Replacing Window Glass & Parts

A broken or stubborn window is frustrating—and it can compromise both security and energy efficiency.

This guide is your central hub to (1) identify the problem, (2) find the correct replacement part, and (3) follow a clear, step‑by‑step tutorial. Use the visual part finder, the diagnosis table, and the focused mini‑guides below to get from “problem” to “part” to “fix.”

Related help:

• Not opening smoothly? See How to Fix a Stuck uPVC Window.
• Sash dropping? Read How to Fix a PVC Window That Won’t Stay Up.

Visual Part Finder: What Are the Replaceable Parts on a Vinyl Window?

Most vinyl windows have a handful of replaceable parts across two common types: double‑hung and casement.

• Double‑Hung Anatomy (replaceable parts)
  • IGU (Insulated Glass Unit): the sealed double‑pane glass
  • Balances: block‑and‑tackle or spiral systems in the jambs
  • Lock & Keeper: sash lock and frame strike/keeper
  • Tilt Latches: release levers on top of the sash
  • Screen: removable insect screen, usually bottom‑loaded
  • Weatherstripping: seals at meeting rail, jambs, and sill
• Casement Anatomy (replaceable parts)
  • IGU (Insulated Glass Unit)
  • Crank/Operator and Arm
  • Hinges: upper and lower
  • Locking mechanism and Keeper(s)
  • Weatherstripping
  • Screen (interior in many models)

Pro tip for part identification:

• Look for a manufacturer label in the head jamb, sash side, or between panes (tiny etch on glass).
• Balances often have stamp codes (e.g., “28C”); screens use spline diameter (e.g., 0.125 in).
• IGU thickness is commonly 3/4 in or 1 in; a reliable clue is the spacer width visible at the edge.

Quick Diagnosis: Can You Match the Symptom to the Part?

Use this “problem → part → tutorial” table, then jump to the right section.

Guide to Common Vinyl Window Part Replacements

Start with the summary, gauge the difficulty and cost, then click to the deep‑dive tutorial that matches your situation.

Replacing the Glass (Insulated Glass Unit, IGU)

Replace the sealed glass unit when the edge seal fails (fogging) or the glass is cracked/broken. The frame can remain in place if it is structurally sound.

• Difficulty: 4/5 (Pro Recommended)
• Avg. Cost: $MATH_BLOCK_0$$ (IGU + labor)
• Time: 1–2 hours per unit

The Fix (high level):

1. Remove the sash (tilt‑in double‑hung, unclip casement) and place it on a padded surface.
2. Carefully remove glazing beads or stops; score old sealant.
3. Extract the failed IGU; clean the sash channel.
4. Set the new IGU with compatible neutral‑cure silicone; reinstall beads evenly.
5. Reinstall and test for operation; allow cure time.

See How to Replace the Glass in a Vinyl Window.

Identification tips:

• Read the spacer code or measure glass size (daylight + channel depth).
• Confirm thickness: many vinyl sashes accept only specific IGU widths.

Safety:

• Wear cut‑resistant gloves and safety glasses; handle tempered glass edges carefully.

Replacing Window Balances

Balances are spring mechanisms in the jamb that counter the sash weight. When they fail, the sash feels heavy, won’t stay up, or sits crooked.

• Difficulty: 3/5 (Advanced DIY)
• Avg. Cost: $–$$
• Time: 45–60 minutes

The Fix (high level):

1. Remove the sash; find balance type (block‑and‑tackle channel, spiral, or constant force).
2. Note stamp codes and shoe/pivot style; order matching parts.
3. Replace balances and any worn pivot shoes/bars; reattach under proper tension.
4. Reinstall sash and test mid‑travel holding power.

Pro tip:

• Replace balances in pairs so the lift is equal left/right.

Fixing a Stuck or Hard‑to‑Open Window

90% of sticking is dirt + lack of lubrication. Clean tracks and apply a 100% silicone or PTFE dry lube.

• Difficulty: 1/5 (Beginner DIY)
• Avg. Cost: $ (cleaner/lube)
• Time: 20–30 minutes

The Fix (high level):

1. Vacuum tracks and sill; scrub with mild soap; dry completely.
2. Apply a light coat of silicone or PTFE to vertical jambs.
3. Operate sash several times; wipe excess. Avoid oil‑based penetrants.

Replacing a Window Screen

Screens bend or tear easily, but replacement is quick: many pop out from the interior.

• Difficulty: 1/5 (Beginner DIY)
• Avg. Cost: $–$$
• Time: ~5 minutes

The Fix (high level):

1. Locate pull tabs/springs; compress and tilt out.
2. Inspect spline; replace mesh or whole screen if frame is bent.
3. Reinstall by reversing removal.

Simple removal trick: See How to Remove and Replace a UPVC Window Screen

Pro tip:

• Match spline diameter and mesh type (standard fiberglass vs. pet‑resistant).

Replacing Locks, Keepers, and Weatherstripping

Worn or misaligned locks/keepers and weatherstripping cause drafts and security issues. Replacements are inexpensive and quick.

• Difficulty: 1/5 (Beginner DIY)
• Avg. Cost: $
• Time: 15–20 minutes

The Fix (high level):

1. Mark existing lock/keeper positions; photograph for reference.
2. Unscrew and replace with matching parts; adjust for positive engagement.
3. Replace crushed or cracked weatherstripping; press into channel or adhesive‑backed strip.
4. Test closure and seal with a paper test (light drag = a strong seal).

Alignment tip:

• If the lock won’t latch, raise/lower the sash to square it, then adjust the keeper slightly rather than forcing the lock.

Your Essential Toolkit for Window Repair

Most repairs need only basic household tools plus a plastic‑safe sealant/lubricant.

• Power drill/driver and assorted bits
• Screwdrivers (Phillips and flat)
• Plastic putty knife and razor scraper
• Needle‑nose pliers and small adjustable wrench
• Caulk gun with neutral‑cure silicone (for glazing/IGU edge)
• 100% silicone spray or PTFE dry lubricant
• Vacuum with crevice tool, stiff brush, microfiber cloths
• Safety glasses and cut‑resistant gloves

When should you attempt a DIY project instead of calling a professional?

Cleaning/lubing and simple hardware are great DIYs; balances and especially glass are better for experienced DIYers or pros.

• Good for DIY
  • Cleaning and lubrication
  • Screen removal/replacement
  • Lock/keeper swaps and weatherstripping
• Consider a Pro
  • Balance replacement if you’re unsure of type/tensioning
  • IGU/glass replacement to ensure correct sizing and safe handling
  • Casement operator/hinge replacements if sash removal is complex