I’m in a similar situation to you. Oil boiler with central air, and fan coil units that can be converted and run from heat pumps. I’d love to do solar and switch. $30k does not make sense from a repayment period perspective. Even $20k. I haven’t quoted it out (planning to do solar first), but sounds like there’s no rush for me either. I do my best to cut down on emissions for environmental reasons, but part of that means being selective about spending my money where it’s going to produce the most benefit. This does not sound like that place.