Can You Run an AC on Solar Panels?
How many units an air conditioner really uses, the solar size you need for one, two or three ACs, and whether a battery can run one during a power cut.
Rainbow Solar Energy Team
6 min read
Updated
In this article
Key takeaways
- Yes. With net metering, an on-grid system can offset all the units your AC uses, day and night.
- A 1.5-ton inverter AC uses about 1–1.5 units an hour, so 8 hours a day is roughly 10 units.
- Plan about 2.5–3 kW of solar per AC used 8 hours a day, on top of your other loads.
- Running an AC in a power cut needs a large battery: about 10 kWh for 4 hours.
In Tamil Nadu, the air conditioner is usually the single biggest reason for a high EB bill, and the reason many homes jump into expensive tariff slabs. The good news: rooftop solar is a perfect match, because the hottest, sunniest hours are exactly when ACs run hardest.
How many units does an AC use?
| AC type | Units per hour (approx.) | 8 hours a day | Per month |
|---|---|---|---|
| 1 ton inverter (5-star) | 0.6 – 0.8 | 5 – 6.5 | 150 – 195 |
| 1.5 ton inverter (5-star) | 0.9 – 1.2 | 7 – 10 | 215 – 290 |
| 1.5 ton inverter (3-star) | 1.1 – 1.5 | 9 – 12 | 265 – 360 |
| 1.5 ton non-inverter | 1.5 – 1.8 | 12 – 14.5 | 360 – 430 |
| 2 ton inverter | 1.4 – 1.9 | 11 – 15 | 335 – 455 |
Actual use depends on room size, insulation, thermostat setting (24–26°C saves a lot) and outdoor temperature.
What size solar system do you need?
Each kW of solar makes about 120 units a month in Tamil Nadu. Add your AC units to the rest of your home's use:
| Your home | Typical monthly units | Recommended solar |
|---|---|---|
| Basic loads + one 1.5-ton AC (8 hrs/night) | 350 – 450 | 3 – 4 kW |
| Basic loads + two ACs | 550 – 700 | 5 kW |
| Basic loads + three ACs | 800 – 1,000 | 7 – 8 kW |
Know your units? Switch our solar savings calculator to “EB units” and enter them for an exact system size and savings.
But ACs run at night. Does solar still help?
Yes. With net metering, the units your panels export during the day are credited against what your AC draws at night. Over the two-month billing cycle, your net units fall, and so does your slab.
Can a battery run my AC during a power cut?
It can, but it's expensive. Running one 1.5-ton AC for 4 hours plus essential loads needs roughly a 10 kWh lithium battery and a 5–6 kW hybrid inverter. Most families keep ACs off the backup circuit and back up fans, lights, Wi-Fi and the fridge instead. See hybrid solar and solar + battery for power cuts.
Size your solar around your ACs
Tell us how many ACs you run and for how long. We'll design a system that covers them.
Tips to cut AC units further
- Set the thermostat to 24–26°C: each degree lower adds roughly 6% to consumption.
- Use the ceiling fan with the AC to feel cooler at a higher setting.
- Clean AC filters every 2–3 weeks in summer.
- Shade west-facing windows and the outdoor unit.
Written by our solar engineers and subsidy specialists, who design and install rooftop systems for homes, societies and businesses across Tamil Nadu. Figures are indicative and reviewed regularly; your free site survey gives exact numbers for your roof.
