Is the massive change in my quote worth it? General thoughts?

Location is upstate NY. I’ve been working with an installer for a while to nail down what I’m going to do here at the house. We finally finished our addition and roof replacement. We’ve converted a lot of appliances to electric and the addition uses all electric heat (baseboard and floor). We also want to have battery back-up instead of a whole house generator. We really only need a few critical circuits, but it might be nice to have the whole house for our many frequent short outages. This most recent quote is for a much larger system but seems disproportionately costly given the size increase. He attributes some of that to the fee for the 0% loan, what are your thoughts?

QUOTE

17kW DC solar array

Hanwha G10+ 400W modules Black

Sol-Ark 15K whole house backup hybrid inverter

Tigo Power optimizers

SL-14 Energy load management panel (will turn off unneeded loads to keep batteries lasting longer)

20kW of lifepo4 battery bank. (4) 5kW modules in a cabinet – further expandable at $2250 per 5kW pack

25 year labor and parts warranty on modules

25 year labor on whole system

10 year parts warranty on Sol-Ark equipment (most likely to last much longer)

This setup will allow your whole Main Service panel to be backed up. However loads such as electric heaters upstairs etc can be programmed to turn off automatically when battery backup mode is engaged.

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Gross: $79,140.91

NYSERDA grant: $8,500

Bridge loan: $~23,350

Finance 15yr 0%: $47,290.91

Monthly payment loan: $262.72

Energy offset annual 16,000-17,000kWh