[woodbutcher1963]

“my payback for the solar stuff is about 7 to 8 years,”

Is this calculation based on the efficiency of your solar panels when they were brand new or over time?
My understanding(correct me if I am wrong) is that the companies selling the panels typically quote you a payoff based on the efficiency of the panels when they are brand new. Don’t the panels lose their ability to generate electricity over time? How long before they need to be replaced? Do they need to be cleaned? What happens IF the state changes the amount that the utility will buy your kilowatts from you? This happened in Nevada.

The reason I ask is that my daughter is considering having solar panels installed on their property in NH.

[Dad was my hero]

The calculation is mine based on the "proposed" and then the actual savings in kW hours. The first person who showed up just wanted to put a 10kW system on my roof and couldn't tell me if it would address all my electricity use. The next guy came in and wanted to "discuss" my electricity use and attack it from a point by point discussion. So I bought a solar assisted heat pump (my heat pump was getting old anyway) and this one has external tubes with more coolant and then he added a solar water heater at the same time and I waited to see my next bill. Both cut my cooling (I'm in FL) by just over 60% immediately.

Then in January the solar panels went on the roof. I only needed a 5kW system and he guaranteed me that my total usage would be $0 for the year or he'd pay me the difference. Well he was pretty close. My years' use was barely what I would pay in a month.

The panels supposedly have a life expectancy of 25 years but I was told that that can be extended considerably if you periodically clean them so every year I clean them (soapy water, hose and squeegee). Whatever electricity I produce goes into my house for use first. What is excess goes into the power grid and if I produce more than I use for a month I have a credit on my bill that will be applied to next month's bill. To my understanding only if I over produce for a year will they actually send me any money but that hasn't happened yet, the most I've been at 0 has been 4 months in a row.

I have no idea what would happen if the state changes the reimbursement but I doubt it will affect me much since I don't count on the thought I will over produce all the time. I produce just below what I use for a year so I still have to pay the electric company.

I also made other changes (because I'm cheap, not because of some "belief" in global warming or saving the planet) so I added insulation to my ceiling crawl space, put in impact (hurricane) windows (high efficiency), changed out my pool pump to a multi stage pump and changed out my lighting to LEDs and I did those things before I went to the solar. I save between $3,000 and $4,000 a year depending on the cost of electricity.