U-factor
Rate of heat transfer through the complete product; lower means better insulation.
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Glass & energy · 2 min read
How to read residential window energy results
Understand U-factor, solar heat gain and Energy Rating without treating one tested configuration as every product.
At a glance
SHGC
Fraction of solar heat admitted; the useful target depends on orientation and comfort goals.
Energy Rating
Canadian comparative value combining heat loss, solar gain and air leakage.
The useful decision
Understand U-factor, solar heat gain and Energy Rating without treating one tested configuration as every product.
Three different measures
U-factor describes heat transfer; lower is generally more insulating. Product SHGC describes admitted solar heat; the useful target depends on orientation, shading and comfort goals. Energy Rating combines several factors for a reference condition.
Configuration matters
Operation, size, glass make-up, coatings, spacer and grille details can change the reported result. Morrison’s QAI listings identify specific model and glass codes.
Use the current listing
The website provides planning ranges, not an order specification. Match the exact proposed model code to current documentation and local requirements before ordering.
Bring this to the conversation
Project checklist
- Match the exact model, operator and tested size or configuration.
- Check the complete glass code, coating, spacer and pane count.
- Compare units before comparing numbers.
- Confirm current qualification and project requirements before ordering.
Avoid assumptions
Questions worth answering
- Is winter heat retention or summer solar control the priority?
- Does the value apply to this exact configuration?
- How do orientation and exterior shading affect the choice?
Continue with trusted information
Useful resources
Before final selection
Open the energy centre
Confirm the exact product, current documentation, applicable codes and project conditions with the appropriate project professionals and Morrison team.
