Sometimes heating seems to run endlessly without delivering extra comfort. Radiators are warm, the system stays on, yet the house never feels properly settled. This usually isn’t because the boiler is failing. It’s because the extra heat is being lost as fast as it’s produced.
When run times increase without a noticeable comfort gain, it’s rarely helpful to focus on controls alone. Heat loss is usually the limiting factor, which is why using the house cold diagnostic helps explain where the energy is going.
As heat loss rises, the heating system compensates by running longer. Walls, floors and roofs absorb heat continuously, and draughts move warm air away. The system keeps working, but the house can’t retain the added energy.
This creates the impression of weak heating. In reality, output hasn’t dropped. Demand has increased beyond what the building can comfortably hold.
A common response is turning the thermostat up further. While this raises output, it doesn’t change the underlying loss. The heating runs longer still, but comfort barely improves.
The least disruptive improvement is reducing how quickly heat escapes. Once loss is slowed, run times shorten naturally and warmth becomes more noticeable.
If heating runs much longer during cold or windy periods and settles again in milder weather, that pattern strongly points to exposure-driven loss.
In most homes, heating runs longer without feeling warmer because extra energy is being absorbed or lost rather than stored. Understanding that mechanism helps explain why longer run times don’t always mean better comfort. For broader guidance on improving efficiency without chasing settings, the guide on how to keep a UK home warm for cheap ties this behaviour together.
