This is a pretty terrible deal for the homeowner. They're selling a call option that is $X in-the-money. This is worth that $X, plus a premium for the optionali

This is a pretty terrible deal for the homeowner. They're selling a call option that is $X in-the-money. This is worth that $X, plus a premium for the optionality involved. Then there's the counterparty risk, where you're obligated to a variable lump-sum expense in ten years at a valuation under the control of the entity you've contracted with (and based on the initial valuation, also under that control).