Heating and hot water in an EPC upgrade

Why this page exists on a site about lighting

Because a page that tells you lighting is the answer to every building is not worth reading. In a warehouse with good plant and bad lighting, lighting is the answer. In a 1970s office with an ageing gas system, lighting is a sensible first move that will not get you to a B on its own, and being told otherwise wastes a year.

The honest version is that measures come in an order, the order depends on the building, and the cheap ones go first only up to the point where they run out of headroom.

What the cheap end of heating looks like

Not every heating measure is a plant replacement. Controls, zoning and time scheduling on an existing system sit much closer to lighting in cost, and in a building where the heating runs on a crude time clock they can be the easiest remaining win after the lights.

Zone controls and thermostatic control where there is currently none.
Time scheduling matched to actual occupancy rather than to a lease term.
Insulating distribution pipework and hot water storage, which is cheap and routinely skipped.
Decommissioning oversized or redundant hot water provision, common in buildings whose use has changed.

A commercial plant room with boilers, insulated pipework and valves. — Illustrative image generated with AI. Not a photograph of a building we have worked on.

The expensive end, and when it becomes unavoidable

Plant replacement — including electrification with heat pumps — is a different order of capital and a different order of disruption, and it usually needs a lease event or a planned refurbishment to make sense. It is also where the largest rating movements live.

If you are several bands short, the realistic plan is lighting and controls now, a proper assessment to confirm what is left, and plant tied to the next refurbishment or void period rather than done in a panic near a deadline.

Questions we get asked

Should I do heating before lighting?

Rarely. Lighting is cheaper, faster and less disruptive, so it almost always goes first. Heating comes into the plan when lighting and controls will not close the gap on their own, or when a refurbishment is happening anyway.

Will a heat pump improve my EPC rating?

It changes how the heating is modelled, and in many buildings that is a substantial improvement — but not in all of them, because the result depends on the fabric it is heating and what it replaced. This is a case for modelling your specific building before committing.

Can I get a rating improvement without touching heating at all?

Often yes, particularly in buildings where lighting is a large share of the load and the heating is already reasonable. Warehouses and distribution buildings are the clearest example.

Last updated 8 October 2026.