How much do solar panels for landlords cost?

The first thing to understand about the cost of solar for a rental property is that it is priced and sized differently from solar on an owner-occupied home. A homeowner sizes a system to their own electricity bill and chases the bill saving. A landlord usually cannot do that, because in most lets the tenant pays the electricity, not the landlord. So the right system is the one sized to the EPC model and to who actually pays the bill, not the one a national installer would sell a homeowner. Get that wrong and you over-spend on capacity the tenant benefits from. Get it right and the numbers are sensible and defensible.

For a standard buy-to-let house, a 3 to 4 kW array (roughly 7 to 12 panels) costs about £5,000 to £9,000 fully installed in 2026, including scaffolding, the inverter, fitting, certification and the DNO notification. That is the workhorse system for most single lets and the size that models cleanly into the route to EPC band C alongside a few hundred pounds of loft or cavity insulation. A bills-inclusive HMO is a bigger and more rewarding job: a 4 to 8 kW system runs £7,000 to £14,000, and because the landlord is the bill payer in a bills-inclusive HMO, a battery genuinely pays here, adding £2,500 to £5,000 but earning its keep through self-consumption. Mixed-use buildings with a shop or office below flats can take a 5 to 15 kW array at £8,000 to £25,000, with the commercial daytime load giving strong self-consumption.

Cost per kW by system size

As a rough guide for residential and small-commercial rooftop work in 2026, expect around £1,300 to £1,700 per kW on the smallest 3 to 4 kW domestic arrays, falling to roughly £1,000 to £1,300 per kW on larger HMO and mixed-use systems where the fixed costs (scaffolding, survey, design, the inverter) are spread across more panels. This is why a portfolio roll-out, where one survey programme and bulk procurement cover several properties, lowers the per-unit cost compared with treating each property as a one-off.

What the landlord actually gets back

Be clear-eyed here, because this is where landlords get mis-sold. In a standard single let where the tenant pays the electricity, you do not get the energy-bill saving. The tenant does. Your return comes from four other places. First, the EPC band uplift toward the mandatory band C by 1 October 2030 under the Warm Homes Plan, which is the reason most landlords are doing this at all. Second, lettability and rent: a lower-running-cost, higher-EPC home lets faster, attracts better tenants and is easier to defend at rent review. Third, the Smart Export Guarantee. Solar exported to the grid earns money under the SEG, typically 3 to 15p per kWh in 2026 depending on the supplier, and where the system is registered in the landlord's name, that income accrues to the landlord rather than the tenant. Register it correctly and it is one of the few direct cash returns from a tenant-paid let. Fourth, asset value: lenders and buyers increasingly price EPC risk, so a compliant, solar-equipped property holds its value and refinances more easily.

Where you do pay the electricity, the calculus changes completely. In a bills-inclusive HMO, communal-supply block, or the commercial floor of a mixed-use building, self-consumption returns real cash. A 7 kW array plus a battery on a bills-inclusive HMO with all-day occupancy can self-consume 60 to 70% of what it generates, which is why payback on those systems can land around 6 to 7 years rather than being measured in EPC points. The single most important question before sizing anything is therefore: who pays the electricity bill?

The £10,000 cost cap and how to sequence works

Under the Warm Homes Plan, landlords in England are expected to spend up to £10,000 per property to reach band C, and qualifying works (solar PV, insulation, low-carbon heating, LED lighting) count toward that cap. Crucially, improvements made from October 2025 onward already count, so works you do now are not wasted. The right approach is to sequence the cheapest band-moving measures first, usually loft and cavity insulation, then add a solar array sized to clear the band and generate income inside the remaining envelope. On harder stock with expensive solid walls, solar plus loft insulation is often the way to reach C without triggering costly wall work that would blow the cap.

Tax: it depends entirely on how you hold the property

If your portfolio is held in a limited company (an SPV), solar is qualifying plant and machinery, and the company can claim the Annual Investment Allowance, 100% relief on the first £1m of qualifying spend, with the 50% First Year Allowance available above that. At current corporation tax rates that can mean an effective saving of around a quarter of the cost in year one. If you hold the property personally as a residential let, you cannot claim capital allowances: the furnished holiday let regime and its allowances were abolished from April 2025, leaving only Replacement of Domestic Items Relief for furnishings. The structure decides the relief, so we flag it and your accountant confirms it. See the detail on our grants and funding page. You can read the official position on capital allowances, and the SEG framework on the Smart Export Guarantee guidance.

Financing the spend

Most landlords fund solar from cash or refinance, treating it as planned capex against the 2030 deadline rather than a discretionary green purchase. For incorporated portfolios, the capital allowance position improves the cash cost. Asset finance can spread the cost over several years and is worth considering for a programmed roll-out across a portfolio, where it lets you upgrade more units per year ahead of the installer bottleneck. Power purchase agreements, common on large commercial roofs, rarely suit residential lets because the saving accrues to the bill payer (the tenant), not the landlord, so for most rental work a capital purchase or asset finance is the sensible route.

Hidden costs and what drives variation

The headline price assumes a sound roof. If the covering is near end of life, asbestos cement, or structurally marginal, you may need a re-roof or strengthening first, which adds cost but is often worth combining with the install. Other variables: scaffolding access on a terraced street, a DNO G99 application for systems above 3.68 kW per phase (which adds weeks and applies before installing), older single-phase supplies that constrain combined solar plus heat pump or EV loads, and freeholder or leaseholder consent on flats, which costs nothing directly but can stall a project. We price all of this transparently at survey rather than springing it later.

Typical timeline and cash flow

A standard rooftop install on a single let is one to two days on site once surveyed, with the whole process from survey to commissioning usually two to six weeks. Larger arrays needing G99 approval take longer, and flats needing freeholder consent longer still. For a portfolio, we run a programmed schedule across units to beat the pre-2030 bottleneck and spread your capex across tax years. The cash flow profile is front-loaded capex against a long tail of EPC compliance, retained SEG income, and protected rent and asset value, plus, where you pay the bills, a direct energy saving from day one.