I have whole house solar that we own as opposed to lease.
But I have neighbors who are doing solar lease, not sure if it's as long as 20yrs but it's much less costly for their situation, than paying to have them installed. It depends on how long they think they'll live there, I suppose.
With what we paid to own them, it will take us 5yrs for the cost to payoff vs. what our average electric bills were previously, but we plan on keeping the house at least another 30+ yrs. so it makes sense for us.
You need to ask the seller for records of their electrical consumption for 1-2yrs prior to the installation of the solar panels & then compare that to the cost of the solar lease monthly, I'm sure it's going to be a savings for any new owner.
Emily S. Knell
Realtor Since 1996
Realty ONE Group