The most energy efficient door for your home is not always the one with the highest insulation value. Factors such as glass inserts, the amount of sunlight the door receives, and your home's overall design can all affect performance.

For the best results, consult a door professional or consider having a home energy assessment. This ensures you choose a door that balances insulation, style, and comfort for your specific home.

An important difference from Windows

• Unlike windows, hinged exterior doors are not rated under the Energy Rating — ER — system. 
• ER is a composite metric that includes solar heat gain — a meaningful factor for windows, but not the primary consideration for most opaque doors.
• For hinged doors, U-factor is the standard metric used for comparison and certification.
• ENERGY STAR® certification requires a maximum U-factor of 1.22 W/m²·K for doors in Canada’s Zone C, which covers most of Manitoba. 
• The lower the U-factor, the better the door resists heat loss. High-performance insulated doors can achieve U-factors as low as 0.8 W/m²·K.

Whole-assembly vs. slab-only ratings

• As with windows, door manufacturers sometimes quote the R-value or U-factor of the door slab or core only — not the full assembly, including the frame and glass.
• Always ask for the whole-assembly U-factor when comparing products, and confirm it is the figure used for ENERGY STAR® certification rather than a centre-of-panel measurement.

Look for certification labels from trusted organizations like the Canadian Standards Association — CSA or the National Fenestration Rating Council — NFRC. These labels confirm that the door has been tested and rated for air leakage and overall energy performance. 

For doors with small decorative inserts, VT is a minor consideration — the glazed area is too small to meaningfully affect interior light levels.

For half-lite and full-lite doors, VT becomes more significant — particularly in north-facing entries, where the door may be the primary source of daylight for the foyer.

If natural light is a priority, ask your supplier for the VT figure for the specific glazing product in the door you are considering. A VT of 0.50 or higher is generally considered good for residential applications.

Be cautious of heavily tinted or reflective glass inserts marketed for privacy — these typically have lower VT and may make interior spaces noticeably darker.

If privacy glass is important, ask how the treatment affects VT. Frosted, tinted, patterned, or reflective glass may improve privacy, while also reducing natural light. 

No matter how well-insulated your door is, a poorly installed or low-quality threshold can lead to major comfort and energy issues. Make sure your threshold is level, properly sealed, and designed to work with your door. 

If anyone in your household uses a wheelchair, walker, or mobility scooter, discuss threshold height and profile with your door supplier before purchasing.

An automatic door bottom paired with a flat threshold is often the best combination of performance and accessibility.