Once you have done all that can be done to eliminate convective heat loss in a building by caulking all cracks, sealing openings, weather-stripping doors and windows, then it is time to look at adding more insulation to the building and to the windows. Improving insulation in a house eliminates conductive heat loss. The amount of insulation that is required varies with the climate quite considerably. However, the recommended minimum is R-20 for walls and R-30 for ceilings except in the far south and west. Many houses simply do not have this much insulation.
Step One: Find Missing Insulation
The first area to insulate would be those areas that are not insulated. Often insulation is damaged or removed and not replaced when repairs are carried out or additions made to a building. The first step to adding insulation to a building is, therefore, a matter of finding the missed spots and getting these areas insulated.
Step Two: Add Insulation to the Attic
Once holes in the insulation have been taken care of, the next area to add insulation to is the attic. The majority of conductive heat is lost through the ceiling of a building in the winter. Likewise, during hot summer months, the majority of the outdoor heat is absorbed by the roof and comes into the dwelling through the ceiling. Except in a very mild climate, an attic is best served by adding enough insulation to bring the R value up to 30 or even 38. Fiberglass bats would need to be applied at a thickness of 13 inches in order to provide an R value of 38 and Vermiculite or Perlite would need to be blown in to a thickness of 18 inches to provide the same R value (Check with your supplier as different sources give different R values and required thicknesses for different materials.)
In order to decide whether an attic needs to have more insulation in it, measure the temperature in the attic on a cold winter’s night. If the temperature is more than 10 degrees warmer than the outdoor temperature, the attic needs more insulation.
Fiberglass bats or rolls are the least expensive form of insulation as they are very easy to install and need no special equipment. However, fiberglass is very unpleasant to deal with and provides a health hazard. Breathing fiberglass dust is very injurious, and once an attic is covered with fiberglass it is not wise or easy to use the attic space for any purpose.
Cellulose, Vermiculite, and Perlite are all loose fill type insulation. These are much more pleasant to deal with from a health and comfort point of view. If joist spaces are irregular, a blown in insulation such as this is very convenient and definitely the insulation of choice. You can rent a blowing machine, and blow in the insulation yourself to save money. The insulation needs to be blown in under the eaves and can be spread in the attic with a garden rake.
Step Three: Adding Insulation to Your Windows and Walls
Depending upon whether you have smaller windows and lots of wall space or larger windows and less wall space, you will want to add insulation to your walls or your windows first. Adding insulation to a window is usually much easier than adding insulation to a wall, so most likely you will want to find at least a temporary means of increasing the insulation to your windows.
Read How to Insulate Windows with Curtains or Other Window Treatments" and How to Get Your Drapes to Insulate Your Windows: The Importance of a Good Seal to see how ordinary drapes can be turned into effective window insulation.
