I have just started looking for one of the newer 99% efficient inverters now available. I have this older 600w/ 1200 peak modified sine wave inverter but its peak efficiency is just 80%.
I refuse to live with a 20% loss over a few hundred bucks so am searching for one of the new 96 - 99% inverters being offered.
With luck they make these in the smaller watt sizes
100% efficient inverter: 175,000 kWh, $31,489 value (7000 kWh X $0.13 X 2.6% X 25 years)
98% efficient:
171,500 kWh, $30,859 value loss of $630 compared to imaginary 100% efficient inverter)
96% efficient: 168,000 kWh, $30,229 value (loss of $1,260)
80% efficient:
140,000 kWh, $25,191 value loss of $6,298
Notice the the reduced KWh between a 98% model and the 80% version