Heat network zoning, explained

Zoning is a way of deciding, area by area, where shared heat networks should be built, and then making sure the buildings that would benefit most actually connect.

Heat networks are cheapest when many buildings join, but buildings will only join a network that already exists. Zoning is England's attempt to break that loop. Denmark broke it more than 40 years ago.

Designation is the moment a heat network zone becomes real in law. Getting there involves national mapping, local refinement, a coordination body and, after designation, a competition to choose the developer.

Zoning is shared between a national authority, local coordination bodies and private developers, with Ofgem and consumer bodies regulating the networks that result. Here is who does what.

Most households will notice nothing from heat network zoning for years. People in blocks with shared heating are the ones most likely to see a change, and they already have new consumer protections.

Zoning and planning are separate systems, but they meet at one point. For new buildings, the date of planning permission decides whether the building falls inside the zoning rules.

Public money pays for studies, early design and part of the build. Most of the cost of a zone is expected to come from private investors, who would be repaid by selling heat over decades.

England, Scotland and Wales have taken different routes. Scotland legislated first. England has the powers but not yet the regulations. Wales has neither. Ofgem regulation applies to all three.