I don't know far into the future the payoff is, but it's getting closer at an increasing rate based on anecdotal evidence of the rising cost of heating fuels vs. electricity.
I also get a $15k deduction on the assessed value of my house for the life of the system, for property tax computation purposes.
And I get to keep my house at a comfortable temperature with little regard to the cost of doing so.
My wife and I built our house over the course of most of 2004. It will take a major personal or natural disaster to force us to leave, so I'm sure we'll be there celebrate the payoff date
