First, any radiant barrier must have at least a 3/4" air space immediately in front of its shiny surface or there won't be any infra-red energy to reflect. A radiant barrier would save very little energy in a wall system in New England so it's generally not considered cost effective. One can be moderately effective in a roof system but the back side of foam sprayed into rafter cavities isn't going to be very hot so there would be little infra-red energy emitted from it.

I am in south Louisiana. energy_rater_la, I have no problem with overfilling the walls. I need all the R I can get, and even though I give up R=1 for a 1/2" of air, I get R=1.9 for 1.2" of spray foam, and at $.16/in-ft^2, it still marginally makes sense. For the roof, as I will generally have 2x10 rafters (i.e., 9-1/4" deep), I do not need to have insulation all the way there (the optimal level from an overall cost benefits analysis is at 8".) energy_rater_la, are you saying that I do not have a problem with having some space between the foam and the ceiling sheet rock, unlike for the walls? It would not matter much if I did go all the way to 9-1/4", although I would be paying a little more for the insulation than I would get back in reduced energy costs (using my analysis of the cost of financing and energy cost increase and expected life), as well as not taking advantage of the air space R (value of 1). As for exterior insulation, in general, the costs of the material is so high, that once the wall is at R-12 (net), the total costs of the material and labor are higher than the reduction in energy costs. Actually the cost of material alone is OK, but the extra cost of labor pushes it into being too expensive. There is a new combined structural and insulation sheathing (Dow Styrofoam SIS?), but the material cost is even higher, and it only almost makes financial sense, but with the problems of "this is new, and how good is this going to hold up". However, since the east and west walls get more insolation (and therefore more heat gain), the numbers begin to work out for exterior insulation, and there is the added benefit that the local heat gain is less, which allows those rooms to have the same heat gain as the rooms with non-insolated walls, thereby allowing a more constant indoor environment. I will be putting in an extra 2" of insulation there (which makes integrating with windows easy as all manufacturers make jambs for 6" walls.) This leaves the question of what exact type of exterior insulation should I get. There are so many different types out there - this type of foam, that type of foam, fiberglass, etc. And the idea of vapor and water barriers, foil radiant barrier, with the open cell insulation has me very confused. Fortunately, the price per R is about the same, so I don't have to make a decision based on relative price, but only on what is proper. Here are some of the brands I have researched: ProPink Foamular R-Max R-Tech Which of these is better for my situation? Are there any others I should consider? Thanx again

flex in a crawl...sigh the things we do... you don't get into specifics about the audit and I've learned not to expect much from a lot of 'audits'. but... ducts leak.flex less than hard pipe. where they connect to the plenum @ start collar where they terminate at supply box and where supply box connects to floor. just by removing a supply grill inside the house you can see the poorly sealed cut. before you spray foam..mastic seal these areas I listed above. paint on mastic or mastic tape like hardcast brand #1402 duct leakage is high in existing house. sealing the ducts with acca ul approved products should be done prior to foam don't let foam company sell you duct sealing with foam foam is not a duct sealant. not approved & over time fails quickly. if ducts are strapped in between floor joists..how will foam company get foam to floors? better take a look under there and see if ducts are strapped or loose or lying on the ground. (ducts shouldnt lie on the ground) do any duct sealing first...its a pita to dig out foam to work with ducts...been there done that. I'd use closed cell. if you use open cell then a vapor barrier has to be installed on the face of the open cell once install is complete. unless you have a perfect vapor barrier on the ground...that is still perfect after foam install. while closed cell will trap moisture it is the way that it is installed that will make the difference. install is 2-3" of closed cell in between floor joists. the joists themselves are not encapsulated in foam (directly opposite from unvented attics..different product different needs = different install) where the foam meets the floor joist is where the future leaks will exit. if you go under a house that has had closed cell installed you will see that in a couple of years the foam seperates a bit from the joists. closed cell is rigid when dried and doesn't expand and contract like open cell. this seperation helps to aid exit of water from leaks. did the audit cover duct leakage and how to address? what shape are the ducts in currently? are they strapped up or not? your system is in the house in a closet? shop your foam companies wisely. ask for customers names that have had similar installs and speak with them. as for as offgassing..all foams offgas. but it is outside of the living space and shoudn't be a problem as long as there are no gaps for the foam to enter the house or the ductwork. you may want to spend the night somewhere else if you worry that it will make you ill. any plumbing work in the future will have to be re-foamed once work is complete. usually cans of great stuff can be used to seal these smallish areas. if not the foam company has a bigger can of foam that will cover most of these larger areas. best of luck

I am skeptical of what 1/4" of foam would do for a house with a lot of openings. I am also skeptical of any bubble insulation that claims to be a radiant barrier and provide an R value of 6. These seem like odd choices. What climate are you in and what is the exterior cladding?