Radiator Cold at the Top? Here’s How to Bleed It in Under 5 Minutes
If your radiators feel warm at the bottom but cold at the top, they probably have air trapped inside — and bleeding them is a quick, simple fix.
In this blog post, we’ll show you exactly how to bleed your radiators safely and restore full heat to your home.
Why Bleed a Radiator?
Air can build up in your heating system over time. When that happens, hot water can’t circulate properly, leaving you with cold spots — especially at the top of your radiator.
What You’ll Need:
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Radiator key (available at most DIY stores)
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Cloth or small bowl to catch any drips
Step-by-Step Guide:
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Turn off the heating and let the system cool down.
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Use your radiator key to open the bleed valve at the top corner of the radiator.
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Hold the cloth underneath and turn the key slowly.
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You’ll hear a hissing sound — that’s the air escaping.
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When water starts to come out, close the valve tightly.
Important: After bleeding one or more radiators, check your boiler pressure. You may need to top it back up — check out our blog on how to do that here.
Want to see the process in action? Watch our video: “How to Bleed a Radiator — Stop Cold Spots.”