How Much Does Air Conditioning Really Cost to Run? Calculating Your Actual Bill in 2026
L'équipe Proclimo
27 Sep 2026 - 07 min read
"So how much does it actually use?" It's the question that always comes up, right after the price on the quote. And it's also the one that attracts the most far-fetched answers: between the neighbour who swears his AC costs him €15 per summer and the article announcing "+40% on your bill", the gap is so wide that no rational decision is possible. Yet estimating the consumption of an air conditioner or an air-to-air heat pump comes down to a simple, three-variable calculation that any homeowner can do in ten minutes. Here is the method, the real-world figures for 2026, and above all the settings that can double or halve the final figure.
The initial misunderstanding: output power ≠ consumption
The most common confusion comes from the numbers printed on product datasheets. A "3.5 kW" wall-mounted split unit does not consume 3.5 kW.
That figure refers to the cooling capacity delivered, in other words the amount of heat the machine is able to extract from your room. The power drawn from the electricity grid is far lower: that is the whole principle of a heat pump, which moves heat rather than producing it.
The ratio between the two is called the coefficient of performance. Two official indicators, defined by the European ecodesign regulation, must appear on the energy label:
| Indicator | Meaning | Typical values in 2026 |
|---|---|---|
| SEER | Seasonal efficiency in cooling mode | 6.0 to 9.5 |
| SCOP | Seasonal efficiency in heating mode | 3.8 to 5.2 |
A SEER of 7 means that, averaged over an entire cooling season, the unit delivers 7 kWh of cooling for every 1 kWh of electricity consumed. It is a weighted average based on a standardised climate profile, not a performance figure at any given moment — and that is precisely what makes it usable for an annual calculation.
Be careful not to confuse SEER (seasonal) with EER (at full load, at one specific operating point). The latter is always more flattering and has no predictive value for your bill.
The formula, in three variables
Annual consumption in kWh is calculated as follows:
Consumption (kWh) = Annual cooling demand (kWh) ÷ SEER
That still leaves the cooling demand to be estimated, which depends on the power actually called for and the number of operating hours. In practice, a more direct version is used:
Consumption (kWh) = Cooling capacity (kW) × Hours of use × Average load factor ÷ SEER
The average load factor is the parameter everyone forgets. An inverter air conditioner almost never runs at full power: it modulates. Over a typical French season, the average load factor sits between 0.4 and 0.6 — in other words, the machine delivers on average 40 to 60% of its rated capacity during its running hours.
A concrete example: a 30 m² living room in the Lyon region
- Wall-mounted split unit of 3.5 kW cooling capacity, SEER = 7.0
- Use: 500 hours over the season (roughly 5 h/day for 100 days from June to September)
- Average load factor: 0.5
Calculation: 3.5 × 500 × 0.5 ÷ 7.0 = 125 kWh over the season.
At the regulated electricity tariff, which sits at around €0.20/kWh incl. tax in 2026 for the base option (the exact rate depends on your supplier and your subscribed power level — the national energy ombudsman's comparison tool lets you check), that works out to roughly €25 for the summer.
Yes, €25. The figure surprises people every time.
Why some bills still spiral
If the theoretical calculation gives such modest amounts, why are there so many accounts of hefty bills? Because four factors, all usage-related, can multiply that result by five or more.
1. The number of hours, badly underestimated
500 hours reflects occasional comfort use. A household working from home, in an exposed house in the south of France, leaving the AC running from 9 a.m. to 11 p.m. from late May to mid-September, easily reaches 1,400 to 1,600 hours. The same calculation then gives 350 to 400 kWh, or €70 to €80 per air conditioner. And if the house has three indoor units on a multi-split system, you're approaching €200.
2. A setpoint that's too low
This is the most powerful and most poorly understood lever. Every degree lower on the setpoint increases consumption by around 7%, a figure cited by both ADEME and European energy-saving recommendations. Going from 26 °C to 21 °C is therefore not "a little more": it's roughly +40% consumption, for comfort that is often worse (thermal shock, dried-out air).
ADEME recommends a setpoint of 26 °C during hot spells, with a maximum gap of 5 to 7 °C compared with outdoor temperature. Regulation, for its part, has since the decree of 23 July 2022 prohibited cooling a space below 26 °C in buildings open to the public — a useful benchmark even at home.
An indoor thermometer hygrometer placed in the main room is worth more than the air conditioner's own sensor, which is often mounted high up and reads a temperature above what occupants actually feel.
3. Poor sizing
An oversized unit runs in short cycles: it reaches the setpoint too quickly, stops, restarts. And start-ups are the least efficient moments. A 5 kW split unit in a 12 m² bedroom will consume more than a correctly sized 2.5 kW model, while dehumidifying less effectively (the cycles are too short for condensation to build up).
The reference sizing figure is around 100 W per m² for a properly insulated home, to be adjusted according to orientation, glazed surface area, floor level and the building's thermal mass. Under the roof with large south-facing windows, you go up to 130–150 W/m².
4. Fouling and dirt
A clogged filter, an outdoor heat exchanger blocked by poplar fluff or leaves: the machine has to work harder, condensing pressure rises, and the real-world COP collapses. It is commonly estimated that neglected maintenance costs 10 to 25% of efficiency. Cleaning the filters every two to four weeks during the season, with lukewarm water, covers the essentials; an air conditioner foam cleaner applied once or twice a year to the indoor heat exchanger usefully complements the job between refrigeration engineer visits.
And in heating mode? The real bill driver
This is where the amounts change scale. In winter, running times are far longer, temperature differences greater, and the SCOP lower than the SEER.
Let's take the same properly insulated 100 m² house, with an annual heating demand of around 9,000 kWh:
| System | Efficiency / SCOP | Electricity or gas consumption | Estimated annual cost |
|---|---|---|---|
| Air-to-air heat pump, SCOP 4.3 | 4.3 | 2,093 kWh elec. | ≈ €420 |
| Electric convector heaters | 1.0 | 9,000 kWh elec. | ≈ €1,800 |
| Condensing gas boiler | 0.95 | 9,470 kWh gas | ≈ €1,050 |
These amounts are indicative, based on electricity at €0.20/kWh and gas at around €0.11/kWh incl. tax and standing charge — values that shift with every tariff revision.
The gap with direct electric heating is huge: that is the real economic argument for reversible air conditioning, and indeed the logic behind aligning VAT at 5.5% on air-to-air heat pumps in July 2026. Summer cooling, meanwhile, remains a comfort use whose marginal cost is low.
The decisive comparison is therefore not "with or without AC", but "air-to-air heat pump versus your current heating system". A household heated by convector heaters that installs a reversible unit can cut its heating bill by half or more, with summer cooling largely absorbed by those savings.
Measure instead of estimating
All the calculations above remain ballpark figures. If you want the real number for your installation, you have to measure it.
Three approaches, in order of increasing accuracy:
- Tracking your Linky meter. Your supplier's customer portal, or the Enedis "consumption tracking" service, lets you display the load curve in half-hour increments. Compare a day without AC against a day with it, all other things being equal. Crude but free.
- A plug-in energy meter. For a portable unit or a console powered from a socket, a plug-in power meter connected in line gives you cumulative kWh directly. Very decent accuracy, negligible cost.
- A clamp meter on the dedicated circuit. A fixed split unit is wired to a dedicated line at the consumer unit; a measurement module on the breaker or a digital clamp meter lets you track the circuit's actual consumption. This is the most reliable method for a multi-split system.
Some manufacturers (Daikin, Mitsubishi Electric, Atlantic) also offer energy monitoring in their mobile app, via a Wi-Fi module. The data is estimated, not measured by a certified meter, but it remains useful for comparing two settings against each other.
The settings that genuinely cut the bill
Once the diagnosis is made, here are the levers ranked by effectiveness-to-effort ratio.
- Raise the setpoint to 26 °C and accept a bit of air movement. A simple quiet ceiling fan, or a tower fan in the living area, gains you 2 to 3 °C of perceived temperature for a consumption of 30 to 60 W — nothing like the cost of lowering the setpoint by the same amount.
- Close shutters and blinds during the day. An unshaded south-facing window lets in several hundred watts per m². External solar shading is far more effective than an interior curtain.
- Program it rather than letting it run. Starting up 30 minutes before you get home is enough; keeping a room at 24 °C all day in an empty home is the most common form of waste.
- Take advantage of the new summer off-peak windows, now shifted to the middle of the day for some subscribers. Pre-cooling the home during those hours can reduce the cost without changing consumption.
- Clean the filters every two weeks at the height of the season. The most cost-effective action on the list.
- Check how airtight your home is. An AC running with a window ajar loses most of its effect. A window sealing strip kit will fix in one afternoon a flaw the unit would otherwise be compensating for all season.
Key takeaways
Under reasonable comfort use, air conditioning costs between €20 and €80 per season per indoor unit in a properly sized French home. Spectacular bills almost always come from a combination of factors: several units, near-continuous use, a setpoint at 20 °C and forgotten maintenance.
The calculation is within your reach: cooling capacity × hours × load factor ÷ SEER, then multiply by the price of your kWh. Do it before signing a quote, and do it again at the end of the season using your meter data. The gap between the two will tell you exactly where your room for improvement lies.
Useful sources and references: ADEME (guides on staying cool without breaking the bank and setpoint recommendations), European Regulation 206/2012 on the ecodesign of air conditioners (SEER/SCOP definitions), Decree no. 2022-1034 of 22 July 2022 on heating and cooling temperatures, Commission de régulation de l'énergie (regulated sales tariffs), médiateur national de l'énergie (offer comparison tool), Enedis (Linky consumption tracking).
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