Radiators Cold at Bottom
Radiators that are hot at the top but cold at the bottom, reducing heat output.
What Is Causing This?
- 1Sludge and iron oxide build-up settling at the base
- 2System not flushed or treated with inhibitor
- 3Poor circulation due to a failing pump
How Urgent Is This?
This should be fixed in the coming weeks. Leaving it may allow the problem to worsen and cost more to repair.
What Needs to Be Done
A heating engineer will powerflush the system to clear sludge, add inhibitor, and check the pump is circulating properly. Individual radiators may need removing and flushing.
How Much Will It Cost?
National average estimate
Labour: £565 – £1,488 | Materials: £363 – £1,238
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Prices are estimates based on typical UK rates. Actual costs depend on the specific issue, accessibility, and your location. All quotes from tradespeople on Tradesfolk are completely free.
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Ask a QuestionHow to Prevent This
Add and maintain corrosion inhibitor in the system. Fit a magnetic filter to catch debris. Have a powerflush every 5 to 10 years.
Related Problems
One or more radiators stay cold or only warm up partially while others in the house work normally.
Banging, gurgling, ticking, or clicking sounds from radiators, pipes, or the boiler when the heating is running.
Water dripping from the connection between the radiator and the valve, often leaving a pool on the floor.
Other Heating Engineer Problems
Banging, gurgling, ticking, or clicking sounds from radiators, pipes, or the boiler when the heating is running.
The room thermostat does not respond, displays incorrectly, or the heating does not follow the set temperature.
Underfloor heating that has stopped producing heat or heats unevenly across the floor.
The house takes a very long time to reach the set temperature, with radiators warming up slowly.