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How much does air conditioning cost to run? Real euro figures
The first-summer-with-AC question — answered with 2026 numbers, real Spanish tariffs and the honesty to say half the consumption depends on how you use it.
Quick summary
A modern 3.5 kW inverter split cooling a living room draws on average 0.4–0.8 kWh per hour of real use ≈ €0.08–0.20 per hour at 2026 tariffs. Typical summer use (8 h/day): €20–40/month. A 15-year-old or dirty unit can double that.
The consumption table by unit type
Real average draw (not the nameplate figure — inverters modulate) with a maintained unit and a sensible 25 °C setpoint:
| Unit | Avg. draw/hour | Cost/hour* | 8 h/day · month |
|---|---|---|---|
| 2.5 kW split (bedroom) | 0.3–0.5 kWh | €0.06–0.13 | €15–30 |
| 3.5 kW split (living room) | 0.4–0.8 kWh | €0.08–0.20 | €20–48 |
| 2×1 multi-split (both running) | 0.7–1.2 kWh | €0.14–0.30 | €34–72 |
| Whole-home ducted (zoned) | 1.0–1.8 kWh | €0.20–0.45 | €48–108 |
| 12+-year-old unit (on/off) | ×1.5–2 of the above | — | double |
*At an average 2026 price of €0.20–0.25/kWh. With time-of-use tariffs, pre-cooling the home before peak hours cuts another 20–30%.
What consumption really depends on
- The setpoint: every degree below 24–25 °C adds 7–8% consumption. From 25 to 21 °C the bill grows ~30%.
- The unit's condition: a dirty coil and filters force the compressor to work harder for the same cold — up to 20% excess that the annual clean removes.
- Age: a current A+++ inverter uses half what a 2010 on/off unit does for the same comfort. That is the mathematical case for replacement.
- Insulation and sun: a lowered blind on the afternoon façade saves more than any "eco" button.
- Sizing: an undersized unit never stops; an oversized one cycles inefficiently. The calculated one modulates low — where the inverter shines.
The 6 habits that cut the bill
- A steady 25 °C beats bursts at 21 °C: inverters modulate better than they restart.
- Blinds and awnings on the afternoon façade — the cheapest kWh is the one that never comes through the glass.
- Filters washed monthly in season (yourself, with water) plus the professional annual clean.
- Sleep mode at night: the setpoint drifts up while you sleep — same comfort, less draw.
- A ceiling fan as ally: moving air lets you raise the setpoint 1–2 °C at the same feel.
- Scheduling around your tariff: pre-cool in off-peak hours if you have time-of-use pricing.
FAQ
How much does air conditioning cost to run? Real euro figures — FAQ
How much does running the AC all night cost?
A bedroom split (2.5 kW) in sleep mode for 8 hours draws 2–3 kWh ≈ €0.45–0.75 per night at 2026 tariffs. Less than most people expect — a low-régime inverter is very efficient.
Does the same unit cost more in cooling or heating mode?
In Valencia, winter heating draws somewhat more per hour (bigger temperature gap) but runs fewer hours than August cooling. Over the year, summer dominates the area's climate bills.
Is replacing an old unit worth it just for consumption?
With daily seasonal use, yes: a current A+++ inverter cuts up to 50% versus a 2010 on/off unit — at 3–4 months of use a year, replacement (from €640) pays back in 3–5 summers, sooner if the old one also needs repairs.
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