If anyone is still reading this thread, my mom has been suffering for years with blown in cellulose insulation finding its way into her single story house. The HVAC system is in the attic. A fine film of insulation covers every horizontal surface in her house and after 2-3 weeks of foregoing her weekly dusting ritual, you can dust a surface with your hand and have a good amount to visually inspect. She's been there since the house was new, nearly 15 years, and the HVAC company who installed the unit (along with the builder) when it was new have been back countless times to try and figure out the problem. Everything that can be sealed has been sealed. There are a number of pocket doors in the house that were the latest suspects, but even after sealing the tops of those the dust continues. She's had the "dust" analyzed to be sure and it is in fact the same insulation as is in the attic. She lives in South Texas and is to the point now that she's considering having the entire mess vacuumed out of the attic and replaced with batts. It seems completely impossible but I've seen it with my own eyes. If anyone else has had a similar issue and solved it, I'd love to hear about it!!

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

Hey appletnc. fire hazard with old wire a yes. I checked with my fire department as well. Replace old wire before going down walls. I did blow insulation myself in my 100 yr house down the walls.I did it upstairs and down stairs and in the ceiling. I never did it before, but it was a little messy. I only drilled 1 hole at the top not at bottom. I don't know why they said put one at bottom. I had a guy whose done it many times give me some advise. He never mentioned to do that. I did take off the siding instead of doing drywall. I tried one room inside the house and it took me awhile to get all those holes looking smooth again once I patched them. I ordered the plugs from lowes. I filled the cavity. Put in the plug and back on with the siding. All the mess stayed out side.. It made the world of diff. down stairs. Upstairs it helped some, but i think my heating unit is to small. Ps. It was much quicker doing it from outside than inside. If you compare to cutting holes in walls, plugging, remud, sand , remud, sand, remud , sand and paint. Verses take siding off, cut holes ,plug, put siding back on. No sheet rock dust or insulation in house. Hope this helps.

Moisture sensitive insulation is not appropriate for basements unless it is separated by a non moisture sensitive insulation. Closed cell insulation, which I have installed when the budget provides for it, is fine as long as it is protected by an approved thermal barrier. However, it's not a good choice for a retrofit unless you plan to be out of the home for at least a day due to the fumes. Also, there is risk if the applicator is not an experienced and trained person. This is no place for bargain-hunting. Extruded polystyrene followed by wood framing. A less expensive alternative would be sheets of extruded polystyrene affixed to the foundation wall followed by framing filled with fibreglass, rockwool or cellulose, all protected by an approved thermal barrier, typically drywall.