[NiHaoMike]

Those Daikins are just one example of a conventional (air source) heat pump.

So that's just over $6 per month service charge, not too bad. But the page says that for a water heater, going with gas (as opposed to conventional electric) is only a 40% savings. Contrast that to a heat pump water heater where a well designed unit easily uses less than half the energy, a really good one less than a third.

I'm going to guess that gas isn't actually cheap in your area, but they use obscure units to make it look like it is.