Heat Pump vs Air Conditioner Cost Calculator

How this calculator works

This calculator works in ranges rather than single figures, because real quotes, yields and tariffs genuinely vary that much. It starts from typical UK price, output and savings ranges drawn from published 2026 industry guides and official scheme documentation, then scales them by the quantities you enter and adjusts them for each choice you make below. The result is a low-to-high band that a realistic outcome is likely to fall within, not a promise of the figure you will achieve.

These are two flavours of the same technology doing different jobs: an air-to-water heat pump at to installed replaces your boiler entirely, heating radiators and hot water, while air conditioning, air-to-air heat pumps at to for three to four rooms, heats and cools room air directly but cannot touch radiators or hot water. From 28 April 2026 both attract support, the Boiler Upgrade Scheme grant for air-to-water and a new grant for air-to-air, one grant per property.

Home size

Home size scales the installation estimates: larger homes need higher output units, more emitters and more labour, while flats and small houses sit below the typical three bedroom baseline that published guide prices describe. It does not scale the running cost estimates here, which follow the annual heat demand figure you enter instead.

Annual heat demand (kWh)

This is the heat your home needs over a year for space heating and hot water, not the fuel you buy. A typical UK three bedroom house needs roughly 10,000 to 14,000 kWh of heat a year; if you currently heat with gas, your annual gas kWh from your bill multiplied by about 0.85 (boiler efficiency) is a reasonable estimate of heat demand. Well insulated homes sit far lower and large or draughty ones far higher, and every running cost figure on this page scales directly with this number.

Where you live

Installation labour is not priced uniformly across the UK, with published guides putting London and South East quotes roughly 15 to 25 percent above the national average. Hardware prices are broadly national, so the difference sits mostly in labour, access and overheads.

Heat pump electricity tariff

The heat pump’s running cost depends heavily on its tariff: standard rates sit around 24.7 to 26.1 pence per kWh under the 2026 caps, while dedicated heat pump and time-of-use tariffs cut the effective rate by a quarter or more through cheap windows and smart scheduling. The comparison system’s fuel is priced at standard rates throughout, so the tariff choice here shows how much of the gap smart tariffs can close or open.

What else affects the figures

Running efficiency is similar, since both move heat rather than generating it, so annual costs for the same delivered heat overlap heavily and the real differences are functional. Air-to-air wins on cooling, which no wet heat pump provides, on room-by-room control and on installation speed, often a single day per room; air-to-water wins on whole-house heating through existing radiators, hot water, and eligibility for the far larger grant. A growing pattern in well insulated smaller homes is air-to-air heating plus a small cylinder solution for hot water, while most family homes replacing a boiler land on air-to-water, sometimes adding a single air conditioning unit later for summer bedrooms. The honest comparison is less either-or than which jobs need doing.

Certification, planning and grid connection

Air conditioning installation is legally restricted to F-Gas certified engineers, since the refrigerants involved are controlled fluorinated gases, and it is a criminal offence to install or service systems without certification, so check the register before hiring. The outdoor condenser is normally permitted development on a house if it is under 0.6 cubic metres, not on a wall facing the highway and at least a metre from the boundary, but flats, listed buildings and conservation areas typically need permission and some councils apply noise conditions. From 28 April 2026, eligible air-to-air heat pump installations replacing fossil fuel heating can claim a 2,500 pound Boiler Upgrade Scheme grant, one grant per property.