This is very much not the case, according to Eric Corey Freed, director of sustainability at Cannon Design. In fact, installing solar panels is probably the last thing many of his clients will wind up doing in their zero energy quest. The first, most important element in the structure to consider is…(surprise!) the insulation.
How insulation works
“The act of heating and cooling consumes between 50% to 70% of the total energy used in your building,” explains Freed.
One key reason people pay so much to keep a building a consistent temperature is that insufficient insulation allows too much air from outside — either hot or cool — to seep inside. This is what triggers the constant need of an HVAC system to keep the interior of the building a certain temperature. The better your walls are insulated, the less the temperature fluctuates.
Quantifying insulation ability
The ability of a material to insulate is measured by what is called R-value. The higher the R-value a material has, the greater its insulating ability.
“Most of the older existing homes in this country are poorly insulated,” says Freed. “There are over 50 million underinsulated homes in the United States, wasting the equivalent of about 2 million barrels of oil every day in lost energy.”
Most buildings have the bare minimum: an R-13 in their walls and R-19 in their roofs. R-60 is considered a super-insulated and high-performance building. After attaining an R-value of 60, Freed will stop adding more insulation because he’s seen anything beyond that provides diminishing returns.
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