An air source heat pump on a paved patio behind a Victorian brick terrace

A Heat Pump in a Victorian Terrace: What It Takes

The grant, the planning rules, the design, the solid walls and the real costs of taking a London Victorian terrace off gas during a renovation.

By Alstruct Ltd · Published 2026-11-03

Retrofit Published 3 November 2026 · 10 min read

In short: An air source heat pump can heat a Victorian terrace well if the house is designed around it: a room-by-room heat loss calculation, emitters sized for low flow temperatures (underfloor heating or larger radiators), sensible insulation that respects solid walls, and good ventilation. In England the Boiler Upgrade Scheme gives £7,500 off an air-to-water heat pump (£9,000 for eligible off-gas homes until 31 March 2027), most houses can install one under permitted development, and the median installed cost through the scheme in 2025/26 was about £13,000 before the grant.

Can a Victorian terrace run on a heat pump?

Yes. Historic England's 2024 advice note on adapting historic buildings describes heat pumps as generally acceptable if they are sympathetically sited. What decides success is the design: a terrace loses heat through solid brick walls, single glazing, suspended floors and draughts, so the heat pump has to be sized to the house as it will be after the renovation, not before.

The grant: Boiler Upgrade Scheme in 2026

£7,500 off an air-to-water or ground source heat pump; £2,500 for air-to-air. From 21 July 2026 to 31 March 2027, eligible off-gas homes get £9,000.
Your MCS-certified installer applies for it and deducts it from the price.
You must own the property, and the heat pump must replace fossil fuel or direct electric heating and provide all of the space heating and hot water. Hybrid systems are excluded.
There is currently no insulation or EPC condition, although Ofgem points out that heat pumps work best in a well-insulated home.
Heat pump installations are zero-rated for VAT until 31 March 2027.

Planning permission in London

Most houses can install an air source heat pump under permitted development. Rules that changed on 29 May 2025 removed the old requirement to keep the unit at least 1 metre from the boundary and raised the size limit to 1.5 m³. A terraced or semi-detached house can have one unit.

The unit must meet the MCS 020(a) noise standard (37 dB(A) at the neighbour's window). Many websites still quote the old 42 dB figure.
Not on a pitched roof; on a flat roof, at least 1 metre in from the edge.
In a conservation area, not on a wall or roof facing a highway, or nearer the highway than the house.
Listed buildings have no permitted development rights for heat pumps, and Article 4 directions can remove them.

In a terrace the usual place is the rear garden or the side of the back extension, away from the street.

Design: heat loss, flow temperature and emitters

MCS installation standards require a room-by-room heat loss calculation to BS EN 12831. Approved Document L asks for a new or fully replaced wet heating system to be designed for a flow temperature of 55°C or lower, and lower flow temperatures make a heat pump more efficient. In practice that means underfloor heating where floors are being dug up anyway, and larger radiators elsewhere; many existing radiators are too small.

Space for a hot water cylinder, usually in a cupboard on the first floor or in a loft
An electrical supply check: some units can be fitted and the network operator told afterwards, others need approval first
A position for the outdoor unit that suits both noise and the planning rules

Solid walls: insulate with care

Victorian walls are solid brick that takes up moisture and dries out again. Historic England warns that insulating them changes how they behave and can create or worsen damp, and research summarised from the Society for the Protection of Ancient Buildings found internal insulation leaves the outer masonry colder and wetter. The safer approach is vapour-open, breathable materials, such as wood-fibre boards with lime plaster, installed only on dry walls, and breathable paints.

As a house becomes more airtight, ventilation matters more. Approved Document F says energy efficiency work must not leave ventilation worse than before, and points to mechanical extract or mechanical ventilation with heat recovery (MVHR) once a home is airtight.

From our projects: Wimbledon Victorian terrace: extension, loft and low-carbon refit. A three-bedroom terrace was taken off gas: an air source heat pump feeds underfloor heating downstairs and radiators upstairs, MVHR keeps the air fresh, and the front wall was insulated with wood fibre and lime plaster once the masonry was below 15% moisture.

In a renovation, sequence matters

Fix the insulation and glazing design first, then do the heat loss calculation.
Run first fix pipework and underfloor heating manifolds before screeds and plaster.
Install radiators and the cylinder with second fix.
Commission the heat pump last, once every emitter is in, so the flow temperatures and balancing match the finished house.

What it costs to install and run

Nesta's analysis of the Boiler Upgrade Scheme found a median installed cost of £13,041 in 2025/26, about 11% lower than in 2022, which leaves around £5,500 to pay after the £7,500 grant. Underfloor heating, larger radiators and a cylinder in a renovation are extra and depend on the house.

On the October to December 2026 price cap, electricity costs 26.32p per kWh and gas 7.97p per kWh. A heat pump with a seasonal efficiency of 3 produces heat at about 8.8p per kWh, against about 9.4p for a gas boiler at 85% efficiency, and coming off gas removes the gas standing charge of roughly £108 a year. One supplier reports an average seasonal efficiency of 3.91 across its customers' installations; that is its own data.

Frequently Asked Questions

Do I need planning permission for a heat pump in London?

Usually not for a house, if the unit meets the MCS 020(a) noise standard and is sited correctly. You will need permission for a listed building, a pitched roof position, or where an Article 4 direction removes the rights, and in a conservation area the unit cannot face the street.

Do I need to insulate before getting a heat pump?

It is not a condition of the Boiler Upgrade Scheme, but it lowers the heat loss, the size of the unit and the flow temperature, which makes it cheaper to run. In a Victorian house, use breathable insulation on dry walls.

Will my old radiators work with a heat pump?

Only if they are large enough for the lower flow temperature. Many need replacing with larger radiators, and underfloor heating works well where floors are being replaced anyway.

How noisy is an air source heat pump?

Under the permitted development rules the unit must meet the MCS 020(a) standard of 37 dB(A) at the neighbour's nearest window.

Is a heat pump cheaper to run than gas?

Usually, at late 2026 prices and with good design: a heat pump with a seasonal efficiency of 3 produces heat for about 8.8p per kWh, against about 9.4p for a typical gas boiler, before removing the gas standing charge.

Sources

This guide is general information, checked against the sources above on 3 November 2026. Every house is different, so take advice on your own property before starting work.

Going off gas?

Plan the heat pump into your renovation

We build the insulation, pipework, underfloor heating and ventilation around the heat pump design, so it works from the day it is commissioned.

Book a Consultation Call 020 8080 8240

CHAS Elite · Constructionline Gold · FMB member · 5.0 on Google