Ener Can defines an ER rating as a unit of measure derived from a formula that balances the heat loss (U-Factor), air leakage loss and the potential passive solar gain of a product.
* The ER formula is found is the CSA A440.2
What does this mean to us? An ER rating correlates to a part of the country’s (see map to the right) zones. Colder zones require more of the Sun’s Heat so they require a higher ER rating.
- Zone A – min. ER rating 21
- Zone B – min. ER rating 25
- Zone C – min. ER rating 29
- Zone D – min. ER rating 34
*see map to the right for the zones
R- Value what is it?
The R- Value is a measure of resistance to heat flow from the warm side of window to the cold side of the window. A higher R- Value is better for the reduction of heat loss from the heated space.
What does this mean to us? This means that higher R-value windows conduct less heat transfer, which means it retains the heat inside better, kind of acting like the insulation in the walls of your house.
How is this useful to me?
If you want to take advantage of the free energy from the Sun choose Cardinal LoE 180 glass as this glass is well suited for cold weather climates but also provides an excellent passive solar application which means you gain more of the sun’s heat.
*LoE 180 is compliant for Canadian Energy Star Zones A, B, C and D
If you want the maximum protection from the Sun choose Cardinal LoE 366 as this glass reduces Heat Gain by 64% compared to ordinary glass and has a low R factor (resistance to heat) of 4.17 (lower is better) than ordinary glass. The Cardinal LoE 366 glass blocks as much as 95% of the Sun’s UV rays; while reflecting 98% of Radiant heat and cold back into your home which means it is the ultimate performance glass.
CONTENT PROVIDED BY: vinylbilt windows & doors