How to Fix a Window That Won't Stay Open: Balance Springs, Tilt Latches, and Support Arms (2026)
A window that falls closed when raised has a failed balance mechanism. This guide covers identifying the window balance type, replacing spiral balances and channel balances in double-hung windows, and fixing casement window support arms.
Window that won't stay open: (1) Double-hung windows use balance springs — the sash weight is counterbalanced by a spiral balance rod or a channel balance with a spring. If the balance fails, the window drops. (2) Find the balance type: look in the side channel of the window — a spiral balance looks like a metal tube with a spiral rod inside. A channel balance is a wider block assembly. (3) Replace the balance: remove the sash by tilting it inward (tilt-latch windows), unhook the old balance, bring it to a window supplier to match the size and weight rating, install the new one. (4) Casement windows: look for a broken support arm (the hinged arm that holds the sash open at an angle) — support arms are sold by the size and brand.
Frequently Asked Questions
How do I tell what type of window balance I have?
Look at the side channel of your window — the vertical track the sash rides in. Spiral balance: a cylindrical metal tube (usually 3/8 or 7/16-inch diameter) with a spiral rod inside it. The rod is tensioned by twisting. Block-and-tackle balance: a flat or rectangular plastic block attached to a ribbon or cord that runs through a pulley system. Channel balance (or coil balance): a wide channel with a spring clip that engages the sash. Older homes (pre-1970): may have original sash weights — cast iron weights hanging in pockets in the wall, connected by a cord over a pulley to the window sash. If your window has no balance hardware visible in the side channel: it likely uses sash weights.
How do I replace a spiral balance on a double-hung window?
Steps: (1) Open the window sash. Find the tilt-latch buttons at the top of the sash — press both latches inward simultaneously and tilt the sash toward you. Lift out the bottom sash. (2) Unhook the spiral balance from the sash shoe (the plastic piece at the bottom of each side channel). The shoe has a hole or slot where the balance rod hooks in. (3) Unhook the top of the balance from the frame — usually a screw holds it. (4) Measure the balance: note the length in inches and the weight stamped on the spiral rod (this matches to the window sash weight). Bring the old balance to a window supply store or order by length and weight. (5) Install in reverse. Tension the spiral rod by twisting it — most balances require 3–5 full turns to set proper tension.
How do I adjust the tension on a spiral balance without replacing it?
If a window drops slowly (not instantly), the spiral balance may just need tension adjustment before full replacement. Tilt the sash in, unhook the balance shoe from the bottom of the sash. Hold the spiral tube firmly and rotate the rod clockwise (for most brands) 2–3 turns to add tension. Re-hook and test. If the window still drops with 4–5 turns added: the spring is fatigued and needs replacement. If the window flies up instead of staying: the balance is over-tensioned, reduce tension by 1–2 turns. Tension adjustment is the first thing to try — it takes 5 minutes and requires no parts.
My casement window will not stay open at any angle. What is broken?
Casement windows stay open via a hinged support arm (also called a casement operator arm or stay arm) that connects the sash to the window frame. When the support arm's friction mechanism wears out or the arm itself breaks, the sash swings freely with no resistance. To inspect: open the window and look for the hinged metal arm — it should hold the sash at a fixed angle. If the arm is cracked or broken at a pivot point: it needs replacement. If it moves freely without resistance: the friction mechanism has worn. Some support arms have an adjustment screw at the pivot — tighten it with a Phillips screwdriver. If the arm is beyond adjustment: measure the arm length and find the manufacturer brand (often stamped on the hardware). Casement support arms are manufacturer-specific.
My window has visible sash weights in the wall pocket. One window won't stay up — how do I fix it?
Original sash weight systems fail when the cord breaks. The cord runs over a pulley at the top of the window frame, through the side channel, and connects to the sash on one end and the cast iron weight in the wall pocket on the other. Fix: (1) Remove the side stop molding (pry off carefully — it's usually nailed). (2) Slide the sash out of the frame. (3) Pull the broken cord stub out of the channel. (4) Access the weight pocket through the small panel in the lower side channel (the pocket access panel). (5) Replace with cotton sash cord (braided cotton, 7/32-inch for most windows) — thread new cord over the pulley, tie to the weight, tie or nail to the sash. (6) Reassemble.
Window that won’t stay open: (1) Double-hung windows use balance springs — the sash weight is counterbalanced by a spiral balance rod or a channel balance with a spring. If the balance fails, the window drops.
Tension adjustment takes 5 minutes and fixes many failing balances without replacing anything.
What you need
- Replacement spiral balance (match length and weight rating to original)
- Flathead and Phillips screwdrivers
- Small pry bar (for stop molding removal if needed)
- Tape measure
Step 1: Identify the balance type
Open the window and look at the side channel. Note whether you see a spiral tube, block-and-tackle assembly, or cord-and-pulley. This determines the repair path.
Step 2: Try tension adjustment first
Tilt the sash inward. Unhook the balance shoe from the sash bottom. Hold the balance tube and rotate the spiral rod clockwise 2–3 turns. Re-hook and test. If tension adjustment fixes the issue: done. If not: replace the balance.
Step 3: Remove the sash
Press both tilt latches simultaneously and tilt the bottom sash inward. Lift the sash out of the channel by raising one end while lowering the other to clear the channel lips.
Step 4: Remove the old balance
Unhook the spiral balance shoe from the sash. Unscrew the balance top from the window frame. Note the balance length and weight rating (stamped on the spiral rod).
Step 5: Install the new balance
Mount the top of the new balance to the frame with the screw. Set proper tension (3–5 turns clockwise on most spiral balances). Hook the shoe onto the sash. Tilt the sash back into the channel and push up until the tilt latches click.
Test: raise the window to different heights — it should hold at each position.
Related guides
- How to Fix a Sticking Window — window that binds in the channel
- How to Replace a Broken Window Pane — glass replacement in double-hung windows
- How to Seal Drafty Windows — weatherstripping after window repairs
- Identify the balance mechanism
Tilt the lower sash inward by pressing both tilt latch buttons simultaneously and pulling the top of the sash toward you. Look at the side jamb: a metal tube with a spiral rod = spiral balance. A flat metal channel with a sliding shoe = block-and-tackle (channel) balance. Older wood windows with no visible hardware = weight-and-cord balance inside the wall. Each type fails differently and requires a different part.
- Test and replace a spiral balance
With the sash tilted in: the spiral rod tip should be hooked into the pivot shoe at the bottom of the sash. If the rod tip is broken or the spring tension is gone (the rod doesn't resist when you pull it down): the balance needs replacement. Note the code stamped on the tube (e.g., 'S270', 'R380') — this specifies the spring tension and length. Order a matching replacement. To install: insert the top of the tube into the jamb channel, hook the rod tip into the pivot shoe, and rotate the rod clockwise 2–3 turns to load spring tension before locking the top clip.
- Replace a block-and-tackle balance shoe
The block-and-tackle system uses a constant-force spring inside a channel to hold the sash. The sash attaches to a plastic shoe via a clip. If the shoe is cracked or the clip has failed: tilt the sash in, unclip the shoe from the sash pivot, and slide the shoe down out of the channel. Measure the channel width (3/4 inch or 1 inch is standard). Order a replacement shoe for your channel size. Slide the new shoe into the channel from below, click the sash pivot into the shoe, and tilt the sash back to vertical.
- Fix a casement support arm
Casement windows (side-hinged, opened with a crank) use a scissor arm or friction hinge to hold the sash open at any position. If the arm no longer holds the sash open: the pivot screws may have loosened (tighten them) or the friction hinge has worn smooth. For scissor arms: tighten the pivot nut at the center of the arm — this increases the friction that holds the arm in position. For friction stays (European-style hinges): the friction pad wears out; replacement friction stays are available by hinge size and weight rating. Replace in pairs (top and bottom).
- Adjust spring tension on spiral balances
If the sash stays open at some positions but falls from others: the spring tension needs adjustment. With the sash tilted in and the rod unhooked from the shoe: rotate the rod clockwise to add tension (counterclockwise to reduce). Add one or two turns and rehook the tip. Test by raising the sash to different heights — it should stay at any position without drifting. If you cannot get adequate tension from adjusting: the spring is fatigued and the balance needs replacement.
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