What Does Air Conditioning Really Cost on Your Bill? Decoding kWh Consumption in 2026
L'équipe Proclimo
13 Sep 2026 - 07 min read
"My air conditioner is rated 3.5 kW, so it costs me 3.5 kWh per hour, right?" It's the question installers hear most often since the 5.5% VAT rate sent air-to-air heat pump installations soaring. And the answer is no: that 3.5 kW figure isn't electricity, it's the cooling (or heating) delivered. The electricity actually drawn is closer to 0.7 to 1.1 kW under normal conditions. In other words: a factor of 3 to 5 between what people think they're paying and what they actually pay.
This misunderstanding is costly in both directions. Some households don't dare switch on their air conditioner in the middle of a heatwave for fear of an outrageous bill; others leave it running at 19°C with the windows ajar and discover the damage in November. This article offers the only genuinely useful thing: an honest calculation method, verifiable orders of magnitude, and the three or four settings that really change the final figure.
Cooling capacity vs. power input: don't confuse the two figures
Three quantities sit side by side on a wall-mounted split unit's spec sheet, and only one of them matters for your bill.
- Cooling capacity (or heating capacity in heating mode), expressed in kW: this is the thermal energy delivered into the room. It's the source of the salesperson's "2.5 kW", "3.5 kW" or "5 kW".
- Power input, also in kW: the electricity consumed by the compressor, the fans and the electronics. This is what your Linky meter records.
- The ratio between the two, called EER in cooling and COP in heating, is the instantaneous efficiency. A modern air-to-air heat pump commonly posts a COP of 4: 1 kWh of electricity → 4 kWh of heat.
Energy labels, however, don't talk about COP but about SEER (cooling) and SCOP (heating), which are seasonal efficiency ratings calculated over a temperature profile representative of a full season, in line with European Regulation 206/2012 and standard EN 14825. Those are the figures to use for an annual calculation — not the nominal COP, which is always more flattering.
| Energy class (cooling) | Indicative SEER | Interpretation |
|---|---|---|
| A+++ | ≥ 8.5 | Premium, very well-sized inverter |
| A++ | 6.1 – 8.5 | Standard for good 2026 wall-mounted models |
| A+ | 5.6 – 6.1 | Recent entry-level |
| A | 5.1 – 5.6 | Older generations, portable monoblocs |
A portable monobloc air conditioner, lacking an outdoor unit and because of the warm air it draws from the room, often tops out at around SEER 2.6 to 3.0: for the same comfort, it uses two to three times more than a fixed split. It's the most dramatic gap in the whole sector.
The formula to remember (and two worked examples)
The calculation fits on one line:
Annual consumption (kWh) = annual thermal demand (kWh) ÷ SEER or SCOP
And for a quick hourly estimate:
Hourly cost (€) = power input (kW) × price per kWh (€)
As of 1 September 2026, the regulated electricity tariff on the base option sits at around €0.20 to €0.21 including tax per kWh, based on the changes published by the Commission de régulation de l'énergie; on the off-peak option, it often drops below €0.17 at night. Let's use €0.20 for the examples, bearing in mind you should substitute the figure from your own contract — it appears in plain sight on your bill, on the "price per kWh excl./incl. tax" line.
Example 1 — cooling a 30 m² living room in summer. Wall-mounted split, 3.5 kW, SEER 7. In real operation, with inverter control, the average power input works out at around 0.5 kW over a typical day (the compressor modulates and almost never runs at full load).
- 8 hours a day × 0.5 kW = 4 kWh/day, i.e. €0.80/day
- Over 60 days of summer use: 240 kWh, roughly €48
Example 2 — heating 80 m² through the winter with an air-to-air heat pump. Heating demand estimated at 7,000 kWh of thermal energy for a properly insulated home. SCOP of 4.2.
- 7,000 ÷ 4.2 = 1,667 kWh of electricity, i.e. around €333 for the season
- Compare that with 7,000 kWh from conventional electric convector heaters: €1,400
It's in heating, not cooling, that the air-to-air heat pump makes the financial difference. Summer use, meanwhile, costs far less than most households fear: ADEME puts the air conditioning consumption of an equipped single-family home at between 150 and 600 kWh per year, depending on the climate zone and usage patterns.
Measure rather than estimate: the only figure that doesn't lie
All the calculations above are orders of magnitude. Your installation, your insulation and your habits create variations of up to threefold. Two simple ways to get the real number.
The Linky meter. Switch everything off except the air conditioner for one hour of steady operation, then read the index before and after: you get your hourly consumption in kWh directly. The Enedis customer portal also lets you enable the hourly load curve, which makes the consumption spike very clear when the compressor kicks in.
A dedicated measuring device. For a portable unit or a split plugged into a socket, a plug-in power meter with a kWh display costs about twenty euros and settles the debate in a single evening. For a unit hard-wired to a dedicated circuit — the most common case — you'll need a clamp meter or a monitoring module fitted in the consumer unit by an electrician, which reports consumption to your smartphone in real time.
Once you've taken the measurement, hold on to it: it's your benchmark. If the following year the same room, at the same temperatures, uses 30% more, you have a problem — a fouled heat exchanger, an incorrect refrigerant charge, clogged filters — not a drift in electricity prices.
The five settings that really move the bill
1. The temperature setpoint, by far the biggest lever
Every degree lower on the summer setpoint increases consumption by roughly 7%, according to ADEME. The agency recommends a gap between indoors and outdoors of 5 to 7°C maximum, with a setpoint rarely below 26°C. Going from 26 to 22°C therefore means nearly 30% more consumption — plus thermal discomfort when you step back outside.
In winter, the same logic in reverse: the French Energy Code sets the average heating temperature for residential premises at 19°C (article R241-26). Every degree above that costs roughly 7% more.
2. "Auto" fan mode, not minimum speed
Counter-intuitive but proven: throttling the indoor fan down to minimum "to save energy" forces the compressor to work longer to reach the setpoint. Automatic mode lets the machine pick the most efficient airflow/compressor pairing. The only case for manually lowering the speed is at night, for the noise.
3. Running with doors closed and shutters down
A split unit cools the volume you give it. Leaving doors open onto a hallway and a stairwell means doubling or tripling that volume. And since the leading source of heat gain in summer remains solar radiation through glazing, an exterior shading device — roller shutter, screen blind, or failing that a solar window film fitted on the inside — cuts the cooling demand before it even arises. CSTB measurements put the gain at 20 to 40% fewer solar heat gains, depending on orientation.
4. Time-of-day scheduling, matched to your contract
Since the overhaul of off-peak time slots that came into force in 2026, some households now have off-peak windows in the middle of the day in summer, in addition to overnight. In practice, pre-cooling the home during those windows and letting thermal inertia do the rest can bring the cost down by 10 to 15% for near-identical consumption. Check your exact time slots on your bill or in your supplier's customer portal: they have changed for many subscribers.
5. Cleaning the filters
Two clogged filters reduce airflow, and therefore efficiency, by 5 to 15%. An air conditioner cleaning kit with disinfectant spray for the heat exchanger is enough for routine maintenance every 4 to 6 weeks in peak season. Annual servicing by a professional remains mandatory for systems above 4 kW (decree no. 2020-912).
What air conditioning costs compared with the alternatives
To place air conditioning within a household budget, here are some orders of magnitude for cooling a 25 m² room for 8 hours, at €0.20/kWh.
| Equipment | Average power input | Cost / 8 h |
|---|---|---|
| Ceiling fan | 0.05 kW | €0.08 |
| Tower fan | 0.05 kW | €0.08 |
| Evaporative air cooler | 0.1 kW | €0.16 |
| Portable monobloc air conditioner | 1.0 kW | €1.60 |
| Fixed A++ inverter split | 0.5 kW | €0.80 |
There are two lessons here. First, a ceiling fan uses twenty times less than a split and lowers perceived temperature by 2 to 3°C: it's the most cost-effective companion in the whole line-up, though never a substitute during a severe heatwave. Second, the fixed split is cheaper to run than the portable despite its higher capacity — the opposite of what intuition suggests.
The billing traps you don't see coming
Oversizing. A unit that's too powerful for the room runs in short on/off cycles. Every compressor start-up draws a significant power surge, and inverter control loses all its benefit. A 5 kW split in a 12 m² bedroom will use more than a properly sized 2.5 kW unit, while dehumidifying less effectively. Insist that your installer provide a written heat load calculation, not a rule-of-thumb figure per square metre.
Your contracted power rating. Several splits starting up at once, on top of the oven and the water heater, can trip a 6 kVA supply. Upgrading to 9 kVA costs about twenty euros extra per year in standing charges — a decision best made before summer rather than on a Sunday in July.
Backup electric heating in winter. Many air-to-air heat pumps include, or are supported by, direct electric backup heating. Below −7°C, or during defrost cycles, efficiency collapses and the backup takes over at a COP of 1. Over a week of severe cold, the bill can double without anything being faulty. It isn't a breakdown, it's physics.
Permanent standby mode. A split left powered up draws 2 to 8 W continuously, i.e. 20 to 70 kWh a year for four units. Trivial on its own, but it's the equivalent of a month's cooling.
In summary
- Never confuse cooling capacity (the marketing figure) with power input (the billing figure): the ratio ranges from 3 to 5.
- For an annual estimate, divide your thermal demand by the SEER or the SCOP, never by the nominal COP.
- Measure at least once with a power meter or the Linky load curve: that's your reference point for spotting any drift.
- The three free levers — a sensible setpoint, solar shading and closed doors — matter more than any equipment upgrade.
- In heating, an air-to-air heat pump cuts the bill by a factor of 3 to 4 compared with convector heaters; in cooling, its real cost is far below common fears.
Sources: ADEME (guide "Se rafraîchir sans se ruiner"), European Regulation 206/2012 and standard EN 14825 for SEER/SCOP, Commission de régulation de l'énergie for 2026 regulated tariffs, French Energy Code article R241-26, decree no. 2020-912 on the maintenance of thermodynamic systems.
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