Prior to state-by-state enhanced building codes, most homes were not insulated. Many homeowners are not aware that they may have zero insulation in their walls. Keeping your heat in during the winter may be a loosing battle, keeping the summer heat out may be costing your hundreds of dollars in cooling bills.
Exterior wall insulation is important in both warm and cold climates in keeping the interior at a more constant state. R-Value is a measure of insulation’s ability to resist heat traveling through it. The higher the R-Value the better the thermal performance of the insulation.
Building codes vary by state, for example Michigan changed their building codes in 1970 to start insulating exterior walls, and have updated those codes to require even more R-value over the years. Texas changed their insulation codes in 1980, California in 1978.
Per EERE: Air leakage can account for a high percentage of heating and cooling bills in an especially leaky house, and homes built before 1980 often have little or no wall insulation. Given that walls can represent most of the building envelope area, ensuring that walls have proper levels of insulation is an essential part of any home energy retrofit. Energy retrofit projects should consider and address air sealing in walls and wall junctions to semi-conditioned or unconditioned adjacent spaces.
If the home was built prior to the 1930's it may not have a cavity wall for insulation. These homes built with single walls need special considerations when it comes to insulation. Some moderate climate areas like Florida and Hawaii still build single wall homes because the need for insulation is not as great.
DIY wall insulation can be difficult and hazardous unless you are up to date on all fire and building codes. Fire safety plays a big part in the project. Care needs to be taken when insulating around electrical fixtures, recessed light fixtures or any other heat-producing element that may be in the walls.
Snugg Home recommends using a local licensed contractor who is aware of all fire and building codes.
If you are replacing siding on a house, it's a perfect time to add insulation. Or existing siding can be temporarily removed in optimal areas for blown-in insulation - see photo. If your attic is unfinished, insulation can be blown into the walls from above - before you finish and insulate the attic.
Energy Star provides a climate map and insulation recommendations for each zone.
About Sandy Michaels
Sandy has regularly contributed to our blog and knowledge base with how to articles. She is extremely knowledgeable about the Snugg Pro platform.