Questions to Ask When Replacing Windows
For homeowners working out whether to repair or replace, and then collecting quotes: the questions to ask when selecting replacement windows and the company that will fit them. The 62 questions run in the order the decision goes: repair or replace, the company, choosing the windows, the installation, price and contract, then warranty and what happens after.
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The questions
Each question, and why to ask it
Repair or replace
Which of these windows truly need replacing, and which could be repaired instead?
Why ask it
Fogged glass, a broken balance or a failed lock can often be fixed in the existing frame for far less than a new unit. A company that only sells replacements has little reason to volunteer that, so ask outright and notice whether any window gets a 'leave it alone'.
What is causing the drafts, fogging or rot on the old windows?
Why ask it
A draft may come from worn weatherstripping or an unsealed gap behind the trim and not from the glass at all. Rot at a sill usually means water is getting in above or beside the frame, and a new window set into the same leak will go the same way.
What will new windows change that I will notice, and what will they not fix?
Why ask it
New windows can stop air leaking at the sash, soften street noise and make a stuck window easy to open again. They will not warm a room that is short of insulation, and a promised cut in energy bills is the hardest claim to check, so find out what the figure is based on.
Can the fogged glass be swapped without replacing the whole window?
Why ask it
Mist between the panes means the seal on the insulated glass unit has failed, and on many windows that unit alone can be ordered and fitted into the old sash. Get a price for it before paying for frames you may not need.
If I cannot do the whole house now, which windows would you do first?
Why ask it
The answer shows whether each opening was looked at or the house was priced as a lot. Sensible priorities are windows that let water in, will not open or lock, or sit in the rooms you complain about, and the order should match what you have seen yourself.
Did you check the sills and frames for soft wood, and where did you find any?
Why ask it
An insert relies on the old frame, so a soft sill or a frame that has gone out of square changes the whole recommendation. Have them press an awl into the suspect spots while you watch, outside as well as in.
If I kept the old windows, what would storm windows and new weatherstripping do for them?
Why ask it
On sound old wood sashes, a storm window and fresh weatherstripping take on the drafts and some of the noise at a much lower cost, and they keep glass and trim a historic district may want kept. A company that sells replacements may not raise it, so one call to a window restorer or a carpenter is a fair second opinion.
Are any of the existing windows still under a warranty I could claim on?
Why ask it
Windows put in by a builder or a previous owner may still carry manufacturer cover for seal failure. Look for a name or code etched in a corner of the glass or printed on the spacer between the panes, and have the contractor help identify the maker before anything is torn out.
The company
Are you licensed for window work here, and can your insurer send proof of liability and workers' compensation cover?
Why ask it
Licensing for window installers differs by state and city, so look the number up with the office that issued it. Insurance matters more than usual on this job because part of it happens on ladders at your upper floor, and a certificate sent by the insurer is worth more than a photocopy in a sales folder.
How long has the company traded under this name, and where is its office?
Why ask it
A labor warranty lasts only as long as the company that wrote it, and a long one from a young firm is a promise nobody has tested yet. A street address you can visit and a name that has not changed are small things you can check yourself.
How many jobs a year do you do on houses of this age and wall type?
Why ask it
Setting a window into brick, stucco, old wood siding and vinyl siding are four different jobs at the flashing stage. A crew that mostly fits windows in new construction may be learning on your plaster.
Do your own employees install, or do you use subcontracted crews?
Why ask it
The same window performs well or badly depending on who set it, and subcontracting is common enough that it is not a mark against a company on its face. 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.
Who measures the openings, and does that happen before or after I sign?
Why ask it
Custom units are made to the numbers on the order, and a mistake there means weeks of delay or a gap stuffed with foam. A salesperson's tape is enough for a price, but the order should rest on a second measure by an installer or technician.
Are you an authorized dealer or certified installer for this manufacturer?
Why ask it
Some makers honor their full warranty only when the window is bought through an approved dealer and installed to their written instructions. Look the company up on the manufacturer's own dealer finder instead of relying on a logo on the folder.
If the house predates 1978, are your crews certified for lead-safe work?
Why ask it
In the US, paid work that disturbs paint in a home built before 1978 falls under federal lead-safe rules, and other countries have their own. Ask to see the firm's certificate and how the dust will be contained, since pulling out old sashes and stops is exactly the kind of work that makes it.
Can I speak to two customers whose windows you installed five or more years ago?
Why ask it
A window that looks perfect in its first month can leak in its third winter, so older jobs tell you more than a gallery of fresh ones. Ask those owners whether anything fogged, stuck or let water in, and how long it took for someone to come back.
Choosing the windows
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 cost less, while full-frame takes the old frame out down to the rough opening, which is the only way to see and repair what is behind it. Two quotes that differ wildly on price are often quoting these two different jobs.
Which brand and product line is this, and where does it sit in that maker's range?
Why ask it
Most manufacturers sell several lines under one name, from builder grade up to premium, so the brand alone says little. With the line and series written down you can read the specification yourself and have a second company price the same window.
Which frame material are you quoting, and how does it behave in this climate?
Why ask it
Vinyl, fiberglass, wood and aluminum differ in how much they move with temperature, whether they can be repainted and how they stand up to sun and cold. A dark vinyl frame on a sun-facing wall deserves its own question: have them show you what the maker says about heat for that color.
What are the U-factor and SHGC numbers on the exact units in this quote?
Why ask it
In the US both are printed on the NFRC label on each new window (other countries rate windows on their own labels): U-factor is how readily heat passes through, and SHGC is how much of the sun's heat gets in. They are the fair way to compare one brand with another, and an answer made of marketing terms in place of two numbers means nobody has looked them up.
How many panes are in this glass, what gas is between them and which low-E coating is on it?
Why ask it
Two panes with a gas fill and a low-E coating is the usual starting point, and a third pane adds weight and cost that tend to earn their keep mainly in cold climates. Coatings differ in how much sun they let through, so find out whether one glass package for every wall of the house was a decision or the default line on the order form.
Which style are you proposing for each room: double-hung, casement, slider, awning or fixed?
Why ask it
Style decides how a window opens, seals and gets cleaned. A casement closes tight against its frame and catches a breeze, a double-hung suits a spot over a deck or path where a sash swinging outward would be in the way, and a fixed pane costs least where you never open the window anyway.
How much glass will I lose compared with what I have now?
Why ask it
An insert's frame sits inside the old one, so the visible glass shrinks on every side, and thick frames take more than slim ones. Get the glass size of one window in inches and mark it out with tape on the existing pane.
What would you change on the windows facing the street to cut noise?
Why ask it
Sound reduction comes from laminated glass, panes of different thickness and a tight seal more than from a third pane. If noise is a main reason for the job, ask for the STC or OITC rating of the option quoted and what it adds per window.
Have you replaced windows under an HOA or a historic district before, and who applies for the approval?
Why ask it
Rules on grille patterns, frame color and material come from bodies the contractor does not answer to, so the approval is yours to hold even when they fill in the form. Have it in writing before the order is placed, because custom units usually cannot be returned.
What are my choices for grilles, colors and hardware, and which of them add cost?
Why ask it
Grilles sealed between the panes are easy to clean but look flatter than ones fixed to the surface, and a second color or a wood interior can be a sizeable upcharge. Decide with a sample in your hand at the window itself, in daylight.
What screens come with these windows, and are they full or half?
Why ask it
Screens are easy to forget until the first warm evening. Check whether they are included, what the mesh is made of, and whether a double-hung gets a full screen so the top sash can be opened too.
Can I see and operate a full-size sample of this exact window?
Why ask it
A corner cutaway shows the chambers of the frame and nothing about how the sash slides, tilts or locks. Work a complete unit yourself, feel the weight of the hardware and look closely at the corner joints.
Will the bedroom windows still meet egress requirements at this size?
Why ask it
Replacement can shrink the clear opening enough to fall short of the escape size the local code sets for bedrooms, which matters at inspection and at resale. A contractor who works in your area should know the figure without looking it up.
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.
The installation
Do you pull the permit, and is the fee in this price?
Why ask it
Whether a window swap needs a permit depends on the town and on whether the opening changes size, so ask how it works at your address. 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
Water gets in around a window far more readily than through it. A full-frame answer should mention a sill pan or sloped sill, flashing lapped so water runs outward and a named sealant, and on an insert the thing to hear is what they do about the old frame's flashing, which stays where it is.
Will each window go in to the manufacturer's written instructions, and can I see them?
Why ask it
Makers publish installation instructions for each line, and a warranty claim can be refused when shims, fasteners or flashing depart from them. Asking for the document also tells you whether the crew has read it.
What fills the gap between the new frame and the wall?
Why ask it
That gap is where a well-rated window can still be drafty. Low-expansion foam made for windows and carefully packed insulation are both usual answers, while ordinary high-expansion foam can bow a frame until the sash binds.
What will you do if you open a wall and find rot around the opening?
Why ask it
Nobody can see inside the wall until the old frame is out, which makes this the one surprise to agree on beforehand. The rule to get is that work stops, you are shown the damage and it is photographed before any repair goes on the bill.
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 wrapped over soft wood it hides the rot instead of fixing it. Reused wood trim will need caulking and paint, which may or may not be in the price.
How is the inside left, and does the price include painting or staining?
Why ask it
Drywall returns, casing and paint are often left out of a window price, which hands you a finishing job you did not budget for. Photos of a finished interior from a recent job show the standard the crew stops at.
How many days will the crew be here, and how many openings are open at once?
Why ask it
A careful crew takes out only as many windows as it can close up before it leaves for the day. The number open at one time is what you live with if you work from home, keep pets indoors or are having this done in a cold or wet month.
How will you protect the floors, furniture and plantings near each window?
Why ask it
Old sashes come out with dust, paint chips and sometimes broken glass. Settle who lays drop cloths inside and out, whether moving furniture is your job the night before, and what becomes of the shrubs and flower beds under a ladder.
Who reconnects the alarm contacts and refits the blinds or shutters afterward?
Why ask it
Wired alarm contacts are usually cut out with the old window, and many window crews do not rewire them. Blinds mounted inside the frame may no longer fit a narrower opening, which is a cost to learn about before the order and not after it.
What happens if the weather turns on installation day?
Why ask it
Sealants and foams have temperature limits printed on the tube, and an opening should never sit uncovered in rain. A good answer names the conditions in which they reschedule and how a hole in the wall gets closed if a storm arrives mid-morning.
Do you take away the old windows, and is disposal in the price?
Why ask it
Old sashes, frames and storm windows add up to a trailer load. Haul-away is sometimes a separate line on the quote, so find out before a stack of glass is left beside your driveway.
Price and contract
Can I have the quote itemized by window, with installation shown separately from the product?
Why ask it
A single figure for the house hides which windows are expensive and why. Lines for each opening let you drop or postpone one, and they make it obvious when a second quote left out the big picture window.
Will you leave a written quote with me that I can compare with others?
Why ask it
Some in-home sales visits end with a price on a tablet and nothing to take away, which makes comparing companies impossible. A quote on paper or by email, naming the product line and the scope, is the least a visit to your kitchen table should leave behind.
Which extras most often get added to a job like this after the contract is signed?
Why ask it
Rot repair, wider trim, tempered glass that was missed and interior painting are the usual candidates. Get a unit price for each one now, in writing, so that an extra is a known number and not a negotiation with a hole in your wall.
How long is this price good for, and what would change it?
Why ask it
A quote should stay valid long enough for you to collect others. A discount that ends when the salesperson stands up is a sales technique, and a fair price survives you sleeping on it.
What is the deposit, and what triggers each later payment?
Why ask it
A large deposit puts the risk on you, and payments tied to delivery and completion hand some of it back. Some places cap what a contractor may take up front, so check the rule where you live, and keep the last payment for after a walkthrough.
If I finance through you, who is the lender and what does the loan cost over its full term?
Why ask it
Financing arranged at the kitchen table can come with deferred interest or a fee that is folded into the price. Have the cash price written beside the financed one and compare the terms with your own bank or credit union before agreeing to anything.
Do these windows qualify for a rebate or tax credit where I live, and what paperwork would I need?
Why ask it
Incentives for efficient windows change from year to year and differ by country, state and utility, and they often hinge on a particular rating or certification. Collect the documents the contractor offers, then confirm the rules with the program itself or a tax adviser before counting the money.
What are my rights to cancel after signing, and what happens to the deposit once the windows are ordered?
Why ask it
Cooling-off rules for contracts signed at home differ by country and state, so ask how it works where you live and where the contract says so. Once custom units go into production the deposit is usually spent, which makes the order date as important as the signing date.
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 does the contract say happens if a window arrives damaged or the wrong size?
Why ask it
Custom orders do come in wrong now and then, and a reorder can take as long as the first wait. The contract should say who pays, whether the old window stays in place meanwhile and whether your payment schedule pauses.
Will the contract list the product line, glass package and color for every opening?
Why ask it
The quote is a sales document and the contract is the one that counts. If the U-factor, the grille pattern or the tempered units were agreed out loud, they need to appear on the schedule attached to what you sign, window by window.
Warranty and after
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 the labor cover is often much the shorter of the two.
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. Take down the service number, who pays for the visit and the labor, and what happens if this contractor is no longer in business.
Does the warranty transfer to the next owner, and is there a fee or a deadline?
Why ask it
Many window warranties shrink or end when the house is sold unless the buyer registers within a set period. If you might sell within ten years, the transfer terms are part of what you are paying for.
Does the warranty have to be registered, and who does that?
Why ask it
Some manufacturers want registration within a set number of days of installation, and an unregistered warranty can drop to shorter terms. Get the confirmation along with the order number for each window and keep them with the house papers.
What does the warranty exclude: glass breakage, room-side condensation, screens, labor after the first year?
Why ask it
The exclusions page is where a lifetime warranty becomes specific. Moisture on the room side of the glass, for example, is normally treated as a humidity matter in the house and not a defect, and it is better to read that now than to hear it from a service desk.
What happens at the final walkthrough, and what am I signing?
Why ask it
Go to every window with the lead installer: open it, lock it, check the screen and look at the caulk line outside. Photograph the rating stickers on the glass before anyone peels them, since they are your record of what was installed. A completion form often releases the last payment, so sign it once the list of fixes is done and not before.
Will you come back after the first winter to check for leaks and adjust the sashes?
Why ask it
Houses move with the seasons, and a sash that glided in July can drag in January. A contractor who agrees to a follow-up visit expects their work to stand being looked at again.
How should I clean and maintain these windows, and what would void the warranty?
Why ask it
Low-E coatings, vinyl and factory finishes each have cleaners they do not tolerate, and aftermarket window film is a common warranty exclusion. Bring up the weep holes too, the small drainage slots at the bottom of the frame, which have to stay clear.
Working through the quotes
Practical guidance for the conversation itself
Which questions fit where you are
Before anyone visits
Walk the house with a notepad and write down, window by window, what is wrong: fogged, drafty, stuck, rotten at the sill, or only dated. That list is what the Repair or replace questions work from, and it stops a visit turning into one price for every opening in the house. The license, insurance and reference questions under The company can be settled by phone or email before you book a measure.
When you are selecting replacement windows
Choosing the windows is the group to take to a showroom, or to work through with a full-size sample standing in your own room. Settle insert or full-frame first, then frame material and glass, then style, grilles and screens. Write each answer down per window, because a south-facing living room and a bathroom rarely want the same unit.
When the quotes arrive
Keep The installation and Price and contract for the moment a written quote is in front of you. These are the questions to ask window replacement companies side by side: put the same ones to each, note the answers in columns, and the cheap quote that left out flashing, trim or disposal shows itself.
Before the final payment
Most of Warranty and after can be asked before you sign, and the exclusions are easier to read then than after a leak. Come back to the walkthrough, registration and transfer questions on the last day, while the crew is still on site and the final payment is still in your hand.
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.
- 2On a full-frame job, check that the sill is sloped or a sill pan is fitted, and that the housewrap above the opening laps over the head flashing, not behind 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. Ask for the date the quote is good until, written on the quote, and treat a refusal as the answer.
Ignoring water management
The window is built in a factory, but the joint between it and your wall is made on a ladder in an afternoon. 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.