This Practice Note summarises the obligations under the Heat Network (Metering and Billing) Regulations 2014, SI 2014/3120. The regulations affect landlords, management companies and developers who supply heating, hot water and air-conditioning to tenants in multi-let buildings. This Practice Note looks at who the obligations apply to, the buildings affected, the duties imposed, as well as providing information on replacing meters, renovations, maintenance obligations, billing and enforcement.