Solar Inverter Sizing for AC + Fridge + Pump Load Pakistan 2026 — Surge, Continuous, Peak Calc
What solar inverter size do I need for AC + fridge + pump in Pakistan?
Match inverter continuous wattage to total RUNNING wattage of backed-up loads, AND check that inverter SURGE capacity covers the highest single-motor LRA. Typical Pakistani sizing: 3 kW inverter for 1× 1-ton AC + fridge + lights/fans (~2.5 kW running); 5 kW inverter for 1× 1.5-ton AC + fridge + pump + lights (~4 kW running); 7-8 kW inverter for 2× ACs or 1× 2-ton AC + full house (~6 kW running). The hidden trap: motor LRA (Locked Rotor Amps) at start-up is 4-7× running current. A 1.5-ton AC at 1500W running draws 7000-9000W during the 0.5-second compressor start. Inverter without 2× surge rating shuts down on every AC start.
Continuous vs surge vs peak — the three numbers
- Continuous power (W or VA): can deliver indefinitely. e.g., "5 kW" inverter = 5,000W continuous.
- Peak / Surge power: can deliver for short duration. Pure-sine quality inverters typically 2× continuous for 5-10 seconds.
- Cold-start surge / motor LRA tolerance: ~3× continuous for 0.1-0.5 sec. Required for compressor starts.
Pakistani load profile — what each appliance actually draws
| Appliance | Running W | Surge W (start) | Surge ratio |
|---|---|---|---|
| 1-ton AC (inverter type) | 1,000 | 2,500-4,500 | 2.5-4.5× |
| 1.5-ton AC (inverter type) | 1,500 | 4,000-7,000 | 2.7-4.7× |
| 2-ton AC (inverter type) | 2,200 | 6,000-9,000 | 2.7-4.1× |
| 1.5-ton AC (non-inverter / fixed-speed) | 1,800 | 7,500-10,000 | 4-6× |
| Fridge (200L) | 120 avg / 250 cycle peak | 600-1,200 | 5-10× |
| Deep freezer | 200 | 800-1,500 | 4-7× |
| Submersible water pump 1HP | 750 | 3,000-5,000 | 4-6× |
| Centrifugal pump 0.5HP | 370 | 1,400-2,200 | 4-6× |
| Ceiling fan | 70 | 150 | ~2× |
| LED ceiling light (10W bulb) | 10 | 15 | ~1.5× |
| Microwave oven | 900 | ~1,000 | ~1× (resistive) |
| Iron / kettle | 1,500-2,200 | ~1× (resistive) | ~1× |
| Geyser (instant electric) | 3,000 | ~1× | ~1× |
Worked example: Pakistani 3-bedroom house typical summer load
Loads to back up via solar inverter:
- 1 × 1.5-ton AC (inverter type): 1,500 W running, 6,000 W surge
- 1 × fridge: 120 W avg, 1,000 W surge
- 4 × ceiling fans: 4 × 70 = 280 W
- 8 × LED lights: 8 × 10 = 80 W
- 1 × TV + WiFi: 150 W
- 1 × small water pump (0.5HP, runs occasionally): 370 W running, 2,000 W surge
Total continuous (AC + fridge + fans + lights + TV): 1,500 + 120 + 280 + 80 + 150 = 2,130 W. Worst-case if AC + pump start simultaneously: 6,000 + 2,000 = 8,000 W surge needed for ~1 second.
Inverter recommendation: 5 kW continuous, 10 kW surge (2× rating). The pure-sine hybrid 5 kW class typically delivers ~8-10 kW for 5 seconds = covers worst-case AC + pump simultaneous start.
Pakistani inverter capacity tiers
| Inverter size | Continuous | Surge (typical 2×) | Suitable for |
|---|---|---|---|
| 1 kW | 800-1,000 W | ~2,000 W | Lights + fans + TV only — NO AC |
| 3 kW | 2,500-3,000 W | 5,000-6,000 W | 1× 1-ton AC + fridge + lights |
| 5 kW | 4,500-5,000 W | 9,000-10,000 W | 1× 1.5-ton AC + fridge + pump + full lighting |
| 8 kW | 7,500 W | 15,000 W | 2× ACs OR 1× 2-ton AC + house OR small commercial |
| 10-15 kW | 10,000-15,000 W | 20,000-25,000 W | Commercial / large house / pharmacy / clinic |
Why "5 kW inverter for 5 kW load" is wrong
Three reasons Pakistani solar installers under-size:
- Surge calculation missed: total RUNNING load = 4 kW but worst-case surge = 8-10 kW. A 5 kW inverter with 10 kW surge handles it. A 5 kW inverter with 6 kW surge shuts down on every AC start.
- No headroom for future loads: install 5 kW today, add a 2nd AC next year, need 7-8 kW. Plan for 25-40% headroom.
- Inverter efficiency curve: most hybrid inverters peak efficiency at 50-80% load. Running at 95% load all day reduces efficiency 3-5% AND ages the unit faster. Right-sizing means inverter spends most time at 50-70% load.
Hybrid vs grid-tie vs off-grid for Pakistani home
| Type | Uses solar? | Uses battery? | Backs up grid outage? | Best for Pakistani home |
|---|---|---|---|---|
| Grid-tie (on-grid) | Yes | No | NO (shuts off in outage) | Net-metering only — but useless during load-shedding |
| Hybrid | Yes | Yes | YES (battery + solar) | BEST for Pakistan — solar day, battery night, grid emergency |
| Off-grid | Yes | Yes (mandatory) | N/A (no grid connection) | Rural sites without grid; expensive battery sizing |
Common Pakistani inverter-sizing mistakes
- Buying "5 kW" inverter rated 5 kVA, not 5 kW — at PF 0.8, 5 kVA = 4 kW real power. Buy by kW not kVA.
- Ignoring surge for AC compressor — saving Rs. 30K on a smaller inverter that can't start your AC = Rs. 100K replacement when inverter trips repeatedly + AC compressor damage.
- Modified-sine wave inverter for an AC + fridge — saves Rs. 20K upfront, damages AC inverter board and fridge compressor within 18-24 months. Pure-sine only for inductive/electronic loads.
- Inverter and panel ratio mismatch — 5 kW inverter with 3 kWp panels = inverter under-utilised; 5 kW inverter with 8 kWp panels = inverter clips daily. Match panel array to inverter at 1.1-1.3× DC oversizing.
- Skipping the battery on the basis of net-metering savings — Pakistani net-metering post-Feb 2026 pays Rs. 8.13/unit. Self-consumption from battery saves Rs. 50+/unit. Battery beats export.
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Hybrid vs On-Grid vs Off-Grid Inverter · LiFePO4 Battery Sizing · Net-Metering Feb 2026 Deadline