HMOs (Houses in Multiple Occupation): Solar panels for landlords

Why a bills-inclusive HMO is the single best landlord solar case

If you let on a bills-inclusive basis, an HMO is the strongest solar case in the whole private rented sector, and it is the one where the usual landlord objection simply does not apply. In a standard single let the tenant pays the electricity bill, so the landlord pays for the panels while the tenant captures the saving, which is the split-incentive problem at the heart of landlord solar. In a bills-inclusive HMO that problem disappears entirely, because the landlord is the bill payer. Every kilowatt-hour the array generates and the house consumes is a kilowatt-hour the landlord does not have to buy, so self-consumption returns directly as landlord cash. That is why HMOs are where solar panels for landlords pay back fastest.

HMOs also have the right load shape for solar. A house of multiple occupation runs a high shared daytime demand from the communal kitchen, hot water, heating, broadband and lighting, and that daytime load lines up well with daytime generation, lifting self-consumption further. It is the one landlord scenario where a battery becomes genuinely economic, because the landlord keeps the saving the battery unlocks. On top of the cash return, a 4 to 8 kW array combined with insulation helps clear the EPC C standard ahead of the 2030 deadline, and lower running costs are a strong tenant-acquisition signal in a competitive student and professional market.

The contrast with a standard single let is worth dwelling on because it is the whole point. On a tenant-pays single let, solar is fundamentally a compliance and asset-value measure with a modest export income on top, and we size it conservatively for exactly that reason. On a bills-inclusive HMO the same physical array does something quite different: it offsets electricity you are buying every day, so the avoided import is cash that lands directly with you, the landlord. That is why an HMO can justify a larger array and a battery where a single let cannot, and why the payback figure on an HMO is the strongest in the whole private rented sector. If you run a mixed portfolio, the HMOs are usually where your first solar capital should go, because they are the units where the return is real money rather than a deferred asset benefit, and the compliance gain comes as a bonus on top of the cash.

What a typical install looks like and how we size it

For an HMO we usually design a system in the 4 to 8 kW range, which is roughly 10 to 18 panels across about 20 to 45 square metres of roof. A system that size generates in the region of 3,500 to 7,200 kWh a year and saves somewhere between 0.8 and 1.6 tonnes of CO2 annually. Because the landlord is the bill payer on a bills-inclusive HMO, we size aggressively for self-consumption rather than to the bare EPC model, since here the avoided import is real cash to you. We pull the property usage data to match the array and a battery to the all-day occupancy pattern, so that midday generation can power the evening communal load rather than being exported at a lower rate. This is the one part of the portfolio where adding storage is usually the right call.

Costs, payback and tax relief

An HMO project typically lands between 7,000 and 14,000 pounds for a 4 to 8 kW system, with a battery adding to that where it pays, and a simple payback near 6 years, the best in the private rented sector, precisely because the landlord captures the saving. The return is driven by avoided import rather than export, which is the better position to be in, and the Smart Export Guarantee covers any surplus. On tax, the ownership structure decides the relief: a personally-held HMO cannot claim capital allowances on the panels (the furnished holiday let regime and its allowances were abolished from April 2025), whereas an HMO held in a limited company (an SPV) can use the Annual Investment Allowance (100% up to 1m pounds) and potentially the 50% First Year Allowance on qualifying plant. Confirm the position with your accountant. Our cost guide works through the HMO numbers with and without a battery.

Funding routes in detail

The Smart Export Guarantee pays the landlord account, typically 3 to 15p per kWh in 2026, for surplus exported beyond what the house consumes, though on a well-sized HMO most generation is self-consumed. Where individual occupants qualify on a means-tested benefit, ECO4 (to December 2026) can fund insulation and heating at no cost to the tenant with your consent, and the Warm Homes: Local Grant (to 31 March 2028) is available to a privately renting tenant on a household income of 36,000 pounds or less in an EPC D to G property through the local authority with your permission. These tenant-led routes help stack fabric measures onto the self-funded array to clear band C. For incorporated HMOs, capital allowances are the genuine tax advantage on the solar spend itself, which makes the already-strong HMO case stronger again.

The interaction between the tax position and the cash return is what makes an incorporated HMO such a strong case. Because the array on a bills-inclusive HMO is offsetting electricity you genuinely buy, the saving is real cash from day one, and where the property sits in a limited company that same qualifying spend can attract the Annual Investment Allowance, so a slice of the capital comes back as a corporation-tax saving in year one as well. You are therefore getting the operational saving and the tax relief on the same outlay, which is not something a personally-held single let can claim. We always flag this for your accountant to confirm rather than assert it, because the entitlement turns on your structure, but for the many portfolio landlords who incorporated after Section 24 and run bills-inclusive HMOs, this combination is one of the clearest positive returns available anywhere in the private rented sector.

Compliance and sector considerations

HMOs carry their own additional or mandatory licensing conditions, separate from solar, and those continue to apply. For the array itself, an MCS-certified install is required for SEG eligibility, Part P (electrical) and Part A (roof loading) apply, and because HMO arrays are larger, anything above 3.68 kW per phase needs DNO G99 approval submitted before installation, so allow a few weeks for that. The domestic MEES regime (EPC C by 1 October 2030, 10,000 pound cap) applies as it does across the sector, and improvements from October 2025 already count toward the cap. As elsewhere, fabric measures move the new fabric-based EPC more per pound than PV, so we pair the array with the cheapest insulation to clear band C rather than relying on solar alone. The good news is that on a bills-inclusive HMO the compliance spend and the cash-saving spend point in the same direction.

How we approach this kind of project

We confirm first that the HMO is genuinely bills-inclusive, because that is what turns the economics from a compliance exercise into a strong cash return. We then size for self-consumption from the real all-day load, model a battery against the evening communal demand, and pair the array with the cheapest fabric measures to clear band C inside the cap. We check the roof loading and any asbestos before quoting a fixed price, and we submit the G99 application early because HMO arrays usually need it. You get a fixed-price proposal, an insurance-backed warranty, and where the property is held in a company we flag the capital-allowance angle for your accountant to confirm. We also document the install so the lower running costs can be used as a tenant-acquisition point.

The battery sizing on an HMO is where the half-hourly data really earns its keep, because a battery is only worth what it lets you shift from cheap or self-generated daytime power into the evening peak when the house is full. We look at the genuine occupancy pattern, a student HMO empties during term-time days and fills in the evening, a professional HMO may carry a steadier all-day load from home-working, and we size the storage to that shape rather than to a generic figure. Over-sizing a battery wastes capital that never cycles; under-sizing it leaves evening demand drawing from the grid at full price. Getting that balance right is what lifts self-consumption into the range where the HMO payback genuinely comes in at the better end. We also plan the install around a working, occupied house, coordinating access and scaffolding so that communal services are not disrupted, because an HMO cannot simply be emptied for the works.

An illustrative example

As an illustrative composite based on typical UK HMO projects: a six-bed professional HMO let on a bills-inclusive basis, where the landlord pays the energy, carried a high shared daytime load from the communal kitchen, hot water, heating and broadband, and the landlord wanted to cut a substantial electricity bill while strengthening the EPC. A 7.0 kW array of around 16 panels plus a 10 kWh battery generated in the region of 6,400 kWh a year. With all-day occupancy and the battery shifting midday generation into the evening, self-consumption sat around 70%, the EPC moved from E to C with added cavity insulation, and the payback came in near 6.5 years. The lower bills were used as a marketing point that cut voids in a competitive HMO market, and the split-incentive problem disappeared entirely because the landlord paid the bill. The figures are illustrative and depend on your house, occupancy, tariff and roof.

The takeaway for HMO landlords is simple: where you pay the bills, solar is no longer a reluctant compliance cost but one of the better investments you can make across the portfolio, returning real cash every day while clearing the EPC standard as a side effect. If your portfolio also includes single lets or shared-roof flats, where the maths is different, see solar for buy-to-let houses and solar for rental flats. When you are ready, see the cost guide, the grants and funding options, or request a free feasibility, and read the landlord solar FAQs first.