Insulation, Radiant and Vapor Barriers - Insulation (Adding Insulation for Energy Conservation)

I live in a home built in the 70's. It's about 1800 sq. ft. I have a gas furnace (ch/a) for heat, and in the winter my gas bills exceed $300 on the cold months. I have one layer of fiberglass insulation in the attic and some celulose sprayed on top of that. I might have 8" total. Would I be money ahead to add insulation to the attic? If so, what kind (fiberglass or celulose)? Also, there is no insulation between the floor joists. Same there? Add some? I'm just looking to try to save on energy costs. Any ideas?


P.S. - Will spraying more celulose cause my sheetrock ceiling to sag? I don't want to overload it...

If your bills are over $300/mo in Arkasas, you definitely need more insulation AND attention to air infiltration. My 1400 sf (two story, two exterior walls exposed)townhouse in Minnesota has never been over $100/mo for heating and I really don't have an excessive amount of insulation in the attic (original 1980-85 construction).

You can safely blow in more cellulose insulation. When it comes to type of insulation, a number of active members will voice up for cellulose.

If you have a crawl space and not insulation beteer the floor joist, you could use insulation there also.

Dick

I suspect another cause for my high gas bill is my furnace. I bought the house from my parents, and I can remember helping my uncle install it (used) in the early 90's. I know it needs updating, but that's a price tag I can't swing right now. For now, adding insulation which I assume I need, will have to do.

Anybody else? I'd like to hear from more people who know more about this than I do. Input?