Private · Guide

Holiday home monitoring: frost, damp and failures all year round.

By Frigo · Updated: October 2026

A holiday home often stands empty for weeks, in winter and in summer. The risks change with the season: frost on the water pipes in winter, damp in the cellar in summer, and leaks, stale drinking water and power cuts all year. This guide shows what authorities, associations and insurers say about this and which duties insurance terms typically contain. Pick your country and you see only what the bodies there say.

In short

Winter: warmth is considered the most effective frost protection for water pipes. If you do not heat continuously, shut off the water and drain the pipes.
Summer: warm, humid air condenses on cool cellar walls. The German Environment Agency and the Swiss BAG advise against airing cellars during the day in summer.
Water while you are away: many policy terms require buildings not in use to be shut off or checked, in some cases at any time of year. Your policy is what counts.
Austria: some water damage policy terms contain a 72-hour rule for shutting off the water supply.
Switzerland: according to AXA, frost damage to pipes is not covered by the cantonal building insurance but by optional building water insurance.
When you return: let drinking water that has stood in the pipes for a long time run until it comes out of the tap cool and at a steady temperature.
Frigo during a power cut: the connectivity unit keeps running for about four hours on its built-in battery.

Who this guide is for

Owners of holiday flats, chalets, second homes, weekend houses and hunting lodges
Landlords whose properties stand empty between bookings
Anyone who is rarely on site, whatever the season

The year at a glance

When	Main risk	What the sources say
Winter	Frost on water pipes, heating failure	Heat, or shut off and drain (GDV, AXA, Vienna Water)
Summer and transitional seasons	Damp and mould, especially in the cellar	Do not air the cellar during the day, keep an eye on humidity (UBA, BAG)
All year	Leaks, stale drinking water	Shut off the water while away, let it run when you return (policy terms, UBA, water associations)
All year	Power cuts, fridges and freezers	See the guides on fridges and chest freezers

Winter: frost and heating

When water pipes are at risk

Vienna Water warns that pipes can burst when temperatures stay below 0 °C for a longer period. Pipes outdoors, water meters, outlets in cellars, garages or gardens and pipes in weekend houses are particularly at risk. The German Insurance Association (GDV) lists holiday flats, unheated rooms and rooms with leaky windows among the areas at risk.

The damage often shows later. According to a guide by AXA Switzerland, burst pipes in empty holiday homes often become visible only when the ice thaws and water escapes.

Heat, shut off, drain

The sources essentially name two routes: heat the house continuously, or shut off and drain the water system. None of the sources checked gives a generally valid minimum temperature for an unoccupied holiday home.

Measure	What the sources say
Heating	According to the GDV, warmth is the most effective frost protection. Rarely used rooms with water pipes should be heated too.
Frost setting	According to the GDV it protects only the radiator, not pipes laid further away. In prolonged frost never close the valve completely.
Shut off and drain	Close the main valve and open the taps so the remaining water runs out (AXA). Drain outdoor pipes early and shut off outdoor taps (GDV).
Leaving taps running	According to Vienna Water this does not prevent freezing and can cause drain pipes to ice up.
Pipe frozen	Do not thaw it yourself, close the main valve and contact your insurer (AXA).

How your system is drained completely depends on the installation. If in doubt, clarify this with a plumber.

Would you notice if the heating in your holiday home failed or the cellar turned damp?

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Insurance: what policy terms often contain

Insurance terms often contain duties you must meet before any damage occurs, known as obligations or duties of care. Some apply only in the cold season, others all year. If you breach them, the insurer may cancel the policy or reduce or refuse payment. Which duties apply to you is set out only in your own policy. The following examples are not legal advice. Your policy is what counts, ask your insurer.

Austria: water damage policy terms and Vienna Water

What the bodies say

Example policy terms: the general terms for water damage insurance (AWB 2024) of Oberösterreichische Versicherung state: if a building is left by all persons for more than 72 hours, all water supply lines must be shut off and suitable measures against frost damage taken. The rule is not limited to winter. Under § 6 of the Insurance Contract Act (VersVG), a breach can release the insurer from its obligation to pay. Your AWB may be worded differently.
Vienna Water: drain pipes in weekend houses carefully, protect exposed outlets, close cellar windows and insulate pipes. Leave the taps open on drained garden pipes so the seals do not freeze.

We did not find a specific recommendation on holiday homes from the Austrian Insurance Association (VVO) for this article.

Germany: GDV model terms and Haus & Grund

What the bodies say

GDV model terms (VGB 2022): buildings or parts of buildings that are not in use must be checked sufficiently often at all times of year, and water-carrying systems shut off, drained and kept drained (A 20.1.2). In the cold season all buildings and parts of buildings must be heated and this checked sufficiently often, or alternatively shut off and drained (A 20.1.3).
Increase in risk: under the same model terms, if the building or most of it is no longer used, this can be an increase in risk that must be reported (A 21.1.2). Whether this applies to your holiday home is something to clarify with your insurer.
Non-binding: the GDV publishes these terms as non-binding models. Insurers may deviate. The model terms give no figure for “sufficiently often”.
Haus & Grund Ostwestfalen-Lippe: the homeowners' association quotes inspection intervals from the Institute for Loss Prevention and Loss Research (IFS) as a guide: in light frost (−2 to −5 °C) every three days, in moderate frost (−5 to −10 °C) every two days, in severe frost (below −10 °C) daily. This is not a regulation.

Switzerland: building water insurance and the BAG

What the bodies say

Who pays: according to AXA Switzerland, the cantonal building insurance does not pay for frost damage because frost is not a natural hazard event. Optional building water insurance is responsible. Check whether your holiday home is insured this way.
Duties of care: according to AXA, even well-insured owners must meet duties of care and obligations. Which ones apply is set out in the terms of your policy.
Heating: AXA advises never to switch the heating off completely, even in temporarily unoccupied properties, and to keep it running at least at level 1. If the property stays unused for longer, pipes, fittings and appliances should be drained.
BAG: do not leave individual rooms completely unheated, except cellars and attics built as cold rooms.

The advice on heating and draining consists of recommendations, not regulations.

Summer and transitional seasons: damp and mould

Cool walls and little ventilation encourage damp, and this affects rarely used rooms all year. According to the BAG, mould depends less on the humidity in the room than on the moisture at material surfaces. Room humidity is still a useful indicator. The authorities give different values:

Body	Guide
German Environment Agency (UBA)	Relative humidity between 40 and 60 per cent. If it stays above 60 per cent for days and weeks, this can encourage mould growth.
Swiss Federal Office of Public Health (BAG)	Rule of thumb 30 to 50 per cent, on very cold days no more than 40 per cent. In poorly insulated older buildings, around 50 per cent can already cause condensation in autumn and winter.

These values refer to living spaces. The authorities give no separate values for an unoccupied holiday home. The minimum temperatures of 16 to 18 °C named by the UBA apply to homes in use. The UBA recommends keeping an eye on room humidity with a hygrometer. The BAG points out that a mould risk cannot easily be derived from such measurements.

Cellars in summer: do not air during the day

According to the BAG, summer is an unfavourable season for cellars. If warm, humid summer air gets into a cool cellar during airing, it cools down, the moisture condenses on the walls and the risk of mould rises. The UBA describes the same effect for the often cold outer walls of cellars, especially in older buildings.

UBA: do not air cellars during the day in summer, but preferably at night or in the cool early morning.
BAG: keep cellar windows and doors closed most of the time in summer without giving up airing altogether, and use cooler periods for it. For cellars that are too damp, the BAG names dehumidifiers among other measures, in summer for example at night on a timer.

For a holiday home, this means: if you open all the cellar windows during the day on a summer visit and then leave, you may raise the humidity in the cellar rather than lower it. A sensor in the cellar shows the trend even when nobody is on site. If you store wine there, see also the guide to wine cellar climate.

Water: leaks and absence

Shut off the water when nobody is there

A leaking hose or a faulty fitting can let water escape unnoticed for a long time, in summer too. Several sources therefore advise shutting off the water while you are away. Whether this is a duty under your policy is set out in its terms.

GDV model terms (VGB 2022): for buildings not in use, water-carrying systems must be shut off, drained and kept drained at all times of year (A 20.1.2), provided your policy contains this rule.
Stiftung Warentest: during a longer absence, turn off the main tap and inform your insurer, otherwise the insurer could refuse to cover damage.
Example AWB 2024 (Oberösterreichische Versicherung): if a building is left by all persons for more than 72 hours, all water supply lines must be shut off.
AXA Switzerland: in the event of pipe damage, close the main valve and contact your insurer. If a property stays unused for longer, drain pipes, fittings and appliances.

Where the main valve is and whether it closes easily is best checked during a visit, not when damage has already occurred.

When you return: let the drinking water run

Water that has stood in the pipes for a long time is called stagnant water. It is no longer fresh: substances from pipes and fittings can pass into it, and microorganisms can multiply. The UBA explicitly names holiday flats as a typical case.

UBA: do not use water that has stood in the pipes for more than about four hours for drinking or cooking, but let it run until it comes out of the tap cooler. If pipes are not in use, flush them regularly or separate them from the rest of the system. As a guide: from three days, open the taps so that the water is fully exchanged; for more than four weeks, shut off the affected pipes before leaving and flush them when putting them back into use. Do not use hot water from the tap for drinking or cooking.
trinkwasserinfo.at (a project of the Austrian Ministry of Social Affairs and Health, ÖVGW and AGES): after a holiday, flush the household installation and let the water run until its temperature no longer changes.
City of Vienna: if sanitary installations have not been used for a longer time, for example during a holiday, let standing tap water run off. In buildings with lead pipes, do not use stagnant water for food, coffee, tea or baby formula.
SVGW (Swiss Gas and Water Industry Association): drink and cook only with fresh cold water, and let the water run until it is consistently cool. On returning from holiday, longer flushing is advisable.

According to the UBA, you can use the water you let run for cleaning or watering plants. Questions about your own installation are best clarified with your water supplier or a plumber.

Fridge, freezer and power cuts

If a fridge or chest freezer is running in the holiday home, nobody notices a fault or power cut until someone opens the door. How cold a fridge should be is covered in the guide how cold should your fridge be?. What applies to frozen food during a power cut is explained in the guide to chest freezer power outages. A sensor in the appliance measures the air in the appliance, not the temperature of the food.

Where checks on site leave gaps

Nobody on site. Days or weeks often pass between two visits.
The heating fails. A fault or an empty fuel supply is noticed only when someone checks.
Power cut. Depending on the system, the heating, fridge and freezer may stop as well. For the heating, clarify this with your heating engineer.
Window open or leaky. A tilted window cools a room down in winter and lets humid air into the cellar in summer.
Water on the floor. A small leak goes unnoticed until the next visit.
Humidity rises slowly. A visit is a snapshot and shows no history.

What a sensor adds

A sensor measures temperature and relative humidity around the clock, in winter and in summer. You set an upper and a lower limit per sensor. If a value leaves this range, Frigo alerts all the people you have named by app and email, with SMS as an additional option. Every deviation is written with start, end and duration to a continuous, time-stamped record. For water on the floor, for example by the boiler, the washing machine or under the sink, Frigo offers dedicated leak sensors. Where it makes sense, a door or opening contact can also be used.

The sensors stick on, with no drilling and no cables. One connectivity unit per site plugs into a power socket and has its own mobile connection, so no Wi-Fi is needed in the holiday home. If a sensor or the connectivity unit stops sending data, Frigo alerts the named people.

Important: Frigo measures the air at the sensor's location, not the temperature inside the pipe, the wall or the food. It does not heat anything, does not control any heating, does not shut off any water and does not prevent damage, it alerts you earlier. A sensor does not replace any duty under your insurance contract and says nothing about whether your insurer will pay in the event of a claim.

If power fails, the connectivity unit keeps running on its built-in battery for about four hours. During that time Frigo keeps measuring and alerts you when a value leaves your limit, as long as the mobile network is available. Once the battery is empty, Frigo reports that the connectivity unit has stopped sending data. The sensors do not store readings, so there is no data for that period. New readings arrive once the connectivity unit has power again. If only the heating fails and the power stays on, this time limit does not apply.

How the system is built is explained under How does Frigo work?.

Four things to set per room

the sensor location, for example the room with water pipes that cools down fastest, the cellar or the spot next to the boiler and washing machine
the temperature and humidity limits at which an alert is sent, depending on the season
who is notified, including at night and at weekends
who has a key, checks on site and what to do then

Frequently asked questions

Is the frost setting on the radiator enough?

Not for the pipes. According to the GDV, the frost setting protects only the radiator, not pipes laid further away. In prolonged frost the valve should never be closed completely. AXA Switzerland advises keeping the heating in unoccupied properties at least at level 1.

Should I shut off the water in my holiday home when I am not there?

Many sources advise it, and some policy terms require it. The GDV model terms provide for water-carrying systems in buildings not in use to be shut off at all times of year, some Austrian water damage terms from an absence of 72 hours. In winter, draining is added if you do not heat continuously. Your policy is what counts.

Should I air the cellar in summer?

Not during the day. Warm, humid summer air cools down in the cellar and the moisture condenses on the walls. The German Environment Agency advises airing cellars in summer preferably at night or in the cool early morning. The BAG recommends keeping cellar windows and doors closed most of the time in summer and using cooler periods for airing.

Can I drink tap water straight away after a longer absence?

Let it run first. The German Environment Agency advises not to use water that has stood in the pipes for more than about four hours for drinking or cooking and to let it run until it comes out of the tap cooler. The SVGW considers longer flushing advisable on returning from holiday. Your water supplier can help with questions about your own installation.

Does Frigo work during a power cut?

Yes, for a limited time. The connectivity unit has a built-in battery and keeps running for about four hours during a power cut. During that time Frigo keeps measuring and alerts you when a value leaves your limit, as long as the mobile network is available. Once the battery is empty, Frigo reports that the connectivity unit has stopped sending data. The sensors do not store readings, so there is no data for that period. New readings arrive once the connectivity unit has power again.

Does a sensor secure my insurance cover?

No. A sensor does not replace any duty under your insurance contract, and Frigo makes no statement on whether your insurer will pay or change your premium. Frigo measures the air at the sensor's location and reports deviations so that someone can check in time.

Sources

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This article is guidance, not legal, insurance or health advice. It reproduces recommendations from authorities, associations and insurers as well as examples from policy terms, which can differ. What counts are your policy, your insurer, the applicable regulations, your water supplier and the information from the manufacturers of your systems. Frigo measures temperature and humidity at the sensor's location, does not heat anything, does not shut off any water and does not prevent damage. Alerts require a working connection. During a power cut the connectivity unit keeps running on its built-in battery for about four hours, after that Frigo reports that the connectivity unit has stopped sending data. Sources as of: October 2026.