Fan, portable AC or split unit? What cooling costs per summer, what the EU label really says, which refrigerants are on the way out and when shading is enough.
Illustration: AI-generated
39.7 degrees at Hohe Warte in Vienna, recorded at the end of June — the old June record of 36.1 degrees from 1950 was beaten by a full 3.6 degrees. According to the heat report from GeoSphere Austria, the national weather service, 157 of 277 weather stations set new June records in 2026, and below 800 metres altitude the country strung together ten to 14 heat days in a row, depending on the region. On the night of 29 June, the temperature at the Jubiläumswarte never dropped below 27.3 degrees — the warmest night ever measured in Austria (GeoSphere Austria, heat report of 1 July 2026). Anyone who spent those weeks in a Viennese attic flat or an unshaded Altbau in Graz has long since googled the question: buy an air conditioner, yes or no? And if so, which one? The answer depends less on how badly you feel the heat than on three sober factors: electricity consumption, purchase price and — often overlooked — the refrigerant inside the unit.
What running one actually costs
What a kilowatt hour costs is shown by the regulator E-Control's price monitor: an average household using 3,500 kilowatt hours a year pays its regional incumbent supplier between €891 (Tiwag) and €1,218 (Energie Klagenfurt), grid charges, taxes and levies included (E-Control, price monitor of 1 October 2026). That works out at roughly 25 to 35 cents per kilowatt hour on average — the range used in the examples below. Why it is worth checking your own tariff is something our analysis of electricity prices in Austria in 2026 makes clear.
The differences in running costs start with physics: a fan does not cool the air, it only moves it. The breeze makes sweat evaporate faster, and that feels cooler. How much electricity it needs is printed on the rating plate. A worked example with a 50-watt unit running eight hours a day for 90 days: that is 36 kilowatt hours, or roughly €9 to €13 for the whole summer.
The portable monobloc air conditioner — the DIY-store classic with its exhaust hose wedged into a tilted window — is a different story altogether. It does actually cool, but at a disadvantage: warm air streams back in through the window gap, so the unit works against itself. A worked example with a power draw of 1,000 watts — here too, the rating plate is what counts: four hours a day on 60 summer days comes to 240 kilowatt hours, or roughly €60 to €84. Anyone cooling eight hours a day in a summer like this one doubles that to 480 kilowatt hours and roughly €120 to €168 — for a single room.
The permanently installed split system with an outdoor unit is the more efficient design, and the EU energy label shows the difference if you know how to read it. Split units are rated by their seasonal energy efficiency ratio, SEER: it states how many kilowatt hours of cooling the unit delivers over a cooling season per kilowatt hour of electricity. Class A+++ starts at a SEER of 8.50. Portable single-duct units have a scale of their own that only rates efficiency under standard rated conditions; there, a value of 4.10 is enough for A+++ (Delegated Regulation (EU) No 626/2011, Annex II). So the same letters do not mean the same thing for both designs — when comparing, look at the number, not the plus signs.
The maths over several summers
When it comes to the purchase price, the picture flips. A portable unit is simply plugged in; a split system has to be mounted and commissioned by a specialist firm, and it needs maintenance. What that costs in any given case depends on the unit, the length of the pipe run and where it is mounted — a written quote listing every item is the only reliable figure here.
Add up purchase and running costs, and the monobloc usually still comes out as the cheaper overall solution over the first few years: the split system's premium takes many years to claw back through electricity savings alone — its arguments are efficiency, quiet running and lifespan, not quick payback. And all of this presupposes you are allowed to install one in the first place; that is exactly where things often fail in rented flats, more on which in a moment. For everyone else, a simple rule of thumb applies: the cheaper the appliance is to buy, the more expensive it becomes to run.
That this calculation now concerns ever more households is shown by Statistics Austria's energy microcensus. The number of households reporting an installed air conditioner almost doubled within four years:
| Survey | Households with air conditioning | Share of all main residences |
|---|---|---|
| 2019/2020 | 210,102 | 5.3% |
| 2021/2022 | 314,572 | 7.8% |
| 2023/2024 | 414,538 | 10.0% |
Source: Statistics Austria, household energy use, table "Renovation measures and air conditioners 2018–2024", created 14 May 2025. Share calculated by us from the number of main-residence dwellings in the same survey.
Cooling is thus becoming a significant line item in household electricity — and belongs in any assessment of where the biggest electricity-saving levers in the home lie.
Refrigerants: the overlooked climate problem
Fighting the heat with an appliance that fuels global warming is a consistency problem — and that is precisely what lurks inside many air conditioners. Under the EU F-gas Regulation, the currently widespread refrigerant R32 has a global warming potential (GWP) of 675 (Regulation (EU) 2024/573, Annex I): one kilogram, if it escapes, has the climate impact of 675 kilograms of CO₂. The older R410A sits at 2,088. The alternative has long existed: propane, known in refrigeration engineering as R290, is a natural refrigerant with a GWP of 3 (German Environment Agency, 14 March 2018).
The EU is tightening the screws here. Under the F-gas Regulation (EU) 2024/573, plug-in room air conditioners and monobloc units up to 12 kilowatts may no longer be newly placed on the market from 1 January 2027 if they contain fluorinated gases with a GWP of 150 or more — which rules out R32 for this class of appliance. For small mono-split units with a charge below three kilograms, the cut-off has been a GWP of 750 since 1 January 2025, which affects R410A. For air-to-air split units up to 12 kilowatts, the 150 limit applies from 1 January 2029 — at which point R32 is finished there too. Exceptions apply only where safety rules at the installation site require a different refrigerant (Regulation (EU) 2024/573, Annex IV). Units already installed may keep running. Anyone buying now should nonetheless ask specifically for R290 units: they are already on the market and spare you an appliance that is regulatorily obsolete the day you buy it.
Buying an air conditioner with a classic F-gas refrigerant in 2026 means cooling yourself against the heat with a substance that makes it worse in the long run.
Tenancy law and safety: what you need to know
The legal side first: a portable unit that is simply plugged in with its hose hung out of the window does not alter the flat. A permanently mounted split system with an outdoor unit and a hole through the wall, by contrast, is an alteration to the rented property that must be notified to the landlord beforehand. For flats fully covered by the Tenancy Act (Mietrechtsgesetz), consent is deemed granted if the landlord does not refuse within two months of receiving the notice (Section 9 Tenancy Act). For the outdoor unit, the owners' association and the province's building regulations may also have a say — ask before ordering, not after.
One safety warning deserves to be taken seriously, from Vienna's chimney sweeps' guild: in flats with a gas boiler, it advises against portable air conditioners. The unit blows air outside and thereby changes the pressure conditions in the flat; if the boiler's exhaust cannot escape as a result, odourless carbon monoxide becomes life-threatening within minutes. The plumbers' guild advises always ventilating when the boiler or instantaneous water heater is running in summer, and having both appliances serviced every year (ORF Vienna, 19 June 2022). Anyone who still wants to run a portable unit should get advice from their chimney sweep first. Then there are the everyday rules: match the unit's capacity to the room size before buying, clean the filters regularly, take maintenance seriously, because bacteria and mould settle in neglected appliances.
Cooling without an appliance: shading beats technology
The most effective cooling is the heat that never gets in. Lower Austria's provincial energy advice service puts it unequivocally: external sun protection keeps out up to 80 per cent of solar radiation and is around three times as effective as interior shading such as blinds or curtains, because the heat never gets through the window in the first place (Energy and Environment Agency of Lower Austria, guide to summer comfort at home, June 2025). In concrete terms, for the summer that means:
- Fit roller shutters, external venetian blinds or awnings on the outside wherever it is structurally and legally possible — in a rented flat, ask the landlord if in doubt; in a jointly owned building, consult the other owners
- Keep windows and shading closed during the day, especially on the south and west sides
- Cross-ventilate at night and in the early morning, when the outdoor air is cooler than the indoor air — although in June 2026 it was admittedly sometimes too warm even for that
- Switch off internal heat sources: the oven, old halogen lamps and appliances running around the clock all add to the heat
The principle behind it is the same as in winter, only in reverse: the building envelope and your own ventilation habits determine how much technology you need in the first place — anyone familiar with the logic will recognise it in our guide to heating and ventilating properly.
That leaves the honest bottom line. For most flats in Austria, the combination of rigorous shading, night-time ventilation and a fan is enough — with electricity costs that stay in the single or low double digits of euros over an entire summer. For anyone living in an attic flat, coping with health conditions or getting small children through tropical nights, an efficient split system with R290 refrigerant is the cleanest technical solution — expensive to buy, but frugal to run. The portable monobloc unit, the one that sells fastest in heatwaves, is of all things the least convincing option: loud, inefficient and, over time, the most expensive way to cool a room. June 2026 has shown that the question is no longer whether such summers are coming. Only how cleverly we prepare for them.
