Conversion
Inverters
Converts DC to AC. Sized by power, not by energy — your largest simultaneous load plus the surge of whatever motor starts under it. This is the component most often undersized.
What to compare
- String, microinverter or hybrid — hybrid if you want battery backup
- Continuous output versus surge rating, and the surge duration
- Pure sine wave, always, for anything with a motor
- UL 1741 listing, or your utility will refuse interconnection
How to size it
Two numbers matter and they are not interchangeable. Continuous output must cover everything running at once; surge output must cover the largest single motor starting on top of that load. A well pump or air conditioner can draw three to seven times its running figure for a fraction of a second, and an inverter that cannot supply it will simply fault out. Note also that grid-tied output on a standard 200A residential service is capped near 7.6 kW by the NEC 120% busbar rule — a panel constraint, not a roof one, and the reason many systems stop short of what the roof could hold.
Mistakes that cost money
- Sizing to running watts only
- The nameplate on a fridge or pump describes steady-state draw. Starting draw is several times higher. Systems sized on running watts alone work fine until the compressor cycles.
- Buying a modified sine wave inverter
- Cheaper, and fine for a heating element or an incandescent bulb. Anything with a motor, a circuit board or a switching power supply — which today means nearly everything — runs hot, buzzes, or refuses to start. Pure sine wave is the default for a reason.
- Overlooking idle consumption
- An inverter left on draws power doing nothing, often 20-50W. Over a day that is 0.5-1.2 kWh gone before a single appliance runs, which on a small off-grid bank is a significant fraction of the storage.
- Missing the utility approval list
- For anything grid-tied, the utility usually requires equipment from an approved list meeting UL 1741 and IEEE 1547. Buying first and asking afterwards is how a system ends up unable to get permission to operate.
Options
No inverters listed yet. We only list components we can price and specify accurately, and we are still onboarding retailers for this category.
The guides below cover how to choose one in the meantime — they are what we would tell you before recommending any specific product.