Heating the home can be tricky as the weather heads closer to single figures, especially if your radiators are not doing their job properly.

The most frequent problems households have with their radiators are cold spots either at the bottom or the top. These areas remain cool when an obstruction hampers the water's circulation within the device, meaning that certain sections fail to heat up.

Matthew Jenkins, energy specialist at myjobquote.co.uk, offers a silver lining by sharing an “easy fix” for UK residents to remedy this without reaching deep into their pockets for professional repairs.

He said: “There can be multiple reasons why a radiator could be lacking heat at the bottom, however, the most common reason for a cold-bottomed radiator is a build of sludge and debris. Due to radiators being a constant damp environment, over the years we often see a buildup of debris which is an accumulation of dirt and rust.”

Explaining further complications, he noted: “Over time, this accumulation can begin to restrict and block the flow of hot water, causing parts of the radiator to lack the ability to heat. Due to a blockage, water is redirected to other parts of the radiator, meaning the bottom may not be reached by the flow of hot water.”

Households struggling with inefficient radiators can easily tackle the problem by using a chemical cleaner, according to expert advice from Matthew. To take on the sludgy challenge, Matthew recommends buying a central heating system cleaner from a local hardware store and following the instructions on the bottle for the quantity needed for the radiator system.

Elaborating on the solution, he said: “Let your heaters run for around an hour, before flushing it out and replacing the water. Flushing your radiator out will involve removing your radiator from the wall, so if you are not comfortable doing this yourself, always call a professional to carry out the task.”

Generally, the process should take about an hour with a chemical cleaner, Matthew notes. But for those facing a substantial build-up of sludge, they might consider leaving the cleaning agent in the radiator system for up to a week before flushing.

This extended period allows the chemical to dissolve all the accumulated grime thoroughly. The energy expert highlighted the importance of finishing the job correctly, saying: “Always remember to flush the radiator and replace the water after a chemical clean to ensure your radiator is safe for use in your home.”

For the eco-conscious individuals who prefer avoiding chemicals, Matthew advises that there is also the option to detach the radiator and clean it manually. In such cases, he instructed: “In preparation for cleaning your radiator you should first isolate your radiator by closing the lockshield valve to avoid any excess water leakage.

“Make sure your central heating system is switched off and the water inside has been left to fully cool. Allowing the interior water to cool completely before cleaning will avoid any serious injury.

“To close the lockshield valve, it may be necessary to use a spanner. If you have a thermostatic radiator valve (TRV), turn this down to zero. If your radiator does not have this function, you will need to turn a second valve on the opposite end with a spanner.

“Next you'll need to empty the water inside your radiator, so prepare your surroundings in case of spillage. Ensure your flooring is waterproof, and if not, lay down towels and keep buckets handy. Use a bleed key to open the valve at the top of the radiator. This will allow airflow to move through the system, and water will begin to pour from loosened valves.

“Once water has stopped pouring from the valves, it is advised to disconnect the radiator from the wall and pour the remainder of the water out.

"It's important to not fully undo any valves while disconnecting the radiator, as this can cause water to flow from your central heating system which may flood your home,” warned the pro.

Use a hose to give the radiator a quick blast, which should shake and remove any remnants and debris from the interior pipes. 

Ensure the water runs clean, and then reattach the radiator to the wall, attaching the fixtures and turning all valves back to their original positions.

Once the water starts to circulate again, households should close the bleed valve and test their central heating system to ensure it’s working properly.