Heat pumps for landlords in Portsmouth

A terraced, rented, island city

Portsmouth has 24,669 privately rented households out of 86,155, which is 28.6% (2021 Census). Owner-occupiers are 52.3% and social tenants 18.0%. Those shares look ordinary. The housing stock does not.

Terraced homes are 43.4% of households, about 37,400, second only to Hull among the cities on this site. Purpose-built flats are 26.5% (about 22,800) and converted or shared houses 6.3% (about 5,400). Semi-detached homes are only 16.5% and detached homes 4.5%. Put together, seven in ten Portsmouth households live in a terrace or a block of flats, and fewer than one in twenty in a detached house.

That matters for a heat pump in three ways:

• Space. A terrace in Southsea, Fratton or North End usually means a small rear yard. The outdoor unit needs a position that clears the neighbour’s window and still meets the noise limit.
• One unit only. Under the England permitted development rules a house that is not detached may have one unit, against two on a detached house. With detached homes at 4.5%, almost every Portsmouth rental falls under the one-unit rule.
• Flats. A compressor on a block of flats is limited to 0.6 cubic metres, against 1.5 cubic metres on a house, and you will normally need the freeholder’s consent. Read heat pumps for flats before you price anything.

These percentages cover all households, not only rented ones, so treat them as the backdrop and check your own address.

Gas and electric heating in Portsmouth

Mains gas heats 75.8% of homes, about 65,300 households. Electric-only heating is 11.5%, about 9,900, which is a higher share than Nottingham’s or Leicester’s 11.0%. District heating is 0.9%, no central heating 2.4% and oil 0.0%.

Two conclusions follow. First, the £9,000 Boiler Upgrade Scheme rate needs oil or LPG heating with no mains gas connection, and with 0.0% of homes on oil it will almost never apply in the city. Plan on £7,500. Second, the electric-only flats and bedsits are where the running-cost case is strongest, as the example below shows.

Worked example (modelled, not a real project)

Inputs: a one-bedroom flat using 5,000kWh of heat a year (an assumption for a small flat), electricity at 26.32p per kWh (Ofgem cap, 1 October to 31 December 2026), direct electric heating at 100% efficiency and a heat pump at SCOP 3.0 or 3.5. Standing charges are left out because the tenant pays them whatever the system.

Heating	Electricity needed	Cost a year
Direct electric or storage heaters	5,000kWh	about £1,316
Heat pump, SCOP 3.0	1,667kWh	about £439
Heat pump, SCOP 3.5	1,429kWh	about £376

The single cap rate overstates the storage heater cost if the tenant is on a cheaper off-peak tariff, so the real gap is smaller. The saving goes to whoever pays the bills. For you, the gain is a stronger EPC option. The catch in a flat is the unit position and the freeholder, not the sums. If an air-to-water system cannot go in, an air-to-air system is funded at £2,500 where it replaces existing heating, but it does not heat hot water. See air-to-air heat pumps for rental properties and storage heaters vs heat pumps.

Every HMO in Portsmouth needs a licence

Portsmouth City Council runs additional licensing, and the council says all HMOs in the city have needed a licence since 1 September 2023. There are three types:

• Additional licence: HMOs of 3 or 4 people, and HMOs of 3 or more people in a purpose-built flat within a block of 3 or more flats.
• Mandatory licence: HMOs of 5 or more people.
• Section 257 licence: a building converted into flats that does not meet the 1991 Building Regulations, where two thirds or more of the flats are rented out.

The council says failing to licence is an offence under section 72 of the Housing Act 2004, with civil penalties and rent repayment orders; GOV.UK guidance says the maximum civil penalty for licensing offences rose from £30,000 to £40,000 for offences on or after 1 May 2026. A licence carries conditions, so confirm your status before planning works and ask the council whether a change of heating system affects the licence conditions.

Article 4: new HMOs need planning permission

Portsmouth’s Article 4 direction (reference Art 4/HMO/01) came into force on 1 November 2011 and covers every family dwelling in the city. Changing a house to a small HMO for 3 to 6 unrelated sharers needs planning permission. This is a citywide rule, unlike the area-based directions in Plymouth or Hull, so there is no part of Portsmouth where a conversion can rely on permitted development. If you are thinking of converting and re-heating together, the planning answer comes first.

Conservation areas and seafront terraces

Portsmouth City Council lists 30 conservation areas, many of them in Southsea, including Owen’s Southsea, The Terraces, East Southsea and Craneswater and Eastern Parade, plus Old Portsmouth. The heat pump permitted development rights carry extra limits in a conservation area, and a listed building needs consent. Check the address on the council’s conservation map before choosing a unit position, especially for a wall facing the street.

EPC C by 2030 for Portsmouth rentals

Today the legal minimum is EPC E, with a cost cap of £3,500 including VAT. The government plans EPC C by 1 October 2030 with a £10,000 cost cap per property, but the regulations have not been laid. Read EPC C 2030 and your heating choice and the cost cap and exemptions.

For an older Portsmouth terrace the cheaper EPC steps are often loft insulation, draught-proofing and heating controls. Insulation first is often the right answer, and does a heat pump improve an EPC rating explains how the assessment treats the heating system.

Portsmouth City Council declared a climate emergency in 2019 and set a target of net zero for its own operations by 2030, guided by its 2030 climate change strategy. That is a council plan, not a duty on landlords.

Grants for Portsmouth landlords

• Boiler Upgrade Scheme: £7,500 for an air-to-water or ground source heat pump. Landlords are eligible and an MCS installer applies on your behalf. See the BUS page for landlords.
• Warm Homes: Local Grant: GOV.UK lists Portsmouth as the lead council for a consortium of 31 member councils, stretching from the south coast to Bedford, Luton and Rutland, with £34,807,254 allocated. The local scheme, Switched On Portsmouth, offers measures including solid wall insulation, solar panels and air source heat pumps, with a household income route of £36,000 or under. It says landlords must own no more than four properties, that it is not taking new applications now, and that more funding is expected in spring 2027. Read the Warm Homes Local Grant page for the national landlord terms.
• Warm Homes Loan Scheme: a lender loan, not a grant.

When a heat pump is the wrong answer

• A mid-terrace with no yard, or a yard where the unit would sit under a neighbour’s bedroom window.
• A flat where the freeholder will not consent.
• A licensed HMO where the conditions or planning status are still unresolved.
• A gas-heated home with thin insulation where tenants would pay more at 26.32p per kWh.

If a heat pump does suit the property, send an enquiry and relevant independent firms contact you, with no charge to you and no obligation. Or test it first with the landlord heat pump calculator.