairs units furthest from the boiler never get particularly hot.

So, by balancing your radiators, you’re adjusting each one to make sure they all attain as much heat as each other, and needed to perform optimally, keeping your whole home cosy in the winter.

What's the difference between balancing and bleeding a radiator?

Balancing a radiator ensures their heat is distributed evenly throughout the home by ensuring every radiator creates the same amount of heat because naturally, the radiators closest to the boiler gain more. On the other hand, bleeding a radiator is the process of removing any trapped air from a radiator so that the entire surface heats up and efficiently warms the space.

Before you begin

Before balancing, it’s a good idea to bleed your radiators as this will give you more accurate temperature readings when you start balancing them.

What tools are needed to balance a radiator?

Radiator bleeding key
Adjustable spanner
Screwdriver
Digital thermometer

Time to balance your radiator

Follow the simple steps below to ensure you successfully balance each and every one of your radiators.

To begin, you’ll need to turn your heating off and wait until it completely cools down. Then, open the valves on all of your radiators; some lockshield valves may require a spanner to loosen. This is typically located on the opposite side of the radiator to the main valve used to switch your radiator on and off.

Switch your heating back on and then pay attention to the order in which your radiators heat up. Usually, the first will be closest to the boiler, and the last will be furthest away. This will tell the story of how the heat flows through your system, so you know which order to balance them in.

When you’ve made a note of this, turn the heating back off and wait for the radiators to cool down again so that your readings will be accurate when balancing.

After every radiator has completely cooled down, switch your heating back on (again) and keep all the valves open. To distribute the flow to the next radiator rather than back to the boiler, turn the lockshield valve completely off starting with the first radiator, then turn it approximately a quarter or half turn back. The radiator will then start to heat up again.

You’ll want to measure the temperature of the pipework under the valves on both sides and adjust the lockshield valve until the difference between the two pipes reaches 12°C. Then you can move on to the next one in the system.

As you move from radiator to radiator, you should go in the order in which they heat up. You may find that the lockshield valve will need to be more open each time to allow more water to flow through.

If you’ve carried out this process properly, you’ll find that all of your radiators should now heat up evenly, from the closest to your boiler to the furthest.

How to balance a radiator with TRVs

Open all TRVs: Make sure TRVs are fully open by turning the dials anti-clockwise or removing the heads. Open the lockshield valves at the same time.
Turn on the heating: Keep an eye on this so you can monitor which radiator heats up first (usually the one closest to the boiler).
Turn the heating off & let it cool: Once cooled, slightly close the lockshield on the radiator that was fastest to heat up and reopen a ¼ of a turn. Do the same for each radiator in the order of the quickest to heat up to the slowest. Keep TRVs open the entire time.
Once balanced: Reset TRVs to a temperature you’re happy with.

Best practices for balancing a radiator in an old house

Bleeding radiators in old homes works the same as in new-builds, except you must check if there are any hidden system issues prior. A professional can help you do this.

Radiator balancing valves explained

Lockshield Valve: Found on the side of a radiator, and often hidden under a plastic cap. It’s manually adjusted with a wrench to restrict or allow water to flow through.

Thermostatic Radiator Valve (TRV): Installed in the inlet, these work to regulate each room’s temperature based on your settings. They’re not used for directly balancing flows like the lockshield.

Manual Balancing Valves: These are pre-built into some systems and are preset to provide a fixed flow resistance which equalises the pressure across the entire system.

Automatic (Pressure-Independent) Balancing Valves: These are a more advanced balancing valve that automatically adjusts to maintain constant flow, even if pressures change.

Compare balancing methods for different radiator types

You’ll need to adjust your balancing process according to the radiator you’re dealing with.

Panel rads: These are some of the quickest to balance as they heat fast, but you’ll need to make lockshield adjustments. This involves fully opening the valves, turning the heating on and then gradually closing the lockshields on the radiators that heat up the fastest, ensuring even heating.

Column/cast iron: These hold a lot more water than standard radiators, meaning they’ll warm slower and need larger flow allowances. You’ll need to restrain flow less and allow more time for heat adjustments.

Vertical/tubular radiators: Vertical radiators tend to have internal diverters, and if warm at the bottom but not top, you may need to invest in a flow diverter kit. Follow the same procedure but they may take longer to heat up completely.

What’s some challenges you may face when balancing your radiator?

Here are some common challenges you may face when balancing a central heating radiator:

Challenge: Forgetting to bleed the radiator first

Resolution: Always ensure you carry out this step prior to balancing a radiator as air trapped inside can stop the water from flowing evenly.

Challenge: Sludge or debris build-up

Resolution: Blockages live these can prevent your radiator from heating up evenly, leading to the bottom staying cold. You or a professional should flush the radiator first.

Challenge: Incorrect starting state

Resolution: This happens when you begin adjusting the radiators when they’re cold or when the valves are mis-set. Make sure you follow our clear instructions to prevent this.

Challenge: Improper valve adjustment

Resolution: Be careful when tightening or making any minor adjustments to the lockshield valves, as you’ll not be able to balance the radiator.

Challenge: Pipework and pump issues

Resolution: If your pipes are of an incorrect size or the pump isn’t powerful enough, it can prevent distant radiators from heating up. Consult a professional if this could be the case and they can replace any parts necessary.

FAQs

You don’t necessarily need a thermometer to balance radiators. As long as you feel they’re even in heat levels, you can follow the same process without hitting a certain temperature.

There’s only one solution to balancing your radiators properly which we’ve outlined in this article. This process can be fast and effective once you get the hang of it.

Balancing radiators tends to take about 2 hours for a standard home, but this’ll vary depending on how many radiators you have and the size of your home.

You’ll follow the same process as above, and map out which radiators are closest to the boiler and work in that order.

If your radiator is still cold after you’ve balanced it, you could be facing an issue of trapped air (it needs to be bled again), a faulty valve or a blockage. Always ensure you take the preventative steps for these which are found in the challenge section above.

We hope you feel confident in radiator heat balancing from our guide. All it takes is a few quick steps to even heat distribution throughout the home. If you enjoyed this read, check out our guide on how to replace a radiator.

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