Leaving a Kent Coast Holiday Let Empty for Winter? How to Protect the Heating and Plumbing

If your holiday let or second home on the Kent coast is about to sit empty for the winter, the safest option for most properties is to leave the boiler on with its frost protection working and the heating set low, rather than switching everything off. Draining the whole system down is the alternative, and it is the right call for some houses, but it needs doing properly or it causes more trouble than it prevents.

We see the aftermath of getting this wrong every winter in Deal, Walmer, Kingsdown, Sandwich Bay and Broadstairs: a burst pipe that ran for a fortnight before anyone noticed, a boiler that locked out on day two and left the house unheated for three months, or a let that cannot open at Easter because the gas safety record lapsed over the winter. Almost all of it is avoidable with an hour of preparation in October.

Should you leave the heating on in an empty house?

For most holiday lets and second homes, yes. A boiler that is powered, with gas to it and the system at the right pressure, will look after itself far better than an empty, cold house will.

What “on” means matters, though. You are not trying to keep the place comfortable. You are trying to keep every pipe above freezing, including the ones in the loft, under the floor and on outside walls. In practice that usually means:

The boiler powered and in its normal mode, not switched off at the spur.
The heating on a low, steady setting, commonly somewhere around 10 to 12°C on the room thermostat, or a short daily run on the timer during cold spells.
Radiator valves left open, including in rooms nobody will use. A closed valve in the back bedroom is exactly where the pipe freezes.
Loft hatch left open if there are tanks or pipework up there, so some warmth reaches them.

The small ongoing gas cost is almost always less than the cost of a burst pipe through a ceiling, and far less than a lost letting season.

What does the frost setting on a boiler actually do?

Most modern boilers have built-in frost protection. When the water inside the boiler drops to a set low temperature, typically a few degrees above freezing, the boiler fires briefly to warm itself back up.

The important thing to understand is that frost protection on the boiler protects the boiler, not the house. It is measuring the temperature of the water in the appliance, which is usually in a kitchen or utility room. It knows nothing about the pipe running along the outside wall of an unheated garden room, or the cold feed in the loft.

Some systems have a separate frost thermostat wired to bring the whole heating system on when the room or loft gets cold. Many holiday lets on this stretch of coast do not, particularly older properties that have been extended piecemeal. If you are not sure what your system has, ask your engineer at the next service; it is a quick check.

Frost protection also only works if the boiler is able to fire. That means power, gas and pressure. A boiler that has lost pressure over the autumn, or locked out on a fault (see our Glow-worm fault code guide if yours shows a code), will sit there doing nothing while the house freezes around it. If the pressure gauge is creeping down between visits, our guide to a boiler losing pressure explains the usual causes.

Why the Kent coast catches empty homes out

Our winters are mild most of the time, which is exactly why people get caught. Whole seasons pass in Deal without a proper freeze, then an easterly comes in off the North Sea and sits over the coast for three days.

Several things about the housing here make it worse:

Seafront and near-seafront properties in Deal, Walmer and Broadstairs take the full force of that wind. Pipework on an exposed east-facing wall freezes long before the thermometer suggests it should.
Converted fishermen’s cottages and older terraces often have pipes running through unheated lean-tos, outside toilets turned into utility rooms, or suspended timber floors with a cold void underneath.
Sandwich Bay and the more isolated coastal houses can sit a long way from a neighbour who might notice water coming under the door.
Salt air. Flue terminals, external condensate pipes and outdoor taps on the coast corrode faster than they would inland. We cover this in more detail in our piece on hard water and sea air on East Kent boilers.

The condensate pipe deserves its own mention. On a condensing boiler, a frozen external condensate pipe is the single most common reason the boiler stops in a cold snap, and in an empty house nobody is there to thaw it. If yours runs outside, have it checked and, where possible, rerouted or insulated before winter. Our guide to the frozen condensate pipe shows what to look for.

A checklist before you lock up for the winter

Work through this before the last guests leave, or on your final visit of the season:

Check the boiler pressure is in the normal range on the gauge (usually between 1 and 1.5 bar when cold) and that it has not been dropping.
Set the heating to a low, steady background temperature and confirm the timer and thermostat are actually calling for heat.
Open every radiator valve and leave internal doors open so warmth circulates.
Find the stopcock and make sure it turns. A seized stopcock is useless in an emergency. Leave clear instructions for whoever holds the keys.
Isolate and drain outside taps. They are the first thing to split on a cold night.
Insulate exposed pipework in lofts, garages, under floors and on outside walls with proper pipe lagging.
Leave a key with someone local who is willing to look in after a hard frost. A burst found on day one is an inconvenience; found on day twenty it is a rebuild.
Check your home insurance terms for unoccupied properties. Many have conditions about heating or draining down when a home is left empty for a set period, and it is worth knowing them before you choose.

Should you drain down the system instead?

Draining down means emptying the water from the heating system and the cold and hot water pipework so there is nothing left to freeze. It suits properties with no reliable power over winter, homes being left for many months with nobody nearby, or houses with pipework that simply cannot be kept warm.

It is not a matter of opening a tap. A proper drain-down involves isolating the water supply, draining the heating circuit and any cylinder or tanks, and making sure nothing is left sitting in low points or traps. Refilling in spring means venting the air out, restoring pressure and checking for leaks before the boiler is relit. Anything involving the boiler itself or the gas supply must be done by a Gas Safe registered engineer. We are registered under number 2836, and our plumbing team can handle both the drain-down and the spring recommission.

Holiday lets and the gas safety record

If you let the property to paying guests, the gas safety rules for landlords apply to holiday lets too. That means an annual gas safety check on every gas appliance and a current record, often called a CP12, available for guests.

The mistake we see is the check falling due over the winter when the property is shut, and nobody noticing until the first spring booking is a week away. Book it in before you close up, or on the day you reopen, and make sure it covers the boiler, the hob and any gas fire. Our landlord gas safety certificates page explains what the check involves. It is also a sensible moment to have the boiler serviced so you go into winter knowing it is sound. Our boiler servicing and maintenance page has the detail.

Get it checked before the first frost

We are based in Deal and look after heating and plumbing across East Kent, including a good number of holiday lets and second homes along the coast. If you want your boiler serviced, your gas safety check done, or the house properly drained down before you leave, call our team on 01304 381999. A real person answers the phone, and we will give you an honest answer on when we can get to you.

If the boiler does fail while the house is empty, our boiler repairs in Deal page explains how we can help.