The time is already here. Anyone can now buy panels at ~$0.50 per watt, from Alibaba. To power a 10,000 watt home costs ~$5,000 in panels. Add $1,000 for an inverter and misc, add another $4,000 for installation labor (I'd pay ~$1,000), so for $6,000 to~$10,000 in total costs one eliminate their electric bill. That's a payback of ~3 to ~4 years. A 3x to ~4x revenue multiple seems like a cheap price to pay for an income producing/saving asset.

http://www.alibaba.com/showroom/price-per-watt-monocrystalli...