How do HMO mortgages differ from standard buy to let?

Why lenders treat HMOs as a different product

A house in multiple occupation is let by the room to three or more tenants from more than one household. Rents are higher than a single let, but so are voids, wear, management effort and regulatory exposure. Lenders price for that. Mainstream buy to let lenders often decline HMOs outright, so the market is a smaller panel of specialist lenders, and rates typically run 0.5% to 1% above standard buy to let. Arrangement fees are also more often percentage based, commonly 1% to 3% of the loan.

The numbers side by side

Take a £300,000 property with a 75% loan of £225,000, for illustration. As a single let it might achieve £1,300 a month. As a 6 room HMO at £550 a room it achieves £3,300 a month. On a standard buy to let 5 year fix at 4.59%, interest is £10,327.50 a year, about £861 a month. On an HMO product at 5.49%, interest is £12,352.50 a year, about £1,029 a month. The HMO costs £168.75 a month more in interest, and the rent is £2,000 a month higher. That gap is why the sector exists, and also why lenders scrutinise whether the room rents are sustainable for the location rather than taking them at face value.

The stress test works the same way as standard buy to let, typically 125% of the interest at the stress rate for limited companies. Here 125% of £1,029 is about £1,287 a month, which £3,300 clears easily. HMO cases rarely fail on rent; they fail on property, licensing or experience. Our buy to let affordability calculator shows what any rent figure supports.

Licensing is underwritten, not assumed

Mandatory licensing applies to HMOs with 5 or more occupants from 2 or more households, and many councils run additional or selective schemes that catch smaller HMOs too. Lenders check that the correct licence is held or applied for, and an unlicensed licensable HMO is unmortgageable with most of the panel. Article 4 directions, which remove permitted development rights for converting family homes to small HMOs, are also checked, since they affect both value and the ability to replace tenants.

Two valuation bases

Small HMOs, typically up to 6 rooms without major structural alteration, are usually valued on a bricks and mortar basis, meaning what the house would fetch as a house. Larger or heavily adapted HMOs may be valued on a commercial or yield basis, capitalising the rental income, which can produce a value well above the vacant possession figure. The basis matters: a 75% loan against a yield valuation of £400,000 is a very different sum from 75% of a £300,000 bricks and mortar figure. Which basis applies is the valuer's call within the lender's rules, and it is one of the least predictable parts of an HMO application.

Experience requirements

Many HMO lenders require 1 to 2 years of prior landlord experience, some specifically HMO experience for larger properties. A first time landlord buying a 6 bed HMO has a short list of lenders and pays for the privilege; the wider picture for new landlords is covered in our guide to what lenders require from a first time landlord. A common route is to run a standard single let for a year or two, then refinance onto HMO lending with experience evidenced.

What decides marginal cases

Marginal HMO cases usually turn on the valuation basis, on whether the local market supports the claimed room rents, and on condition and compliance items such as fire doors, interlinked alarms and minimum room sizes, which valuers now comment on routinely. Mixed use quirks add another layer, for example an HMO above a takeaway, where the commercial element narrows the panel further; that overlap is covered in our guide to mortgages on flats above commercial premises.