The project featured in this video will be a window replacement and insulation retrofit for an older Bozeman home. We will be improving the energy efficiency of the home by replacing siding, adding exterior insulation, and upgrading the windows
New exterior insulation
After removing the old cement shingle siding, and before installing the new siding, we will be wrapping the entire exterior wall surface of the house with a layer of half inch thick high density rigid insulation.
The benefit of the layer of rigid insulation will be to reduce thermal bridging that occurs through the exterior wall framing.
A thermal bridge occurs when heat or cold is conducted through exterior wall framing materials. Typical insulated wall cavities allow limited energy transfer. The problem is that the insulation on either side of a wall stud is of little help in preventing heat loss or gain due to thermal bridging. A thermal break of rigid foam placed in the wall assembly will greatly reduce the flow of thermal energy between conductive materials.
Our insulation layer also acts to stop exterior air infiltration. We want to eliminate air infiltration, but we don’t want to trap water vapor. We have chosen this expanded polystyrene insulation because of its water vapor permeability. This material has a perforated foil face on the inside and a water resistant face on the outside. The ability for an exterior wall to breath is important.
New energy efficient windows
The second part of this energy efficiency retrofit is window replacement. The existing windows were breaking down, leaking and very energy inefficient.
In older homes, windows are often one of the largest sources of unwanted energy transfer. Older windows typically lose or gain heat through conduction, radiation, convection, and air leakage. To minimize this type of energy loss we will install window replacement units that are energy star rated and designed for optimum thermal performance. A major energy saving component of our new window replacement units is the presence of a low E coating.
In a cold climate we welcome the sun’s heat and light. And once we capture the heat, we don’t want to give it up. A low-e coating is a microscopically thin, virtually invisible, metal or metallic oxide layer deposited on a glazing surface. The coating reflects heat back into the home during cold weather and back to the outdoors during warm weather. This effect increases the insulating value of the
The wall insulation detail and the new energy efficient windows will make a dramatic difference in this homes comfort level in both winter and summer. Not only will this home be more comfortable, but the energy savings for heating should significantly reduce winter time utility bills.