Electric Rates (where you live)

I used that calculator to extrapolate to the rest of the year.

Just putting in the array size and orientation, taking the default derating factor without shading, the June and July production was 97% of what this calculator predicted.

A photographic series of panel shading through the day finds that it is significantly better up there than down here at the windows where I mentally swagged a shade derating factor. As the seasonal sun angle falls, that shading won't change much for about one more month, but then will start changing rapidly sometime around the equinox.

If economic payback time was important, I'd have performed a true site survey to predict output. But this is something I've long wanted. The pre-summer installation window was short, the professional installers had a major backlog, my summer calendar was already quite full, and I didn't want to postpone everything until the next open block of time after the major summer production season was over. So I jumped on it without a survey. No regrets.

 

Recovery time?

All the units I considered have backup resistance heat, and can be switched to traditional electric mode for high demand situations. Most have a setting that does this temporarily (e.g. 48 hours), then automatically revert to hybrid (mixed) or heat pump mode.

Mine came with a default mixed mode. For maximum economy, I changed that to heat pump only for the summer, it will need to go back to hybrid for the winter. A reheat cycle, triggered when the lower thermostat falls 20F below the setpoint, is taking about 2 hours in the current warm weather.

Locally, incentives are available full time, and sales are frequent. For my 2-person household burning 9kWh/day on the old heater, this adds up to considerable conservation. But for a single person getting by on a 20 gallon tank, the savings may well not be enough to justify the cost.

 

I currently have a 40 gallon electric water heater. It's about 7 years old, and within a few more years will be getting "old". All of my faucets are at most 2.25 GPM with most 1.75 GPM flow, including shower heads. In the summer, I put my shower head on the setting that results in only the outer half of deals used and typically take cooler showers. I'm not sure what I'm spending energy wise per day on the water heater, but I know that these aren't very efficient. I'd switch to an equivalent sized of the heat pump hybrid ones, if I make the switch before I convert from heating oil to propane for the furnace. If I do the furnace first, it's propane tankless for the water heater for me.

 

Done. It was energized last night, and began producing this morning. Though only barely due to the rainy weather. The high production season is mostly over, but I should still get some occasional net-zero days in the coming month.

 

In answer to the original question:

LIPA (Long Island Power Authority) - Rate 180 - Residential, General Use - from http://www.lipower.org/pdfs/account/rates_resi.pdf

Time Period June 1 - Sept. 30 | Oct. 1 - May 31
Service Charge: Standard Rate $0.3600 | $0.3600
Energy Charge: (per kWh)
First 250 kWh $0.0857 | $0.0857
Excess 250 kWh $0.0975 | $0.0787

PS. My PiP is still a virgin...

 

What a useless pdf. Leave it to LIPA to make a simple question completely opaque.
Here is a sample bill from LIPA. The marginal energy cost including taxes is about 19 cents/kWh