To be ENERGY STAR qualified, products must meet specific energy efficiency levels that have been set
for three climate zones in Canada. In addition, all products must be certified for their energy efficiency
by an accredited agency.
Because the climate becomes progressively colder from Zone 1 to Zone 3, the levels are more stringent
for each successive zone. This means that models that qualify for Zone 3 also qualify for Zones 1 and 2.
Products are rated on either their U-factor or their Energy Rating (ER). The U-factor is a measure of the
rate of heat loss. The lower the number, the slower the heat loss. The ER is a formula that includes the
U-factor, air leakage and the benefit of potential solar gain. The higher the value, the higher the
potential annual energy savings. Products must also have an air leakage rate of ≤1.5 litres per second
per square metre of product area.