Selection & System Sizing
How Many Solar Panels Are Needed for a 24,000 BTU Air Conditioner?
A practical sizing method using the air conditioner's measured input power, operating hours, peak-sun hours and system losses.
Quick answer
Under representative daytime assumptions, 2.5–4.0 kWp can be a useful early planning range for a 24,000 BTU inverter air conditioner—not a fixed PV capacity for every 24,000 BTU unit. Actual sizing must use the unit's rated or measured electrical input, expected runtime, local peak-sun hours and system losses. Battery capacity must be calculated separately for operation after sunset.
Calculation at a glance
Convert the AC load into PV capacity.
Round upward, then validate string voltage, controller and inverter limits.
Rounded example module counts
Start with electrical input, not cooling capacity
24,000 BTU/h is the cooling output. It is not the electrical power consumed. Two units with the same cooling rating can draw different power because of efficiency, compressor technology, ambient temperature and operating mode.
Use the nameplate or technical sheet values for:
- rated input power in watts or kilowatts;
- maximum input current;
- inverter or fixed-speed compressor type;
- voltage, frequency and phase;
- expected operating hours and day/night split.
If the documentation lists only EER or COP, convert cooling output to electrical input before sizing. For procurement, measured consumption under representative hot-weather conditions is better than a nominal estimate.
What changes the final result
The calculation block uses an illustrative 1.8 kW average input, six operating hours, five peak-sun hours and a 1.30 loss factor. A final design replaces each input with site and equipment data. Module string voltage, inverter clipping, shading, lowest-sun month and other simultaneous loads can move the practical result.
A planning loss factor of 1.25–1.4 is a typical early-stage range for temperature, inverter, wiring, soiling and operating margin. It is not a guaranteed Sharxell system value.
Battery sizing for evening or overnight use
PV capacity and battery capacity answer different questions. For four hours of operation after sunset at an average 1.8 kW, the AC requires 7.2 kWh. With an assumed 90% inverter efficiency and 80% usable battery depth of discharge:
Nominal battery = 7.2 ÷ 0.90 ÷ 0.80 = 10 kWh
Battery manufacturer limits, temperature derating, aging reserve and other loads can increase this figure.
Procurement checks
- Do not approve a quotation based only on “24,000 BTU.”
- Confirm the exact AC model or obtain a nameplate photo.
- Separate daytime solar operation from nighttime battery operation.
- Include all simultaneous loads, not only the air conditioner.
- Check inverter continuous power, surge capability, DC voltage window and local voltage/frequency.
- Use local monthly solar data; the lowest-sun design month may control an off-grid system.
The example is a sizing illustration. Final module quantity, battery capacity and inverter selection require site and load data.
FAQ
Can a 24,000 BTU air conditioner run directly from solar panels?
It should run through a correctly sized inverter or solar-air-conditioner controller. A grid, battery or other stabilizing source may also be required because PV output changes with clouds and temperature.
Is a 5 kW inverter always enough?
Not always. Confirm continuous input power, compressor starting behavior, power factor, other simultaneous loads and the inverter's surge rating.