energy-efficient homes, Zero energy homes & insulation Levels

House Insulation using wood framingInsulation is the most critical factor in energy efficient single-family homes, in many climates. The levels of your home’s comfort, the type and the size of your heating and cooling equipment or your energy bills … all depend largely on insulation levels.

Do not try to save money by installing low or moderate levels of insulation in your new home.

Take some time, and plan it with your home designer, architect, builder… It’s worth spending money in insulation and air-sealing.

Consider levels of insulation above those recommended by common building codes, which fall very short of the best. If possible, consider standards similar or very close to those of Zero Energy Buildings and Passive Houses - those that inspire the approach suggested below.

Home Insulation all over the home boundaryAll the elements of your home’s shell – walls, attic and ceiling, floors… - should be carefully insulated.

Pay special attention to ducts, pipes, edges, corners, connections… Pay attention to the wall, ceiling and floor framing elements. They too should be carefully insulated. Avoid any thermal bridge through them.  

Building a very-enerrgy efficient home is a lifetime opportunity to save many hundreds of dollars per year in energy. Do it right the first time. Doing it later will be a lot more expensive or impossible.

Super-insulated homes

The German standards for super-insulated homes (Passive Solar Houses) are notably strict, but they are a good benchmark for those who aim to have very small heating and cooling systems, and reduce energy consumption to a minimum. They are mostly valid for cold and very cold climates.

See: Recommended insulation levels

Build a very air-tight home

New homes, in cold climates, should also be carefully air sealed before any insulation work. Attics, floors and walls should be thoroughly air-sealed.

Caulk and foam all gaps, openings, cracks and holes. That's critical to keep warm air in cold air out. Pay special attention to corners, hedges, intersections and piping holes. Do not forget gaps around electrical boxes and outlets; or gaps around fans and channels for drain-pipes and wiring. All air pathways should be caulked or foamed.

Pay extreme attention to details. Results will depend on it.  Your contractor should carry out tests to find out the air-tightness of the house.

See: Air Sealing for Energy Savings

Attic and ceiling insulation

nsulate your attic to levels between R-50 and R-60 (Metric System: R-8,5 and R-10).

If necessary, consider foam insulation. Prefer a flat ceiling. It poses fewer problems, is easier to insulate, and reduces the volume of air to be heated or cooled.

See: Attic Insulation


Consider high levels of wall insulation: R-30 (Metric system: R-5) or more, in cold climates. These levels are much higher than the values required by energy codes, but they are the ideal for low-energy buildings, in cold climates. Pay attention to thermal bridging.

Stud wall cavity insulation is not enough. Heat loss through studs has a big impact. To achieve high levels of wall insulation in wood and steel frame homes, with cavity insulation, walls should have 2 to 4 inches of foam insulation all over their outside (in some cases the inside).

Exterior-wall corners, intersections and other weak-thermal areas should benefit from increased protection and attention.

Walls in hot and moderate climates need significantly smaller amounts of insulation.

See: Wall insulation guide for energy savings

Foundations and floors

Slab-on-grnde foundations are much affordable and less prone to problems that the basement and crawlspace design. Once a choice for hot and moderate climates, concrete slab-on-grade foundations are becoming increasingly common in cold climates. See, for instance Toolbase Frost Protected for Shallow Foundations.

See: Floors & Energy Savings

Basements and crawlspace insulation

See: Basements Guide & Energy Efficiency




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