Solar Air Conditioning in South Africa: Sizing, Hybrid AC/DC Units and 2026 Prices
Air conditioning is the single heaviest load most South African homes add, and it peaks at exactly the time solar generates most. That coincidence is what makes cooling one of the best things you can put behind a solar system, and it is why the wrong aircon undoes the whole benefit.
Why cooling and solar fit together so well
Most household loads are worst in the evening. Cooling is the exception: demand rises with the sun and peaks in the early afternoon, within an hour or two of peak generation. A house cooled between 11:00 and 16:00 is being cooled largely on power the array is producing anyway, which would otherwise be exported for less than it is worth.
It also works in your favour thermally. Cooling the structure during the day means the building coasts into the evening, so the aircon works less after dark when you are running on battery.
Inverter aircon, or the whole idea fails
A fixed-speed air conditioner runs the compressor flat out, then stops, then starts again. Those start-up surges are brutal on an inverter and a battery, and the duty cycle is inefficient.
An inverter air conditioner varies compressor speed instead. It draws a fraction of the power once the room reaches temperature, and it does not slam the system with repeated start surges. On a solar installation this is not a nice-to-have, it is the difference between a workable load and one that trips your system.
Hybrid AC/DC units: the specialist option
A hybrid AC/DC solar air conditioner takes DC directly from panels as well as AC from the inverter or grid. When the sun is out it runs largely or entirely on its own DC input, so it barely touches your inverter or battery at all.
The trade-off is that it needs its own panels and its own DC run, so it is more installation work. It suits a room you cool heavily during the day, or a site where you do not want to enlarge the main system just to carry cooling.
Sizing: BTU to room size
Undersize it and it runs constantly without reaching temperature, which costs more than the right unit. Oversize it and it short-cycles, cooling the air without removing humidity.
| Capacity | Suits roughly | Typical use |
|---|---|---|
| 12 000 BTU | up to about 20 m² | Bedroom, small office |
| 18 000 BTU | about 20 to 35 m² | Large bedroom, small lounge |
| 24 000 BTU | about 35 to 50 m² | Lounge, open-plan living |
| 30 000 to 36 000 BTU | about 50 to 75 m² | Large open-plan, light commercial |
Adjust upward for a west-facing room, a poorly insulated ceiling, large unshaded glazing or a high roof. Those factors move a room a full size bracket more often than people expect.
Solar air conditioner prices, 2026
Hybrid AC/DC solar units
| Unit | Price incl. VAT |
|---|---|
| Deye Hybrid ACDC Solar Air Conditioner 12000BTU | R13Â 170 |
| Deye Hybrid ACDC Solar Air Conditioner 18000BTU | R17Â 110 |
| Deye Hybrid ACDC Solar Air Conditioner 24000BTU | R21Â 940 |
Standard inverter units
Can your system carry it?
Before adding cooling to an existing installation, check three things. The inverter headroom: add the aircon’s running draw to your existing simultaneous load and confirm you are still inside the inverter rating. The start-up behaviour: inverter units are gentle, but confirm the surge against your inverter’s capability. And the battery, only if you intend to cool after dark, which is expensive. Cooling on daylight is the cheap version.
Frequently asked questions
Can I run an air conditioner on solar?
Yes, and daytime cooling is one of the better uses of a solar array because generation and cooling demand peak at similar times. Use an inverter unit, and check the load against your inverter rating.
What size solar system do I need to run an aircon?
It depends on the unit and how long it runs, but a 12 000 BTU inverter unit running through the middle of the day is a load most 5kW to 8kW hybrid systems carry without difficulty, provided the array is sized for it.
Is a hybrid AC/DC unit worth it over a normal inverter aircon?
If you cool heavily during daylight and want to avoid enlarging the main system, yes. If cooling is occasional or mostly in the evening, a standard inverter unit on the existing system is simpler and cheaper to install.
Will running aircon at night drain my battery?
Quickly, yes. Cooling is a heavy sustained load. Cool the house during the day, keep it closed up, and let the structure carry you into the evening.
Next step
Browse air conditioning, check your headroom with the sizing guide, or size storage with the evening peak method.
