Updating house insulation
The most common insulation retrofit for old houses is loose fill because it can reach places where it's difficult to install other insulation. The National Park Service (NPS) recommends using loose-fill cellulose (recycled newspaper) insulation that has been treated only with borates as a fire retardant, rather than insulation treated with ammonium or aluminum sulfate."Insulation treated with sulfates reacts with moisture forming sulfuric acid, which can cause damage to most metals (including copper plumbing and wiring), stone, brick, and wood.Asbestos was a common component of heating system insulation by 1910, and by the 1930s it was also being added to some building insulation products.If you suspect your home has insulation containing asbestos, a known carcinogen, have the material tested.I grew up in an 1880 Queen Anne in Newton, Massachusetts—a balloon-framed house with very little insulation. When I complained that the house was too cold, my father would simply reply, "Put a sweater on."There's better advice available than my father dished out.Today there are loads of energy-saving, cost-effective thermal insulating options on the market, and choosing what is appropriate for your house depends on several factors.The higher the R-value the better the material insulates.
Cotton batting treated with borates is a good choice for an old-house retrofit.
Other areas to consider are air leaks though cracks around windows, ducts, electrical outlets, and recessed lighting.
Note that the primary site of heat loss is through the top of the house.
Borates are physically and chemically compatible with many existing old-house materials," says NPS Preservation Brief #3.
An insulation's R-value—the material's thermal resistance or resistance to heat flow—depends on what region of the country you live in and what part of the house you are insulating.