This little device has been pumping along for over three months now. I have some data and observations about performance. Remember this is a 2.5 gal heater and only serves the kitchen and dishwasher, so not much volume of water. Here's a chart of data taken over the last month. It shows KWH and ounces of water removed per day. It also shows the basement temp which has been at 70F for most of the summer. but is now starting to drop, in January it will be down near 50F. The chart also shows a horizontal line representing the KWH that would be used when running with the resistance heater.
It uses about 60% of the electricity that it would use with resistance heat, not really great.
During the summer it also removes 30 ounzes of water per KWH. I have a good dehumidifier that removes 58 oz per KWH, so its about half as efficient as a good dehumidifier.
Where I live natural gas is less than half the cost of electricity for equal energy. I have a gas water heater which is probably about 85% efficient so in the summer I might save a little energy, but not much.
As the basement temp drops and the air gets drier this might not work well at all. But the resistance heater is in tact and I can easily switch back to that.
There are other benifits. First the temp is set at 100F, much lower than the main water heater. This temp is good for hand washing and rinsing dishes.
The biggest benifit is not pouring water down the drain while waiting for hot water to make it through 30 feet of 3/4 copper pipe.