What is an HMO?
An HMO — a House in Multiple Occupation — is a property let to three or more tenants who form two or more separate households and who share facilities such as a kitchen or bathroom. It is the classic “house share” or multi-let, and because more people live under one roof it carries extra rules on planning, licensing and standards that a standard rental does not.
HMO rental yield (by the room)
The HMO definition, in full
The legal test has two parts that both have to be met. First, the property is the main home of three or more people. Second, those people make up two or more households who share an amenity — typically a kitchen, a bathroom or a toilet. A four-bed house let to four friends on one agreement, sharing the kitchen, is an HMO. The same house let to a single family is not, because they are one household.
This is what separates an HMO from a standard buy-to-let: it is not the building that makes it an HMO, it is who lives there and how they share. The same bricks can move in and out of HMO status depending on the tenancy.
What counts as a “household”?
A household is a single person, or members of the same family living together — a couple, a parent and child, siblings, and certain other relatives. Unrelated sharers each count as a separate household. So three unrelated professionals sharing a flat are three households; a couple plus two unrelated lodgers are three households as well. Counting households correctly is the whole game, because it decides both the planning use class and whether a licence is required.
C3, C4 and sui generis: the use classes
Planning law sorts homes into “use classes”, and HMOs sit across three of them:
HMO planning use classes
- C3 — dwellinghouse. A normal home for a single household: a family, or up to two unrelated people sharing.
- C4 — small HMO. A shared house for three to six unrelated tenants forming more than one household.
- Large HMO — sui generis. Seven or more sharers. This sits in a class of its own (“sui generis”) and always needs planning permission to create.
In most areas you can convert a C3 home into a small C4 HMO under permitted development rights — meaning no planning application is needed for the change of use. The big exception is an Article 4 Direction: where a council has made one, those permitted-development rights are removed and a C3 to C4 conversion needs full planning permission. Article 4 areas are common in student and city-centre neighbourhoods, so always check the local position before you buy to convert.
When does an HMO need a licence?
Licensing is separate from planning — a property can need both, one, or neither. There are three regimes:
The three licensing regimes
- Mandatory licensing. Required for any HMO with five or more occupants in two or more households, anywhere in England. (England removed the old “three or more storeys” condition in October 2018; Wales applies different thresholds.)
- Additional licensing. A council can extend licensing to smaller HMOs — typically three to four occupants — in a designated area.
- Selective licensing. A council can require a licence for all privately rented homes — not just HMOs — in a designated area.
A mandatory HMO licence lasts up to five years, and the holder (and any manager) must be a “fit and proper” person. Councils also set minimum room sizes for licensed HMOs in England: 6.51 sqm for one person aged over 10, 10.22 sqm for two people, and 4.64 sqm for a child under 10. We cover the detail, the application process and fines for unlicensed letting in our guide to HMO licensing.
How HMOs are financed
You can’t fund an HMO on a standard buy-to-let mortgage. HMOs use specialist BTL products, and lenders assess the deal on the number of lettable rooms and on either a bricks-and-mortar value (as a plain house) or an investment valuation based on the rental income the rooms generate. Because the risk and management are higher, HMO mortgages price above standard buy-to-let — but the room-by-room rent usually lifts the yield well above a single-family let, which is why investors take the extra rules on. See how the lending works in our guide to the HMO mortgage.
How HMO mortgages work Compare standard buy-to-letWhere Vortex Finance fits
We arrange the finance; you confirm the planning and licensing with your council. Vortex Finance is a whole-of-market property finance broker, so once you know an HMO works for your area we shop specialist lenders for the sharpest terms — whether that is an HMO mortgage, refurbishment finance to convert and licence the rooms, a bridging loan to buy at speed before refinancing onto a term product, or development finance for a larger conversion. Asking won’t affect your credit score.
Found an HMO that stacks up? Let’s fund it.
Confirm the planning and licensing locally, then come to us for the finance — whole-of-market HMO and conversion lending, with indicative terms inside 24 hours.