On-grid, hybrid or off-grid
An on-grid inverter is the cheapest route to net metering, but it shuts down during an outage. A hybrid inverter does net metering and keeps a backup circuit alive from batteries. Off-grid makes sense only where there is no reliable K-Electric supply.
For most Karachi homes the honest answer is hybrid, because outages are a fact of life and you will eventually want storage even if you skip it at day one.
Sizing: inverter kW versus array kW
Slight over-sizing of the panel array against inverter capacity is normal and desirable — panels rarely hit nameplate output in real conditions. What is not acceptable is an undersized inverter that clips your best production hours all summer.
Check the maximum DC input, the number of MPPT trackers and the string voltage window. Roofs with two orientations need two MPPTs, otherwise the shaded or lower-yield side drags the whole string down.
Surge capacity for air conditioners and pumps
Motors draw several times their running current at startup. If you plan to run ACs or a water pump on the backup output, the inverter's surge rating and how long it can hold it decide whether the system survives startup or trips.
Ask for the surge figure in watts and seconds, not a vague 'AC supported' claim on a brochure.
- Two MPPT trackers for multi-orientation roofs
- Surge rating stated in watts and duration
- Certified for K-Electric net metering
- Local service centre and spare availability
- Temperature derating curve suitable for 45°C ambient
Heat, dust and derating in Karachi
Inverters lose output when they overheat. A unit mounted on a sun-facing exterior wall with no shade will derate through the hottest hours — exactly when your array is producing most. Mount it shaded, ventilated and away from salt-heavy exposure.
Dust ingress and corrosion are why enclosure rating and mounting location deserve as much attention as the brand name.
Warranty and net-metering approval
Only inverters on the approved list clear K-Electric net-metering scrutiny smoothly. We supply and install approved models, handle the documentation, and record the model number on your quotation so what is delivered is what was quoted.
Frequently asked questions
- Which inverter is best for net metering in Karachi?
- Any approved grid-tie or hybrid inverter with the correct capacity and certification. The right choice depends on your array size, roof orientations and whether you want battery backup.
- Can one inverter handle both net metering and battery backup?
- Yes, that is exactly what a hybrid inverter does — it exports surplus to K-Electric and keeps a backup circuit running from the battery during outages.
- How long do solar inverters last?
- Typically ten years or more with good ventilation and clean installation, which is shorter than panel life. Budget for one replacement over the life of the system.