Questions covered in this guide
Make a simple exposure map
Label the windows by room and direction, then record when direct sun reaches each one. Note existing trees, overhangs and exterior shades without trying to calculate their effect from memory. Mark rooms where afternoon glare or seasonal discomfort is a concern. The purpose is to give the designer useful observations rather than diagnose the house from a compass direction alone.
Ask why a package was selected
Marvin offers multiple low-emissivity coating options. Its guidance relates coating choice to solar exposure and climate. Ask the bidder to explain the proposed package for each exposure and provide the corresponding product ratings. Have the explanation address your observations. A single specification may be appropriate, but request the reasoning rather than assuming it is automatically the best fit for every opening.
Compare a uniform and varied proposal
Use rows for opening, exposure, current concern, proposed glass package, visible appearance and price. Ask whether using different packages would create a noticeable mismatch across adjacent windows. Have the supplier identify any difference in daylight or solar-heat ratings without converting those ratings into an unsupported bill-saving promise. If a shade or another building improvement is proposed instead, show its scope and price separately. Keep the installer’s recommendations tied to the actual size and product configuration.
Approve a schedule the installer can follow
Attach the final glass schedule to the opening list and order confirmation. Make sure product labels can be reconciled to the intended room before installation. Use supplied prices to compare the complete alternatives in your budget. Our window calculator does not choose a glass coating or model your home’s seasonal energy use; unresolved design questions should remain visible until the responsible professional answers them.
Sources and supported claims
Marvin offers multiple low-emissivity coating options.
Source ↗ · national · Checked 2026-10-12
Its guidance relates coating choice to solar exposure and climate.
Source ↗ · national · Checked 2026-10-12
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