BFRC Window and Door Energy Ratings for Comparing Energy Efficiency in Glazing

The BFRC rainbow is the most trusted rating system for proving window and door energy performance in the UK. That's because it's the most complete.

Instead of just rating heat loss, it provides expert and independent assessment of the product’s complete energy performance - heat loss, solar gain, AND air leakage - giving you the full picture to make a fully informed decision.

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Then add a trickle vent and nullify the rating?