Smoke and CO alarm rules in rented homes: per storey, per room, not per floor plan

The two rules, stated exactly

For rented homes in England, there are two alarm rules, and they count different things.

• Smoke alarms: at least one on every storey containing living accommodation.
• Carbon monoxide alarms: one in any room containing a fixed combustion appliance, excluding gas cookers. This covers gas, LPG, oil and solid fuel appliances.

Both must be tested on the day a new tenancy starts.

Smoke alarms are counted per storey. CO alarms are counted per room. Neither is counted per line on a floor plan, and most mistakes come from mixing those up.

Two worked examples

A two-storey terraced house with a storage-only loft, a gas boiler in the kitchen, a gas hob, and a gas fire in the living room. Smoke alarms: two, one on each storey with living accommodation. The loft needs none. CO alarms: two, one in the kitchen because of the boiler, and one in the living room because of the gas fire. The hob adds nothing.

The same house after a loft conversion into a bedroom, with an electric hob and the boiler moved into the loft room. Smoke alarms: three, because the loft is now a storey with living accommodation. CO alarms: two, one in the loft room for the boiler and one in the living room for the gas fire. The kitchen no longer needs one.

Same building, different answers. That is why the record has to describe the property as it is, not as a template assumes it to be.

Smoke alarms: what counts as a storey

The test is whether a storey contains living accommodation. If it does, it needs at least one smoke alarm. If it does not, it does not.

Lofts

A storage-only loft is not a storey with living accommodation. A loft converted into a bedroom is. The same space can move from one side of the line to the other when its use changes, so record the use, not just the floor.

Split levels and floor plans

A floor plan may show a mezzanine, a half-landing or an annex as separate lines. What matters is the storeys that contain living accommodation, not how many rows the plan has. Count from the building, not from the drawing.

CO alarms: what counts as a fixed combustion appliance

The carbon monoxide rule is per room. Any room with a fixed combustion appliance needs an alarm. That includes appliances burning gas, LPG, oil or solid fuel: a boiler, a gas fire, an oil-fired heater, a wood burner.

The gas cooker exception

Gas cookers are excluded. A gas hob is a gas cooker for this purpose, so a kitchen with only a gas hob does not need a CO alarm on that account. A kitchen with a gas hob and a gas boiler does, because of the boiler.

The practical point: record which appliance triggered the requirement in each room. "CO alarm: kitchen" without a reason leaves the next person guessing whether it was needed.

What "tested on the day the tenancy starts" means in practice

The test happens on the day, not the week before at the inventory visit and not at the next routine inspection. If the tenancy starts on a Monday, the test record should be dated that Monday.

A test means the alarm is shown to work. Pressing the button and hearing the sounder is the test. Looking at the alarm and seeing a green light is not the same thing.

Across a portfolio, move-in days cluster, and the person doing the check-in is often the person doing the test. The record has to be simple enough to complete on a doorstep, in a few minutes, without going back to the office.

What actually goes wrong: the floor-by-floor grid, and the silent test

The first failure is the floor-by-floor grid. A checklist template lists "ground floor, first floor, second floor, loft" for every property. In a bungalow, three of the four rows are meaningless. In a property with a storage loft, the loft row invites a tick for an alarm that was never required, or an "NA" with no explanation. The grid does not match the rule, so the record does not either.

The second is the silent test. Someone ticks "alarms tested" on the check-in sheet. Did they press the button? Did it sound? Which alarm, on which storey? The tick cannot say. If a tenant later says the alarm never worked, a tick is a record that someone intended to check, not proof that the check happened.

What good evidence looks like

A test record that holds up shows five things:

1. The button pressed: the test was actually carried out.
2. The sounder audible: the alarm worked when tested.
3. A timestamp: it happened on the day the tenancy started.
4. A location: it happened at the property, not somewhere else.
5. A device bound to the property: the record belongs to this property and this check, and was captured at source rather than imported later.

A short clip captured in an app, stamped with time and location, covers all five. A photo of a ceiling covers none of the important ones. The compliance evidence guide sets out why capture at source matters.

All-electric properties, and why "not applicable" needs a reason

An all-electric property with no fixed combustion appliance needs no CO alarm. That is a correct answer, but only if the record says why.

"CO alarm: NA" with nothing else could mean the property is all-electric. It could also mean nobody looked. A checklist that lets someone tick NA with no reason cannot survive an inspection. "CO alarm: not required, no fixed combustion appliance, all-electric heating and hob" can.

The same applies to smoke alarms on a storey without living accommodation. "Loft: no alarm, storage only" is evidence. "Loft: NA" is a gap waiting to be asked about. Building the reason into the record is how our property compliance work handles it.