If your radiator is cold at the top but hot at the bottom, trapped air is usually the culprit. Our replacement radiator air vents (also known as bleed valves) allow you to release this air quickly and easily, restoring your system to full efficiency. Over time, old vents can get painted over or seized, so swapping them out is a cheap and effective maintenance task.

We stock standard sizes to fit almost any UK radiator. Shop our collection of cheap radiator air vents below to find a simple, low-cost solution that ensures your home stays warm and your boiler doesn’t have to work harder than it needs to.

Filter

Tails the Retail Raccoon mascot

TAILS THE RETAIL RACCOON SAYS

Buying Radiator Air Vents: Quick Tip

If a radiator is cold at the top or makes bubbling noises, trapped air is usually the culprit. A correct air vent makes bleeding simple and helps the radiator heat evenly again. Before you buy, match the vent thread size and type to your radiator so it seals properly. If the radiator sits in a tight spot, choose a vent that is easier to access with a bleed key.

Who Should Buy Radiator Air Vents?

And who should consider alternatives

✔
Who Should Buy

People replacing a leaking or damaged bleed vent

Ideal if your current vent weeps, drips, or no longer closes properly after bleeding.

Homes with radiators that heat unevenly

Great if the radiator is regularly cold at the top and you want to restore even heat distribution.

Installations where access and maintenance need to be easier

Perfect if the radiator is in a tight position and you want a vent that is easier to reach and operate.

✘
Who Shouldn't Buy

People trying to fix a radiator that is cold everywhere

If the whole radiator is cold, the issue may be valves, balancing, or system circulation rather than trapped air.

Anyone unsure about the radiator vent thread size

Buying the wrong size can lead to leaks. If you are not sure, check the radiator instructions or match the existing vent.

Homes where air keeps returning frequently

If radiators need bleeding all the time, it may point to a system issue that needs attention, not just a new vent.

FAQs About Radiator Air Vents

Help with trapped air symptoms, vent selection and getting radiators heating evenly

  • What are radiator air vents and what do they do?

    Radiator air vents are fittings that allow trapped air to escape from a radiator so hot water can circulate properly. When air builds up, radiators can feel cold at the top, heat unevenly, or make gurgling noises. By releasing air, vents help the radiator warm up more evenly and keep the heating system running more smoothly.

  • How do I know if my radiator needs an air vent or bleeding?

    Common signs include the radiator being warm at the bottom but cooler at the top, inconsistent heating across the surface, or noises such as bubbling or sloshing when the heating is on. If you regularly have to bleed radiators, it can also suggest air is getting into the system, so it is worth checking for low pressure, recent plumbing work, or a maintenance issue that is introducing air.

  • What should I check before buying a radiator air vent?

    Check the vent type and the thread size to make sure it fits your radiator. Some radiators use specific bleed vent styles, and different radiator brands can use different connection sizes. Also consider access, if the vent sits close to a wall or within a tight recess, you may need a vent style that is easier to reach with a key. If you are replacing an existing vent, matching the old size and style helps avoid leaks.