What should I ask before hiring a window company?
The most important question before signing anything from a window company: Is this a 'today only' price, and can I have 48 hours to get a second quote? National window brands inflate their list price by 200–300%, then 'discount' to a number that's still 2–3x the local installer rate for the same product. The 'today only' pressure exists to prevent you from finding that out.
The second critical question: <strong>Did you inspect the frame and sill for rot before writing this quote?</strong> A window quote that doesn't account for rotted frames is not a real quote — frame rot is common on older homes and can add $200–$800 per window to the job. Discovering it after demo starts is the most common source of window project cost overruns.
The questions that separate pros from problems
Is this a 'today only' price, or can I take 48 hours to get a competing quote?
Local vinyl double-hung installed: $450–$1,200; same from national brands: $900–$2,500+Good answer sounds likeHigh-pressure 'today only' or 'this visit only' pricing is the defining characteristic of national window brands like Window World and some regional chains. The discount is baked into the inflated list price — they always have room to offer it because the list price was never real.
Walk away if…Tell them you need 48 hours. Any company that pulls the 'deal' for taking time to make a major financial decision is telling you what you need to know. Get at least two quotes — one national brand and one local installer — for the same product category.
Did you inspect the frame and sill for rot before writing this quote?
Frame rot repair: $200–$800/windowGood answer sounds likeA quote written without physically inspecting the frame condition is a minimum-case quote. Frame rot is common in older homes, especially around leaking windows. Discovering it after demo adds $200–$800 per window and can halt the job.
Walk away if…Ask: 'Did you check the frame for rot, and is frame repair included in this quote or a contingency cost?' A reputable installer notes frame condition on the quote and discloses contingency pricing upfront.
What does the 'lifetime warranty' actually cover — and is it transferable?
Non-transferable warranty: lost value at resaleGood answer sounds likeWindow warranties have two parts: manufacturer warranty on the frame and glass, and labor warranty from the installer. 'Lifetime' usually means the life of the product at the original installation address — but transfer to a new owner may be limited or require a fee.
Walk away if…Ask for the warranty document before signing. Read what's covered (seal failure, glass breakage, hardware), what's excluded (installation-related air infiltration, screen damage, cosmetic scratches), and whether it transfers to the next homeowner.
Are these insert replacements or full-frame replacements — and which is right for my situation?
Insert: $450–$900; full-frame: $700–$1,400 per windowGood answer sounds likeInsert replacements (new sash into existing frame) are faster and cheaper but only work if the existing frame is structurally sound and properly square. Full-frame replacements address frame rot, settling, and out-of-plumb situations — but cost more. A company quoting inserts on a rotted frame is setting up a future failure.
Walk away if…Ask which replacement method they're quoting and why. If they're quoting inserts, confirm they've verified the existing frames are square and rot-free.
What glass package is included — single-pane, double-pane, or triple-pane?
Triple-pane upgrade: $100–$300/window — mainly for cold climatesGood answer sounds likeDouble-pane with low-E coating is the baseline for most climates. Triple-pane adds meaningful value in cold climates (Minnesota, Wisconsin, upstate NY). Some budget quotes include single-pane or minimal-coating glass — specifying the glass package prevents a bait-and-switch.
Walk away if…Ask for the U-factor and SHGC (Solar Heat Gain Coefficient) of the glass package being quoted. A U-factor of 0.25–0.30 is the target for most climates. If they can't tell you, that's a problem.
What are the payment terms, and who installs — the company or a subcontractor?
Installation accountability gapGood answer sounds likeSome national window brands sell the job and subcontract installation to local crews. If the install is subcontracted, the person whose work you're relying on for decades is not the company you signed with — warranty claims become complicated.
Walk away if…Ask: 'Who actually does the installation — your employees or subcontractors?' And ask about payment terms: no more than 50% upfront, balance on satisfactory completion.
Before you even call
- Count your windows and note their types (double-hung, casement, sliding, bay) before calling — this gives you an accurate basis for comparing quotes and estimating project size.
- Check each window for fogging or haze between the panes (failed seal), rot at the sill or frame bottom, and whether the window locks and lifts properly. Document what you find — this list becomes the scope.
- Look up the window brand in any quote on the NFRC (National Fenestration Rating Council) directory at nfrc.org — this is where legitimate window products list their certified U-factor and SHGC ratings. If the brand isn't listed, their energy performance claims can't be verified.
- For any bedroom window that doesn't open wide enough to escape through, look up your state's egress requirements before getting quotes — replacing a non-egress bedroom window may be a code-required upgrade, not optional.
Unlock the hiring checklist
Use this before you call a window, so you know what to ask and what to avoid.
Red flags that end the conversation
- Any salesperson who tells you the price is only valid 'today' or 'this visit' — take 48 hours and get a competing quote. The deal will still exist, or it wasn't a real deal.
- They write a quote without physically inspecting the frame condition on each window — an untouched-frame quote is a low estimate waiting to grow.
- The 'lifetime warranty' document, when you read it, doesn't cover the scenarios you'd actually file a claim for (seal failure, air infiltration at the frame, installation defects).
- They're quoting insert replacements on windows with visible sill rot, frames that are soft to the touch, or openings that aren't square.
About pricing
Window quotes should itemize: window type and count, glass package (U-factor and SHGC), installation method (insert vs. full-frame), frame condition assessment, contingency cost for rot, trim and capping scope, and warranty terms for both product and labor. If you're replacing 4 or more windows, ask about whole-home pricing — per-unit price drops 15–25% at scale with most installers. For glass-only seal failures on otherwise sound frames, an IGU (insulated glass unit) swap at $150–$400/unit is often the right call — not a full window replacement.
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Related questions
Do window installers need to be licensed?
Licensing requirements vary by state. Most states require a general contractor or home improvement contractor license for window replacement. Always verify on your state contractor board. More importantly, confirm the company carries general liability insurance (minimum $500K) and workers' compensation — window installation involves power tools, heights, and structural opening work.
How much of a deposit should a window company require?
Custom window orders are manufactured to size and non-returnable, so 25–50% upfront is standard. Never pay in full before installation. Final payment should come after you've inspected each window for proper fit, operation, sealing, and trim finish — not before.
What's the difference between insert replacement and full-frame replacement?
Insert replacements remove the old sash and install a new window unit into the existing frame — faster, less disruptive, and less expensive, but the new window is slightly smaller than the opening (the frame itself stays). Full-frame replacements remove everything down to the rough opening and install a completely new frame and sash — necessary when frames are rotted, out-of-plumb, or you want to change window size.
Is triple-pane worth the upgrade cost?
In cold climates (zones 5–7: New England, Midwest, Mountain West), triple-pane windows meaningfully reduce heating bills and eliminate condensation on glass in winter — the payback period is real. In mild or southern climates (zones 1–4), the incremental benefit over quality double-pane low-E is small and the payback period is long. The extra $100–$300 per window is a climate decision, not a general 'better is better' one.