Will your home's electricity supply need upgrading for a heat pump?

What to know first

These points explain the electrical checks that can affect an air source heat pump installation and its price.

A heat pump adds a significant electrical load, but many properties will not need a new supply. The answer depends on the selected model, the home’s other electrical loads and the capacity and condition of its existing connection.

The result may be no network work, a larger fuse, internal electrical changes, a replacement service cable or a three-phase connection. These are different jobs and may be carried out by different organisations.

Will the electricity supply actually need upgrading?

Not necessarily. The installer and electrician compare the proposed heat pump’s maximum electrical input with the capacity and expected demand of the whole property.

Heating capacity and electrical input are not interchangeable. The electrical assessment uses the model’s operating voltage, supply phase and maximum current or power input. It must also include relevant backup heaters and hot-water immersion heaters.

The Microgeneration Certification Scheme (MCS) design standard dated 5 December 2025 states:

It also requires advance permission where necessary.

The five checks that decide the answer

This table is a starting point. The property assessment and local network operator determine the final outcome.

As checked on 10 August 2026, new and amended electrical installations should conform to BS 7671:2018+A4:2026, the current UK Wiring Regulations. Amendment 4 took effect on 15 April 2026.

Expert insight

“Do not use heating capacity as a shortcut for electrical demand. Ask for the maximum electrical input in amps or kilowatts, including every auxiliary heater.”

Giles Crosse

Energy Editor

Experienced editor, journalist and communications consultant specialising in consumer energy and low carbon technologies.

• Editor and campaign author for Shell, EDF Energy and Good Energy.
• Consultant to the United Nations and contributor to the World Economic Forum.
• Journalist for Reuters, the BBC, The Economist and The Guardian.

More about Giles Crosse

Monitoring the property’s actual use can support the maximum-demand calculation. A load-limiting system may also be considered in some cases, but it must be fail-safe and compatible with the heating design. It is not a general workaround for an inadequate supply.

What each possible result means

“Supply upgrade” can describe very different work.

A 100-amp fuse is not a universal requirement. National Grid Electricity Distribution standardised domestic cut-outs in its area at 80 amps from 1 June 2023 because sustained low-carbon loads changed the thermal assumptions behind some earlier 100-amp arrangements. Other network operators publish different fuse options.

Good to know

Do not open the sealed cut-out to identify the fuse. If its rating is unclear, the installer should ask the network operator or provide a photograph taken safely without touching the equipment.

Who contacts the network operator, and when?

The process should start before a final installation date is promised.

1. The installer selects the system. The design identifies the heat pump, its electrical input and any auxiliary heaters.

2. The installer or electrician checks the property. This includes maximum demand, the consumer unit, main fuse, service arrangement and the model’s entry on the Energy Networks Association register.

3. The installer chooses the connection route. A Great Britain installation can use “Connect and Notify” only when all applicable Energy Networks Association conditions are met. These include known suitable service equipment, no relevant looped-service or safety issue, demand within the permitted connection limit, a heat pump system of no more than 32 amps and a model marked for that route. Other cases require an application first.

4. The network operator assesses non-routine work. It may approve the connection, request information, visit the property or quote for an upgrade. Network approval remains separate from the private contract with the installer.

5. Each party completes its work. The network operator handles its fuse and service equipment. The supplier or meter operator handles relevant meter equipment. The electrician completes and certifies the internal installation.

In Northern Ireland, NIE Networks requires every heat pump application to be made before installation. The installer submits it through Energy Networks Association Connect Direct so NIE Networks can assess the equipment and existing supply.

How much could the electrical work cost?

There is no fixed UK-wide price. Cost depends on whether the work is limited to internal wiring, involves a straightforward fuse change, or requires a new service cable, excavation or three-phase connection.

Some network operators provide certain fuse or service-readiness work without charge. Chargeable alterations are assessed individually. UK Power Networks says cost and timing depend on the specific upgrade. Scottish and Southern Electricity Networks (SSEN) says fuse upgrades can be free in its area, while larger connection quotes may include materials, engineering work and road closures.

The installer’s price is separate from the network quote. It may include the dedicated circuit but exclude consumer-unit, meter, trenching or later remedial work. The quotation should state what is included, what is provisional and who pays if additional work is identified.

MCS’s February 2026 guidance says quotations should include the work and cost breakdown, product specification, timeline and total price including Value Added Tax (VAT). Its contract guidance also covers permissions, extra costs and charges for unforeseen work.

What should be confirmed before signing?

Ask for these points in writing, as part of the quotation or contract where applicable:

• the heat pump model, supply phase and maximum electrical input;

• the calculated whole-property maximum demand;

• the confirmed fuse rating and whether the service is looped;

• all internal electrical work included in the price;

• who submits the network application and pays for quoted work;

• whether dates depend on network, supplier or property-owner approval;

• what happens if the necessary upgrade changes the price materially.

A qualified electrician assesses the internal installation. The MCS installer manages the heat pump design and MCS requirements. The network operator decides the capacity of its connection assets. Tenants and leaseholders may also need authority from the landlord, housing provider or freeholder.

Key takeaways

• A heat pump does not automatically require a supply upgrade.

• The exact model, whole-home demand and existing equipment decide the answer.

• A larger fuse, internal work and three-phase power are separate possibilities.

• Heating output is not a substitute for maximum electrical input.

• The installer should use the correct network notification or approval route.

• Costs and timing should be itemised before contract.

Frequently asked questions