Air conditioning on solar panels is almost the perfect match. Your air con cools hardest when the sun is beating down, and that is exactly the moment your panels generate the most power. Cooling demand and generation both peak around midday. So you use the solar power directly yourself, without having to export it for a low payment.
The numbers in short. A modern split air conditioner uses around 200 to 400 kWh per summer for cooling. You cover that with 1 solar panel (a panel of about 450 Wp generates roughly 400 kWh a year in our climate, source: Milieu Centraal). If you also use the air con to heat, count on roughly 1,000 kWh a year and about 3 panels. A single split air con costs around £1,500 to £3,000 including installation (source: various air con installers).
Below is the full story. How much an air con really uses, why it is so economical, how many panels you need, and why this combination becomes a strong plan precisely after 2027 (when net metering ends).
Why air conditioning and solar panels go so well together
This is the heart of it, and it is exactly the point most articles do not work out.
An air con runs hardest when it is hot outside. On a day like that the sun sits high and bright, and your panels perform at their best. So the demand for cooling and the generation of solar power run almost in step. During the day, when you do not even need to be home, the air con cools on power you are generating yourself at that very moment.
Compare that with an average household without air con. It uses only around 30 percent of the solar power it generates directly itself (source: Milieu Centraal). The rest goes onto the grid during the day, because there is nobody home to use it. RVO gives a range of 25 to 40 percent self-consumption without a home battery.
An air con changes that picture. It turns part of your “lost” afternoon generation into cooling in the house. Your self-consumption goes up, exactly at the moment you would otherwise be exporting. That is the big win, and that win only gets bigger after 2027 (more on that further down).
The match profile side by side:
| Time of day | Solar generation | Cooling demand air con |
|---|---|---|
| Morning (7-10am) | Rising | Low |
| Midday (11am-4pm) | Peak | Peak |
| Late afternoon (4-7pm) | Falling | Still high (house has warmed up) |
| Evening/night | Zero | Low to zero |
The only small mismatch sits at the end of the day. A house that has warmed up during the day keeps needing cooling in the evening, while the panels are already delivering almost nothing by then. If you want to run that last bit on solar power too, you need a home battery. But the bulk of the cooling simply falls within the sunlight hours.
How much does an air con actually use?
Less than most people think. That comes down to two things: modern inverter technology and high efficiency.
A modern split air con uses about 0.4 to 0.8 kWh per hour while cooling, depending on the output, the outside temperature and how cool you want it (source: various air con trade sources). When starting up a warm house that usage spikes higher for a moment, after which an inverter air con drops back to a low, constant draw to hold the temperature.
Work that out over a whole summer season and you land on:
- Cooling only: about 200 to 400 kWh a year, assuming around 50 hot days with a few hours of cooling per day.
- Cooling and heating: about 1,000 kWh a year, if you also bring the air con in during winter and the shoulder seasons to heat.
Heating is the biggest chunk. Cooling really is only a small draw.
SEER and SCOP: why an air con is so economical
Two terms you come across when comparing air cons, and they explain exactly why an air con costs little power.
SEER (Seasonal Energy Efficiency Ratio) tells you how much cooling you get per kWh of power, measured over a whole cooling season. A SEER of 8 means: for every kWh of power that goes in, 8 kWh of cooling comes out. Modern split air cons often sit around SEER 6 to 8.5 or higher.
SCOP (Seasonal Coefficient of Performance) does the same for heating. A SCOP of 4 means 4 kWh of heat per kWh of power. An air con is simply a heat pump: it moves heat rather than generating it. That is why heating with an air con is far more economical than with an electric heater (which sits at SCOP 1: 1 kWh of power gives 1 kWh of heat).
Rule of thumb when buying: look at the energy label. For cooling and heating you want at least A++, and A+++ is better. The higher the SEER and SCOP, the less power (and so the fewer panels) you need for the same comfort.
How many solar panels do you need for an air con?
The sum is simple. You divide the air con’s yearly usage by the yearly output of one panel.
A panel of about 450 Wp generates roughly 400 kWh a year in our climate (source: Milieu Centraal; output depends on orientation, tilt angle and shade).
| Air con use | Usage per year | Panels needed (at 400 kWh) |
|---|---|---|
| Cooling only | 200 to 400 kWh | 1 panel |
| Cooling + heating | around 1,000 kWh | 2 to 3 panels |
Example. A split air con with 2.5 kW of cooling output that you use in summer draws around 300 kWh. That is 300 / 400 = 0.75 of a panel. So one panel covers your cooling season with room to spare.
An important nuance: this is a bookkeeping match on a yearly basis. It says your panels generate enough across the year to feed your air con. Whether that power is also available at the right moment depends on that match profile. For cooling it lines up well (sun and cooling demand run in step). For heating it lines up badly, and that is the honest flip side.
The honest flip side: heating in winter
An air con can heat too, and it is economical (SCOP 4 or higher). But this is exactly where the match story falls apart.
You heat in winter and the shoulder seasons. That is precisely when your panels generate little. A solar panel delivers a fraction of its summer output in the dark months. So the power your air con uses to heat in winter comes largely from the grid, not from your own roof.
On paper the yearly sum still adds up: your panels generate enough across the whole year. But in practice you export a lot in summer (or use it yourself for cooling) and buy power in winter to heat. As long as net metering still runs, you cancel that out against each other. After that, no longer.
Put briefly: cooling on solar power is a bullseye, heating on solar power is half a story. Be honest with yourself about that if you mainly see the air con as heating.
Why this gets smarter now that net metering is ending
This is the strongest argument, and most articles do not work it out.
On 1 January 2027 the net metering scheme ends (source: Rijksoverheid). From that moment on:
- You can no longer offset exported power against what you draw.
- You get an export payment from your energy supplier for power you export.
- That payment must be at least 50 percent of the bare supply rate until 2030 (source: Rijksoverheid).
In practice that payment can turn out low, and on sunny days with a lot of supply it can sometimes head towards zero. Power you use directly yourself is then worth far more than power you export.
And a cooling air con happens to use power directly, at the brightest sun moment of the day. Instead of sending your afternoon generation onto the grid for peanuts, you turn it into cool air in the house. You then save the full supply rate you would otherwise have paid in the afternoon, while exported power will soon bring in next to nothing.
Seen that way, an air con after 2027 is a way to push up your self-consumption during the day, just like a home battery or charging an electric car during the day. Only here you get cool air (and comfort) in return.
What does an air con cost, and does it pay off?
A single split air con (one indoor unit, one outdoor unit) costs around £1,500 to £3,000 including installation (source: various air con installers). Several indoor units (multi-split) or an awkward fitting run higher.
Whether it pays off depends on what you use it for.
Purely for cooling an air con essentially never hard-pays for itself financially, because cooling is a comfort expense, not a saving. You are not comparing it with something cheaper, you are buying cool air you did not have otherwise. You do keep the power costs low though: cooling on your own solar power costs you almost nothing extra in summer, certainly if your panels are already up.
For heating it can be a saving, if the air con replaces (part of) your gas use. An air con that heats at SCOP 4 is considerably more economical than an electric heater, and in the shoulder season it can be cheaper than firing up the boiler. The payback time then depends entirely on your gas price, power price and how much you really put the air con to work.
Sanity check: do not expect miracles on your energy bill from a single air con. It is comfort with an economical edge, not an investment that pays itself back in a few years the way solar panels do.
Do you get a subsidy? Mind the ISDE trap
This is where a lot of people trip up. An ordinary split air con usually does not qualify for the ISDE subsidy.
The ISDE (Investment Subsidy for Sustainable Energy) subsidises heat pumps, but only air-to-water, ground-to-water and hybrid heat pumps that deliver your heating or hot water via a water circuit (source: RVO). An air con is technically an air-to-air heat pump: it only heats and cools the air in a room, without any link to radiators, underfloor heating or a hot water cylinder. That puts it outside the ISDE.
In short: do not count on a national subsidy for a standalone air con. Local council schemes do sometimes run, so always check your own municipality. But the big national pot is closed to air-to-air air cons.
Can an air con run on a single standalone panel (off-grid)?
A question that often comes up: can I connect a panel straight to my air con, separate from the grid? Technically sometimes, financially rarely smart.
An air con needs a stable, constant power supply. A single panel delivers fluctuating power that can simply drop away with one cloud. To cushion that you need an inverter, and to run without the grid you also need batteries. That makes an off-grid setup expensive and complex, while you get little back for it.
Far more logical: just connect your panels to your consumer unit (grid-tied), like a normal solar installation. The air con draws its power from the house, and on sunny afternoons that power comes largely from your own panels of its own accord. You do not need to link anything directly. The grid absorbs the fluctuations, and you benefit from the match between generation and cooling demand without any hassle.
A genuine off-grid air con is only interesting somewhere without a grid connection (think of a garden room or a static caravan far from the consumer unit), and even then you do the sums sharply on whether it is worth it.
Common mistakes
Thinking an air con guzzles power. Cooling costs a modern inverter air con only 200 to 400 kWh per summer, covered by a single panel. The fear of a sky-high energy bill is unfounded when it comes to cooling.
Wanting to plug the air con straight into a panel. Grid-tied works better and simpler. On sunny afternoons your air con runs largely on your own solar power of its own accord, without any separate wiring.
Counting on the ISDE subsidy. An air-to-air air con falls outside the national ISDE. Only air-to-water, ground-to-water and hybrid heat pumps qualify (source: RVO).
Looking only at the price, not at SEER and SCOP. A cheap air con with a low energy label uses more power and needs more panels. Choose at least A++, preferably A+++.
Overestimating heating on solar power. You heat when the sun is low and your panels deliver little. On a yearly basis the sum adds up, but the winter power comes largely from the grid.
Frequently asked questions
How many solar panels do I need for an air con?
For cooling only, 1 panel is usually enough. An air con uses around 200 to 400 kWh per summer, and a panel of about 450 Wp generates roughly 400 kWh a year in our climate (source: Milieu Centraal). If you also use the air con to heat, count on around 1,000 kWh a year and 2 to 3 panels.
Does my air con really run on my own solar power?
For cooling, largely yes. The air con cools hardest on hot, sunny days, exactly when your panels generate the most. You then use that generation directly yourself. For heating the opposite is true: you do that in winter, when your panels deliver little, so the power then comes mainly from the grid.
Is an air con on solar panels worthwhile after net metering ends?
Yes, especially then. From 1 January 2027 net metering ends (source: Rijksoverheid) and exported power brings in little. A cooling air con uses your solar power directly at the brightest sun moment, instead of you exporting it for a low payment. That way you save the full supply rate you would otherwise have paid in the afternoon.
Does an air con qualify for the ISDE subsidy?
No, usually not. An air con is an air-to-air heat pump, and that falls outside the ISDE. Only air-to-water, ground-to-water and hybrid heat pumps qualify (source: RVO). Do always check whether your council has a scheme of its own though.
What does an air con cost including installation?
A single split air con (one indoor and one outdoor unit) costs around £1,500 to £3,000 including fitting (source: various air con installers). Several indoor units or an awkward installation run higher.
Do I need a home battery to run my air con on solar power?
No, not for cooling. The bulk of the cooling demand falls within the sunlight hours, so you are already using your generation directly. A battery mainly helps with after-cooling in the evening, when the house is still warm and the panels deliver nothing more. It is not necessary.
In short
Air conditioning on solar panels is almost a perfect match: cooling demand and generation both peak around midday, so you use your solar power directly yourself. Cooling costs only 200 to 400 kWh per summer (1 panel), cooling plus heating around 1,000 kWh (2 to 3 panels). Heating on solar power is the weak point, because you do it when the panels deliver little.
The strongest argument comes after 2027. When net metering ends, power you use yourself becomes worth far more than power you export. A cooling air con turns your afternoon generation into comfort, which is exactly what you want then.
Want to know what an air con on solar panels brings for your roof and your usage, and how much you will consume yourself after 2027? Work it out with Fred’s energy-saving platform: energie-verpulveraar.fredsbouwtekeningen.nl. That way you see in black and white what the smartest choice is before you have an air con fitted.