Questions to Ask When Replacing Windows
Questions to put to a window contractor while you are collecting quotes, covering the type of replacement, the glass and frame specification, how the openings will be sealed, and what the warranty actually covers.
The questions
Open any question for the note
Are you quoting full-frame replacement or inserts, and why that choice for this house?
Why ask it
Inserts fit inside the existing frame and are cheaper but shrink the glass area slightly, while full-frame means removing the old frame down to the rough opening. Two quotes that differ wildly on price are often quoting these two different jobs, so this makes them comparable.
What are the U-factor and SHGC numbers on the exact units in this quote?
Why ask it
These appear on the NFRC label and are the only comparable measure of performance between brands. A contractor who answers with a marketing term rather than two numbers is quoting something they have not looked up.
How many panes, what gas fill and which low-E coating?
Why ask it
Coating choice should differ by orientation, since the glass suited to a south-facing wall is not the one you want on a shaded north side. A single specification for the whole house is a sign of a catalog quote rather than a survey.
Which frame material are you quoting, and how does it behave in this climate?
Why ask it
Vinyl, fiberglass, wood and aluminum differ in expansion, paintability and how they cope with sun and cold. Ask specifically about dark colors on sun-facing walls, where heat distortion complaints usually come from.
Who measures the openings, and does that happen before or after I sign?
Why ask it
Custom units are made to measurements, and mistakes here cause weeks of delay and gaps stuffed with foam. You want to know whether the measurer is the installer or a salesperson working from a tape and a clipboard.
Will the bedroom windows still meet egress requirements at this size?
Why ask it
Replacement can reduce the clear opening enough to fail escape requirements, which matters at inspection and at resale. A contractor who works in your area should answer without hesitation.
Where does code require tempered glass on this job?
Why ask it
Openings near doors, stairs, tubs and low sills usually need it, and it costs more. If tempered glass is missing from the quote where it is required, the price is not comparable to a quote that included it.
Do your own employees install, or do you use subcontracted crews?
Why ask it
Installation quality decides whether good windows perform, and it is the most common source of complaints. If crews are subcontracted, ask who warrants the labor and how long that crew has worked for this company.
Who is the lead on site, and will the same crew be here every day?
Why ask it
Crews that change midway through lose the detail of how the first openings were flashed. Getting a named lead also gives you someone to raise a problem with before it is buried behind trim.
If the house predates 1978, are your crews certified for lead-safe work?
Why ask it
Disturbing painted surfaces in older homes brings specific containment and cleanup requirements. A firm that shrugs at this question is likely to be casual about dust control generally, which you will be living in.
Do you pull the permit, and is the fee in this price?
Why ask it
Unpermitted work can surface during a future sale, and homeowners who pull their own permit become the responsible party at inspection. The answer should say who files, who meets the inspector, and whether the cost is included.
How will you flash and seal each opening, and with what?
Why ask it
Most window failures are water management failures rather than product failures. You want to hear about sill pans or sloped flashing, how the housewrap is lapped, and which sealant is used, because that detail decides whether the wall stays dry.
How is the exterior trim finished: capping, new wood, or the existing trim reused?
Why ask it
Aluminum capping is quick and low maintenance but hides rot rather than fixing it. Reused wood trim will need painting, which may or may not be in the price.
What will you do if you open a wall and find rot around the opening?
Why ask it
This is common in older homes, and the answer reveals how change orders work here. You want a stated hourly or unit rate and a rule about stopping to show you, not a promise to sort it out later.
How is the inside left, and does the price include painting or staining?
Why ask it
Interior drywall returns, casing and paint are frequently excluded, leaving homeowners with a finishing job they did not budget for. Ask to see photos of a finished interior from a recent job.
How many days will the crew be here, and how many openings are open at once?
Why ask it
This determines how much of your house is exposed to weather, dust and noise at any moment. It matters more if you work from home, have pets, or are doing this in a cold or wet season.
How long from deposit to installation, and what usually causes delays?
Why ask it
Custom units are ordered after measurement, so a realistic answer includes manufacturing lead time. Contractors who promise a fast date and then go quiet are usually waiting on the same factory as everyone else.
What is the deposit, and what triggers each later payment?
Why ask it
A large upfront deposit shifts the risk to you, and staged payments tied to delivery and completion are safer. Ask what the final payment is contingent on, ideally a walkthrough where you sign off.
What does the glass warranty cover, what does the labor warranty cover, and for how long?
Why ask it
These are two separate warranties with different lengths. Seal failure and fogging fall under the manufacturer, while leaks and sticking sashes are installation issues, and homeowners often discover the labor cover was one year.
If a seal fogs or a sash sticks in year three, who comes back and how do I reach them?
Why ask it
The practical test of any warranty is whether a person answers. Ask whether the manufacturer's cover transfers to a new owner and what happens if this contractor is no longer in business.
Working through the quotes
Practical guidance for the conversation itself
Making quotes comparable
Fix the scope before you compare prices
Decide with each contractor whether you are pricing inserts or full-frame replacement, and whether interior finishing and exterior capping are in or out. Otherwise you are comparing three different jobs.
Ask for the numbers on the label
Get the U-factor, SHGC and the specific product line in writing for each opening. Brand names alone hide large differences between a builder-grade line and the premium one from the same manufacturer.
Look at installation, not just product
Ask to see two jobs finished more than five years ago, and speak to those owners about leaks and callbacks. Recent photos show tidy work, not durable work.
What to watch during the job
- 1Ask to see the first opening after the old unit is out and before the new one goes in.
- 2Check that the sill is sloped or a sill pan is fitted, and that housewrap laps over the flashing rather than under it.
- 3Confirm shims and fasteners are placed as the manufacturer specifies, since this affects warranty.
- 4Look at how insulation is packed around the frame and whether expanding foam used is the low-pressure type.
- 5Test every sash, lock and screen yourself before final payment.
- 6Walk the outside for gaps in the sealant, and hold back the final payment until the punch list is closed.
Common pitfalls
Buying on payback claims
Energy savings from replacing functional windows are usually modest and slow. Comfort, drafts, noise, operation and rot are better reasons, and they are things you can verify yourself.
Same-day discounts
A price that expires when the salesperson leaves is a pressure tactic, not a market rate. Any legitimate quote will still be honored next week.
Ignoring water management
Most callbacks are leaks, not broken windows. If a contractor cannot describe how they flash an opening, the rest of the quote does not matter.
Assuming the warranty transfers
Some manufacturer warranties are void or reduced on sale, and most labor warranties are short. Read both documents before the deposit, not after the leak.