Solar Heat Gain Coefficient, or SHGC, describes solar heat gain through a window. A lower value can help limit unwanted solar heat, but it should be considered alongside daylight, shading and the room's use. There is no single shopping number that answers every question for a Mandeville home. [6]
Before requesting an upgrade, describe what you notice. A west-facing living room that becomes uncomfortable late in the day presents a different discussion from a shaded bedroom with worn seals.
Start with a room-by-room inventory
Record when each room feels uncomfortable, which windows receive direct sun and what shading is present. Photos taken at the problem time can make the conversation more concrete.
Include the owner's preferences. Some people prioritize bright interiors. Others want to control glare. The selected package should account for both the performance goals and how the room should feel.
Bring these observations
- Room and approximate window orientation.
- Time of day when the concern occurs.
- Exterior shading and interior window coverings.
- Desired balance of daylight and solar control.
- Other issues, such as drafts or difficult operation.
Read the complete energy label
| Label item | What it helps you discuss |
|---|---|
| U-factor | Heat transfer through the product |
| SHGC | Solar heat admitted by the product |
| Visible transmittance | The amount of visible light transmitted |
| Product identification | Whether the data matches the quoted configuration |
Use the actual whole-product information. A center-of-glass statement or a coating name alone may not describe the complete window being quoted. The NFRC directory can help identify documented configurations. [8]
Keep comparison scopes consistent
Ask both providers to identify the glass package in writing. Note any differences in frame type, operating style and dimensions. An apparent energy improvement may come with a different appearance or specification that needs to be considered.
A product with lower SHGC does not automatically solve air leakage or a damaged installation. If drafts are part of the problem, assess their source instead of treating the glass package as the entire answer.
Coordinate the glass with the architecture
When replacing only part of an elevation, ask how the new glazing will look beside existing units. Review a representative sample when available. The aim is a considered decision, not an unpleasant surprise after installation.
For a new home, discuss the glass package with the design team before the schedule is released. Shading and orientation are part of that planning. [7]
Should every side of the house use the same glass?
Not necessarily, but mixed packages should be deliberate. Compare the design goals, required performance and appearance. Document the accepted package for each opening so the final order is unambiguous.
Request a Free Glass-Selection Consultation