Need advice on renovating 60 year old home in Maryland.

[Dave A.]

Just use half as much, you get almost twice the r-value per board foot, from what I'm reading.

Edit: And I'm just saying what I'd do. You can do what you want.

And again, I'd suggest trying to sell the a/c unit and replace it with a heat pump, if you're serious about saving money on heating.

 

[NRGarrott]

Sorry If I came off as short with you Dave. I looked at the cost of insulating with closed cell, and even using half as much, it was just priced too high.

 

[Dave A.]

Haven't really priced it myself. Was basing it on this http://www.greenbuildingadvisor.com/green-basics/spray-foam-insulation-open-and-closed-cell

which may not be valid any longer. But if that's the case and closed cell is just too expensive, I'd consider other alternatives. Even before Floydian's message and link, just didn't have a good feel for open cell sprayed on surfaces abutting the exterior. I have the sense it's okay for sound insulation on interior surfaces, but otherwise...

Edit: not saying not to do it, if you feel it's the best alternative for you at present, just that it's not as good a product as the closed cell. And of course, given that it may only be temporary, if you tear it down and rebuild, that makes the negatives less important.

Edit: Also about the heating. Am not suggesting replacing the oil furnace but rather using it as the backup for the heat pump (rather than have elec resistance as the normal heat pump back up). This also covers you in the (slim) event that oil prices drop in the future. But whether you do it or not, you should investigate the costs and cost savings of a heat pump. And if you can do the work yourself, the payback should be pretty quick.