Thanks, I just modified my spreadsheet predicting 4% annual return for the next 15 years (although the article I could find with Bogle's prediction is a decade

Thanks, I just modified my spreadsheet predicting 4% annual return for the next 15 years (although the article I could find with Bogle's prediction is a decade of 4% returns) and then 7% thereafter. The 30Y loan still comes out ahead, but very slightly (less than $3000 advantage on about $2M expected value of the portfolio). Such is the time value of money. Agree with you about solar panels (and other efficiency upgrades) - my initial remodeling plans are improving sealing, insulation, and upgrading to a more efficient furnace. Already got the smart thermostat!