This R value frame assembly besides reducing heat losses, warms up the critical edge of glass region - dramatically reducing condensation. But just as important as Fibertherm's warmer edge, is its slimmer frame and resulting larger glass area. The larger glass area increases the total R value of windows because energy efficient glass insulates better then most frames. Increased free solar heating is another advantage of a larger glass area. These advantages minimizing heat loss and minimizing solar gain, add up to the highest Energy Ratings and consequently the lowest heating bills.
Every window maker has slightly different designs.
But no matter what you are considering, no matter what other sales people say, no window registered with Ontario Hydro has a better Rating than Thermotech's Fibertherm Windows. If you want to know more about Thermotech's Fibertherm Window system contact us at Thermotech Windows with your questions or comments.