I don't want to hijack your thread, but I have the exact opposite question! We are thinking of air krete foam in our existing walls and blown in cellulose in the attic. Is the air krete (a cement based foam) much better than dense pack cellulose in the walls? It's about $1200 more. Any help with insulating info would be greatly appreciated. We currently have next to none in both attic and walls. Thanks.

Dense packed cellulose for walls... Could also use mineral wool (roxul), but its expensive.

I'm getting ready to have more insulation added to my attic. It has probably R11 cellulose in there right now, which isn't nearly enough. I've done a lot of research on the pros and cons of cellulose vs fiberglass, and I'm going with cellulose. Independent testing has indicated that, for natural settling, cellulose will not pack down to the point where its R value is diminished. Also, if you're in an area where it gets extremely cold, fiberglass will apparently lose R value effectiveness the colder it gets, where cellulose is a lot more resistant. Fiberglass is, of course, a LOT more fire resistant, but cellulose isn't particularly flammable, either, because of the chemicals used to treat it. Ease of installation goes hands down to cellulose over fiberglass batts. Blown in fiberglass is about as easy to install as cellulose. Overall cost is, I believe, roughly comparable between the two on a square foot basis. So, I'm going with cellulose. Ultimately, though, I think the battle between the two types is far less important than simply getting enough insulation and having it installed properly.

Judy, You are obviously doing a good deal of research about your house before making plans, which is a very good idea. I am attaching a link to the entire Preservation Brief series, where you will find a wide range of topics covered, including the most up-to-date editions (available, now, for free on the net). I have a couple of comments about your proposed plans. For your attic I would suggest adding additonal layers of fiberglass on the outside thirds of the attic floor. You can just lay it right over what you have there. (You may need to poke around a bit to discover where you can safely walk on the joists to get the material all the way out to the edge.) For the middle third, I would pull the floor, and insulate that cavity. It's OK to use a combination of materials. In my plastered house I have a thin layer of fiberglass, followed by as much high R-value foam sheets as will fit in order to get the highest R-value in the space available, without putting undue pressure on the plaster or squashing material under the flooring. In your 75- year old house you probably have balloon framing which is easier to blow in insulation than some other type of framing. But blown in material may present problems due to lack of a vapor barier, and if you follow through on your plan to add vinyl siding, that may exacerbate the problem. If your wood siding is still sound, you could have it scraped and sanded and repainted. Vinyl siding inevitably results in a change (and not for the better in most cases) of the details of your houses' exterior appearance. You could also have the siding removed, along with underlayers of sheathing, etc. and insulate (and add air and moisture barriers) before reinstalling the cleaned-up siding, though this is big job. I would opt for just scraping and repainting. As for your proposed new windows, well, I wouldn't do that either, if your existing windows aren't completely rotten. In most instances wooden windows can be vastly improved energy-wise by rehabilitation, instead of simply replacing them. Unless you are extremely lucky or prepared to devote enormous sums to having exact replicas made, the new windows will be, at best, a compromise stylistically. The loss of both the siding, trim and window details will change your houses' appearance significantly. In this year of energy-cost worry, it is hard not to spring for any and all improvements, but you can make a big dent in your energy-use by adding additional insulation to your attic, good weatherstripping around doors, diligent caulking all over the house, perhaps even temporary interior storm windows, etc. These relatively small-scale jobs will give considerable payback in both energy costs saved and increased comfort. And they will buy you time to assess the big picture and find solutions that do not result in so much loss of your house's historic character. With old houses, I find it's really important to go as far as you can in adding energy efficiency, but not worry much if you can't achieve R-49 in your attic. That's the standard for new constructin and in most old buildings not a realistic goal. Good luck with your house! Molly~ Here is a link that might be useful: Home page for Preservation Brief series