How should I compare quotes for mid-range replacement windows?

You’re already comparing the right stuff. Equalize the specs first or the cheapest quote is just the one that left things out.

The gap among Simonton, Pella 250, and Andersen 100 is usually insert vs full frame, not the brand. Insert keeps the old frame. Full frame takes it to the rough opening. That’s drafts, condensation, and how long the job lasts.

Have they all quoted the same install method, or is one cheaper because it’s pocketing into the existing frame?

That’s an important distinction. I’d also compare the contractors’ written workmanship warranties even after the window specifications and installation methods are made equivalent. Look for the actual coverage period, whether labor and leak-related service calls are included, who handles manufacturer claims, and any exclusions for existing framing, condensation, or “improper maintenance.”

The service terms matter too: response time, whether repairs are performed by the installing contractor or a third party, and whether labor coverage transfers if the house is sold. A longer window warranty does not help much if installation defects are excluded or the dealer is difficult to reach. I’d have each contractor state those items in the quote, rather than relying on a sales presentation or a manufacturer’s general warranty document.

For the quoted U-factor, SHGC, and air-leakage figures, ask each bidder for the NFRC label or certification reference for the proposed product line, glass package, and operating configuration, plus the size on which the rating is based. U-factor and SHGC can change with dimensions, operating style, grille options, and glass package, so a brochure table or standard test-unit rating may not represent all 12 windows being priced. Air-leakage documentation may be separate from the NFRC label, so ask for that source as well.

Have the proposal identify each unit’s size, configuration, glass package, and applicable performance data. Then compare ratings within the same installation category. A full-frame replacement and an insert can have similar laboratory window ratings but very different installed results if the existing frame, perimeter sealing, or flashing is handled differently. Certified product data is useful, but it is not a substitute for a detailed installation scope.

I wouldn’t assume the insert-versus-full-frame choice is usually the main source of the price gap. It can be significant, but labor access, regional installation rates, interior and exterior trim, finish repairs, disposal, and glass upgrades can easily outweigh the difference between product lines.

I’d ask each contractor to separate the quote into:

- Window units, including the exact glass package and options
- Installation labor
- Full-frame removal or insert preparation
- Interior and exterior trim or finish work
- Flashing, insulation, sealing, permits, and disposal

That makes it easier to see whether a higher price reflects a better scope or simply a more expensive local labor market. A full-frame quote with extensive trim work shouldn’t be compared directly with a basic insert quote, but neither should the entire difference automatically be attributed to the installation method.