Older homes often develop uneven heating, where some radiators run scorching hot at the top while others feel lukewarm or cold at the bottom. These temperature differences can lead to higher heating bills and uncomfortable rooms, particularly in properties around Bordon, Whitehill, Liphook, Alton and Farnham. The good news is that many of these issues can be resolved with simple DIY steps.
Quick checks you can do now
- Feel your radiators from top to bottom to identify hot or cold areas.
- Ensure all radiator valves are open and not stuck.
- Check your boiler pressure is within the green zone (usually 1–1.5 bar).
- Listen for gurgling or trickling sounds, which can indicate trapped air.
Understanding radiator hot spots cold zones
This problem usually comes down to one of two causes: trapped air in the system or radiators receiving uneven water flow. Hot water should circulate evenly, but older pipework and sludge build-up can make some radiators work harder than others, especially in extended systems common in GU35, GU34 and GU9 homes.
Why trapped air causes uneven heating
Air rises to the top of a radiator, preventing hot water from filling the upper section. This leaves the top cold while the bottom remains warm. Bleeding removes this trapped air and restores full circulation.
How to bleed a radiator step by step
Bleeding radiators is a quick and safe job for most homeowners. Here is the correct method:
- Turn your heating on and allow radiators to heat fully.
- Locate the bleed valve at the top corner of each radiator.
- Place a cloth or tub underneath to catch drips.
- Insert a radiator key and turn it slowly anti-clockwise.
- Listen for the hissing sound of escaping air.
- Once water appears in a steady stream, close the valve.
- Check boiler pressure afterwards and top up if needed.
How radiator balancing improves heat distribution
Balancing ensures each radiator gets the right volume of hot water. Without balancing, the first radiators on the circuit (often closest to the boiler) may run extremely hot, while those further away remain lukewarm. This is common in older homes across Bordon and surrounding towns where systems have been extended over time.
Step-by-step radiator balancing guide
Balancing takes a little longer than bleeding, but the results are worth it. Follow this method carefully:
- Turn off heating and allow radiators to cool.
- Open both valves on every radiator fully.
- Turn the heating back on and note how quickly each radiator heats up.
- The fastest-heating radiator is your reference point.
- For this radiator, partially close the lockshield valve (usually with a spanner).
- Move to each radiator in turn, reducing flow by making small adjustments.
- The goal is to make all radiators heat evenly, not necessarily equally fast.
Checklist: things to watch while balancing
- Make only small adjustments – quarter turns are often enough.
- Always adjust the lockshield valve, not the thermostatic valve.
- Allow time between adjustments so temperatures can stabilise.
- If a radiator stays cold even after balancing, it may need flushing.
When DIY fixes aren’t enough
If radiators remain inconsistent after bleeding and balancing, the issue may be deeper within the system. Sludge, failing valves, pump issues or poorly designed pipework can all contribute. Homes around Bordon and nearby areas often have mixed-age heating systems where modern radiators meet older pipework, making professional assessment worthwhile.
Next steps: If you’d like a Gas Safe engineer to diagnose uneven heating or fully balance your system, contact us at (01420) 558993.