Excuse the newbie question: Should I finish my weatherization projects (insulating the roof and basement) before doing a Manual J and sizing a geo installation? background: I have a 3000 sq ft house in new hampshire and am keen to install geo hvac (at present, it has an oil-fed forced hot water furnace). Am planning to retrofit ducts and do a closed loop indirect water to air geo. One contractor did a back-of-the-envelope size estimate of 6 tons, and offered a general estimate of 40k for the well, ductwork, heat pump, and desuperheater. He has not had a manual J done yet, but will once I commit to the install. Another contractor offered to do a Manual J up front for $800. I don't want to waste their time or my money, and wonder whether I should wait to do the manual J until the envelope work is complete. As I mentioned, I am also planning to insulate the roof and basement this summer--which is a project because of vaulted ceilings. Thank you.
Do not pay $800 for a manual J! We are having a sale this week for $750! (cmon you were all thinking it) Seriously there is freeware on line there is the private license for hvac clc ($50). Mnual J has some fudge in it so it is not perfect but it can help you sort out the value of added insulation measures by pct of load reduction. Get it low enough and you can compare other heating options as well. j
