Quick answer
A double-hung window that won't stay up has broken sash balances — the spring-loaded mechanisms inside the window frame that counterbalance the sash weight. Modern vinyl windows have replaceable spring balances ($15–$40); older wood windows have rope-and-weight systems requiring more work. Replacement is DIY-capable but requires removing the sash. Both balances typically fail within a year of each other — replace as a pair.
Key facts
| Common causes | Broken spring balance (vinyl windows); Disconnected clip or shoe; Broken sash cord (wood windows); Bent or damaged track |
|---|---|
| DIY difficulty | Moderate |
| Time to fix | 30 min |
| Parts cost | $15–$40 parts |
| Tools needed | Screwdriver, needle-nose pliers |
| When to call a pro | Older wood windows with rope-and-weight balances |
What's happening
Double-hung windows have a sash (the moving panel) that must be counterbalanced or it would fall shut under gravity. Modern vinyl windows use spring-loaded balances hidden in the frame — a coiled spring in a metal channel connected to the sash by clips or shoes. When the spring loses tension or the clip breaks, the sash won't stay up. Older wood windows use rope-and-weight balances (metal weights hidden in the wall connected to the sash by rope over pulleys) — same failure mode, more complex fix.
Common causes (ranked by frequency)
- Broken spring balance (vinyl windows) 70% of cases
Coiled spring inside the vertical channel of the frame loses tension or breaks. Replacement balance $15–$40 per side. Both sides usually fail within a year — replace as pair.
- Disconnected clip or shoe 20%
The connection between the balance and the sash comes loose. Often reattachable without new parts.
- Broken sash cord (wood windows) 8%
Old wood windows use rope-and-weight balances. Rope breaks over decades. Fix requires opening the frame access panel.
- Bent or damaged track 2%
The channel the sash slides in is dented or bent. Sash catches. Requires removing sash and inspecting/repairing track.
How to diagnose
- Identify window type. Modern vinyl (post-1990s), older wood (pre-1980), or aluminum (1970s-80s). Different balance types.
- Lift the sash halfway and release. Falls fast = both balances broken. Slow fall = one balance broken.
- Check the sides of the frame — vinyl windows have a channel visible when the sash is up. Look for the balance mechanism.
- Note the manufacturer (usually stamped on the frame or in the corner of the glass). Order matching replacement balances.
The fixes
Fix #1 — Replace vinyl window spring balances Modern windows
Match your window brand and balance size. Andersen, Pella, Milgard, and generic vinyl all use similar spring balance designs.
Tools
- Small flathead screwdriver
- Needle-nose pliers
- Utility knife
Materials
- Two replacement spring balances (match your window brand + size)
- Fully lift the sash. Tilt it inward by pressing the two tilt latches at the top corners of the sash.
- Remove the sash — with sash tilted, lift one side out of the pivot bar in the frame.
- Locate the balances in the vertical channels on either side of the frame.
- Unhook the top of the balance using a small screwdriver — it usually clips or slides out.
- Pull out the balance from the top.
- Insert the new balance in the same position — align the pivot bar/shoe with the position that matches the sash pivot.
- Reinstall the sash by reversing the removal — insert one side into pivot, then the other.
- Test.
Prevention
Lubricate window tracks annually with silicone spray (never oil — attracts dust). Don't force windows that stick — the sash weight can damage balances. If a balance breaks on one side, the other typically fails within 6–12 months — consider replacing as a preventive pair.
When to call a pro
When to stop and call a pro
- Older wood windows with rope-and-weight balances — access can require significant disassembly.
- Window frame itself is warped or damaged — requires professional evaluation.
- Multiple windows in the home with balance issues — could be a manufacturing defect worth pursuing warranty.
- You're not comfortable with sash removal — glass breaks easily.
Window repair service call: $100–$200. Balance replacement per window: $100–$180. Full sash replacement: $200–$500. Window replacement: $300–$1,200 per opening.
Cost estimate
Cost estimate
Frequently asked questions
Check the corner of the glass for an etched logo, look for a stamp or sticker on the frame, or check the maintenance manual (if you have it). If you're stumped, take detailed photos and measurements to a window supply store — they can often identify.
Yes — for a few days while you order parts. Never as a long-term solution — a stick can slip, and the falling sash can break glass or injure someone.
No — balances vary by brand, window size, and sash weight. Match your existing balance's length and the number stamped on it. Generic balances work for many vinyl windows but not all.
15–25 years typically. Cheap builder-grade windows fail earlier (10–15 years); premium windows last longer. Simultaneous multi-window failure often indicates the whole window run was low-quality — consider replacing rather than repeatedly repairing.