"What is the U-factor of the windows you are quoting, and is that right for my climate?"

Why it matters: U-factor measures heat transfer through the window (lower is better). In cold climates, a U-factor below 0.

"What is the SHGC, and is it appropriate for my climate?"

Why it matters: Solar Heat Gain Coefficient measures how much solar heat comes through the glass (lower = less heat gain). In hot climates (South, Southwest), a low SHGC (below 0.

"What is the frame material, and what are the tradeoffs?"

Why it matters: Vinyl frames are the most common: low maintenance, decent insulation, affordable. Fiberglass is stronger, more dimensionally stable, and better for large windows.

"Are you doing a full-frame replacement or a pocket (insert) installation?"

Why it matters: A pocket install removes the old sash and installs the new window into the existing frame. It is faster and cheaper but leaves the old frame in place, which may be rotted, air-leaking, or improperly sized.

"How do you flash and seal the window after installation?"

Why it matters: Window flashing is the system that prevents water from getting between the window frame and the wall. It requires self-adhesive flashing tape at the rough opening, head flashing above the window, and sill pan flashing below.

"What is your air sealing process around the window frame?"

Why it matters: A window can have a great U-factor and still perform poorly if air leaks around the frame. The gap between the window frame and rough opening should be filled with low-expansion spray foam or insulation, not just caulk.

"What brand and exact model are you quoting?"

Why it matters: Without a specific model, you cannot verify the performance specs, look up independent reviews, or hold the installer to the product they quoted..

"What does the manufacturer warranty cover, and what is your installation warranty?"

Why it matters: Window warranties typically cover glass seal failure (foggy glass between panes), hardware, and frame defects. The installation warranty covers air and water infiltration due to improper installation.

"Is a permit required for this replacement?"

Why it matters: Window replacement permits are required in many jurisdictions, especially for structural changes or if the window size is changing. A permit means a building inspection, which catches installation problems.

"Are disposal of old windows and interior trim work included?"

Why it matters: Removing old windows and hauling them away is labor and disposal cost. Interior casing repair or replacement after a full-frame install is also often extra.

"How do you handle windows that have rotted framing in the rough opening?"

Why it matters: You do not know the condition of the rough opening until the old window is out. A good installer has a protocol for this: check, document, repair at an agreed price per linear foot, or call you before proceeding.

"What is the payment schedule?"

Why it matters: For window jobs, a deposit at signing, second payment when windows arrive (they are custom-ordered and non-returnable), and balance on completion is standard..