Protecting a property between bookings
The most expensive thing that happens to a short let happens when nobody is in it. This is the least glamorous technology in hospitality and comfortably the highest return.
The most expensive thing that happens to a short-let property usually happens when nobody is in it. A pipe splits in February. A washing machine hose fails on a Tuesday and runs for four days. The heating stops in a cold snap. A guest leaves a window open and the property sits at four degrees for a fortnight.
None of these are guest problems, none are detected by anything a booking platform provides, and all of them are cheap to catch. This is the least glamorous category in short-let technology and comfortably the highest return.
Water: the risk with the worst ratio
Water damage is the most common expensive incident in unoccupied property, and the cost of prevention is trivial by comparison. A leak that runs for days destroys flooring, ceilings and plaster, and in an apartment it damages the flats below, which turns a repair into a liability claim.
Where to put sensors
Under every sink, behind the washing machine and dishwasher, beside the boiler or hot water cylinder, in any airing cupboard with pipework, and beneath a bathroom if it sits above a habitable room. In a flat, add the point where pipes enter, because a supply-side failure is the worst case.
Detection is good; shutoff is better
A sensor that notifies you is useful only if someone can attend. If you are two hours away or abroad, a notification tells you the size of the problem rather than reducing it. A motorised valve on the incoming main, triggered by the sensors, turns a flood into a puddle.
Where a valve is fitted, exercise it monthly — a valve that has not moved in two years frequently will not. Most systems can be set to cycle themselves, and this should be enabled.
Flow monitoring for the slow leak
Spot sensors catch leaks where they are placed. A whole-property flow meter catches the ones that are not: a running toilet, a dripping outside tap, a slow failure inside a wall. Continuous flow with no pause, in a property you know to be empty, is unambiguous.
Freezing: the seasonal catastrophe
A frozen pipe that splits does not leak while frozen. It leaks when it thaws, which is typically when nobody is expecting it, and the resulting damage is among the most severe in domestic property.
Two protections, and both are cheap. Temperature sensing with a low alert, in the coldest parts of the property — a loft, an unheated utility, an outbuilding, a room above a garage. And frost protection heating, meaning the heating never allows the property to fall below a set floor even when nominally off between bookings.
The economics are not close. Holding an empty property at around ten degrees costs a modest amount over a winter. A split pipe costs thousands and takes the property out of service for weeks in the middle of a booked season.
Never switch heating fully off in an empty property in winter. Frost protection at a low setting is the correct configuration, not off. This applies even where a property is empty for a single cold week, and it applies especially to properties with pipework in lofts or unheated spaces. Check your insurance policy as well — many policies contain specific conditions about unoccupied periods, minimum temperatures and water isolation, and a claim can be refused for non-compliance.
Insurance conditions worth reading
This deserves its own attention because it catches hosts out. Policies covering let property frequently include conditions on unoccupancy: a maximum number of consecutive days unoccupied before cover changes, a requirement to isolate water or maintain a minimum temperature over winter, and requirements about alarm setting.
Two practical implications. Find the actual wording rather than assuming, since “unoccupied” may be defined more strictly than you expect. And where the policy requires a minimum temperature or water isolation, monitoring gives you evidence you complied — which is worth having if you ever need to claim.
Heating between bookings
The economically correct approach is a setback rather than off, with a pre-heat before arrival.
Hold the property at a frost-protection floor when empty. Bring it to comfort temperature a few hours before check-in, working backwards from how long your property actually takes rather than guessing. Return to setback after check-out, triggered by the door contact and the booking rather than by a fixed time, so an early departure does not heat an empty house all afternoon.
The guest experience benefit is real too. Arriving at a warm property after a long journey is one of the things guests consistently mention, and it costs almost nothing when it is scheduled rather than continuous.
The other empty-property risks
Damp and mould. An unheated, unventilated property in winter grows mould, particularly in bathrooms and on cold external walls. Humidity monitoring with a threshold alert catches it, and intermittent ventilation or a low heating floor prevents it. This is a common and expensive discovery after a long off-season.
Power failure. A power cut in an empty property means no heating, no frost protection and no monitoring. A hub on a small uninterruptible supply will at least tell you it happened, and its own silence tells you something is wrong.
Fridge and freezer failure. If you leave anything in them, a temperature sensor is worth it. Better, empty and switch them off between bookings.
Break-in. Contact sensors on doors and windows, and a visible camera at the entrance. Empty properties in obvious holiday areas are targeted seasonally.
Post and deliveries piling up. A visible signal that a property is empty. A letterbox sensor is a small thing that prompts someone to clear it.
Who responds, which is the whole system
Every alert in this article is worthless without a person who can attend. This is the part hosts most often leave undefined.
Have a named local contact — a cleaner, a neighbour, a co-host, a management company — who receives alerts alongside you and can get in. Make sure they can actually get in, which means a key safe or a credential of their own, tested. And agree in advance what they are authorised to do: turn the water off, call a plumber, or wait for instruction.
Then test it. Trigger a leak alert deliberately once a year and confirm the whole chain works, including that the local contact received it and knew what to do.
A configuration that pays for itself
- Leak sensors at every water point, and a motorised mains valve if the property is not quickly reachable.
- Temperature sensors in the coldest spaces, with a low-temperature alert.
- Frost protection heating that never allows the property below a floor, with pre-heat before arrival.
- Humidity monitoring in bathrooms and any room with mould history.
- A hub on a UPS, processing locally, with an alert if any sensor goes quiet for a day.
- A named local contact who receives alerts, can get in, and knows what they are authorised to do.
- An annual test of the whole chain.
The total cost is modest and the first prevented incident pays for all of it several times over. Of everything in this category, this is the part we would install before anything guest-facing.