Heat Pump for an HMO: A Landlord Guide

What this guide covers and does not

This guide covers the points that can be checked on official sources: how HMOs are defined and licensed, which duties sit with HMO landlords, and what a heat pump changes. It does not cover every council’s local rules, and it is not legal advice. HMO rules vary by area, so the council is the final authority.

The short answer

A heat pump in an HMO is a design problem before it is a cost problem. The heat pump itself is the same technology. The difficulty is that HMOs usually have several tenancies, shared or per room heating, and a licence with conditions.

What is verified about HMOs

• Definition. GOV.UK says an HMO is a property where at least 3 tenants live, forming more than one household, and they share a toilet, bathroom or kitchen.
• Large HMOs need a licence. GOV.UK says at least 5 tenants from more than one household makes it a large HMO, and large HMOs need a licence from the local council.
• Mandatory licensing from 2018. Government guidance for councils confirms that, from 1 October 2018, mandatory licensing is not limited by number of storeys. It applies where 5 or more people from 2 or more separate households live in the building.
• Councils can go further. The same guidance says a council can designate an area for additional HMO licensing, covering HMOs not subject to mandatory licensing.
• Extra duties. GOV.UK says that in large HMOs the landlord must make sure the property meets certain standards, on top of the ordinary repair and safety duties.

That guidance is dated 2018, so check your council’s current scheme.

Why heat pumps are harder in an HMO

These points are practical observations, not legal rules.

• Heating is often per room. Some HMOs rely on electric panel heaters or a mix of systems. A heat pump normally feeds a central heating circuit with radiators or underfloor pipes. If none exists, the cost of adding one needs to be priced.
• Shared heating means shared bills. If tenants share one system and one meter, who pays, and how it is split, has to be settled before the heat pump goes in.
• All inclusive rents move the risk. If your rent includes bills, you carry the running cost, which makes the efficiency of the system your problem. At the Ofgem cap from 1 October to 31 December 2026, electricity is 26.32p per kWh and gas is 7.97p, so a poorly performing heat pump will cost you more than the boiler it replaced.
• Space. An outdoor unit needs a place that meets the permitted development limits, including a 37.0 dB(A) noise limit and one unit on a house that is not detached. Flats are limited to a smaller compressor volume. Councils can remove these rights with an Article 4 direction.
• Turnover. Many HMOs have regular tenant changes. A system that needs tenant understanding to run well, such as low and steady heating, needs a clear handover.

Worked example (modelled, not a real project)

Inputs: a five bed HMO that needs 20,000kWh of heat a year (an assumption for illustration, not a measured figure), rent that includes bills, gas boiler at 90% efficiency, and Ofgem cap rates from 1 October to 31 December 2026. Standing charges are left out.

Heating	Energy used	Yearly cost to the landlord
Gas boiler, 90%	22,222kWh gas	£1,771
Heat pump, SCOP 3.0	6,667kWh electricity	£1,755
Heat pump, SCOP 2.5	8,000kWh electricity	£2,106

The point of the table is the last row. A heat pump that performs a little worse than hoped moves about £350 a year onto the landlord in a bills included let. Ask for the installer’s heat loss calculation and the SCOP they expect for this building.

Options to put to an installer

Option	Fit for an HMO	Points to check
Air to water heat pump on a central circuit	Best where radiators already exist	Grant is £7,500; sizing for the whole building; metering
Air to air units (room by room)	Suits per room heating	Grant is £2,500; must replace existing heating; see air to air for rentals
Hybrid	Not grant funded	Not eligible for the Boiler Upgrade Scheme
Fabric improvements and keep the boiler	Often sensible	Cost, EPC effect and tenant comfort

One grant is available per property, so a single HMO building is likely to get one grant, not one per room; confirm with the installer.

What to ask the local council

Ask in writing and keep the replies.

1. Is the property licensed, and is it in an additional or selective licensing area?
2. Do the licence conditions mention heating, and would changing the system change the licence?
3. Is there an Article 4 direction or other planning limit that affects an outdoor unit?
4. Does building control need to be involved for the heating or electrical work?
5. Which safety certificates must be kept up to date after the change? See gas safety and heat pumps.

When a heat pump is NOT the right answer

• The building has no wet heating system and the tenancy mix makes a retrofit impractical.
• The rent includes bills and the home leaks heat. Fix the fabric first.
• Tenancies change frequently and there is no agreed way to split bills.

In those cases a boiler replacement with fabric work, or room by room air to air units, may be more realistic.

Next step

Work out what your layout might cost in the landlord calculator, or send an enquiry through the quote page. Relevant independent firms contact you, no charge to you and no obligation.