A window won't stay open: causes and fixes
When a double-hung window won't stay open and drops the moment you let go, the cause is almost always a broken or worn sash balance, the spring mechanism hidden in each side jamb that counterweights the sash. It is rarely the whole window. On most units the balance is a replaceable part for under $40, so diagnose the balance type first, then decide repair versus replace.
For 2.5 years I coordinated installs and service calls at Renewal by Andersen, which meant a lot of time with the hardware inside the jamb. A window that drops when you raise it is the single most common operating complaint I saw, and it almost never means a new window. It means the spring balance behind the jamb liner has given up on one or both sides. The fix depends entirely on which kind of balance your window uses, so the whole job is really one question answered three different ways. Let me walk you through it the way I would at your own window.
Why your window won't stay open
A double-hung sash is heavy, and it does not float on its own. Each side jamb hides a spring balance whose only job is to offset the sash weight so it stays put wherever you leave it. When a window won't stay open, that balance has failed: a spring lost tension, a cord snapped, a coil broke, or the little plastic pivot shoe that connects the sash to the balance cracked. With nothing counterweighting it, gravity wins and the sash slides down.
A few tells point straight at the balance. If the sash drops fast and hard, a balance has snapped or detached completely on at least one side. If it drifts down slowly, the springs are tired but not gone. If one corner sags lower than the other when you raise it, one side has failed and the other is still holding. You may also hear a spring rattle inside the jamb or see a frayed cord or a shoe stuck at the bottom of the track. None of that means the window itself is bad. It means a serviceable part inside it is.
The three balance types, and how to tell which you have
There are three balance systems in double-hung windows, and identifying yours is the whole game because the repair differs for each. Pull the sash out (most tilt in) or peek behind the jamb liner and you can usually spot which one you have in under a minute.
Here is how the three compare, since the part you order and whether it is a DIY job both hinge on this:
| Balance type | Common in | How it works | How it fails |
|---|---|---|---|
| Block-and-tackle | Vinyl and aluminum double-hung | Pulleys and a cord stretch a spring sized to the sash weight | Cord frays or snaps; spring loses tension |
| Spiral | Older and some aluminum-clad wood units | A twisted rod inside a tube provides adjustable tension | Spring weakens with use; rod loses grip |
| Constant-force (coil) | Newer vinyl, especially tilt units | A rolled stainless steel coil, like a tape measure, holds even tension | Coil cracks or pops out of its housing |
A few quick identifiers. Block-and-tackle balances ride in a metal or plastic channel and you can usually see the cord and pulleys. Spiral balances are a long tube with a twisted rod visible inside, and they often have a small tilt-adjuster at the bottom you turn to add tension. Constant-force coil balances look like a flat curled spring tucked in a pocket behind the jamb liner, with no cord at all. If you are still unsure, snap a photo of the jamb and ask Zig to help you identify it before you buy a part.
Is fixing a window that won't stay open a DIY job?
For most homeowners, yes, with one honest caveat. Replacing a block-and-tackle or constant-force balance is a genuine DIY job with basic tools and a $20 to $40 part, and re-tensioning a spiral balance is even simpler. The caveat: balances are sized and rated to your exact sash weight, so the risk is not the labor, it is ordering the wrong part.
The general sequence is the same across types. Tilt or remove the sash, release the old balance from its take-out clip or screws, match the replacement to the original (length, channel width, and the spring-strength number stamped on the metal), then reinstall. A spiral balance often just needs re-tensioning: you disengage the tilt pin, turn the rod a few clockwise turns to add tension, and re-engage. That can fix a slow-dropping sash with no new parts at all.
Where I would tell a friend to stop and call someone: if the sash itself is racked or the jamb liner is cracked, if you cannot find a matching balance for an obsolete window line, or if the window is a large or upper-floor unit that is awkward to handle safely. A balance is cheap. A dropped sash on a second-story stairwell window is not worth the gamble.
When a window won't stay open but the fix is replacement
Replacement is the honest call in a narrow set of cases: the balance part is discontinued and no match exists, the sash or frame is rotted or warped so a new balance has nothing sound to seat against, or the window is single-pane and aging and you were going to replace it anyway. Outside those, a balance swap is almost always the right, cheaper answer.
Two situations push toward replacement specifically. First, obsolete hardware. Window lines get discontinued, and once the manufacturer stops making a balance and the aftermarket runs out, you cannot reliably keep a 25-year-old unit operating. Second, a compromised frame. If water got in and the wood around the jamb is soft, a new balance will not hold because the screws have nothing solid to bite into. That is a frame problem wearing a balance problem's costume, and our rotted frame guide covers where that line sits. The whole-house version matters too: one window that won't stay open is a repair, but eight aging windows all dropping is usually a sign the housing stock has reached the end of its service life, and at that point new units make more sense than a balance kit per opening.
If you do land on replacement, casement windows are worth knowing about, because they sidestep this failure mode entirely: a casement window cranks open and locks at any position with no spring balance to wear out, which is one reason I steer some homeowners toward them for hard-to-reach openings. For a same-style swap, see double-hung windows and the broader window options.
What a balance repair versus replacement costs
Price the small fix before you price the big one, because the gap is large. A balance kit and a DIY afternoon runs roughly $20 to $40 in parts per window; a professional balance service call is more, but still a fraction of a new unit. A full replacement window installed in this market typically runs [data pending: installed price range for a single double-hung replacement window in DC/MD/VA, from OneStep catalog pricing], driven by size, material, and whether the frame needs full-frame work or a simpler insert.
Replace the balance
A balance kit and a DIY afternoon. A professional balance service call is more, but still a fraction of a new unit. This is the right, cheaper answer outside the narrow replacement cases.
Replace the window
The balance is discontinued with no match, the frame is rotted so a new balance has nothing sound to seat against, or the whole house is dropping sashes. A full replacement window installed runs more, driven by size, material, and whether the frame needs full-frame work or a simpler insert.
One thing to clear up for 2026, because it still trips people up: there is no federal window tax credit right now. The federal Section 25C energy-efficient home improvement credit, which used to return up to $600 on qualifying windows, expired for installs placed in service after December 31, 2025, per the IRS. Any contractor pitching a federal window tax credit on a 2026 job is quoting an expired program. Utility or state efficiency rebates may still apply depending on your provider and jurisdiction across DC, Maryland, and Virginia: [data pending: current DC/MD/VA utility and state window/efficiency rebate programs and amounts (e.g. Pepco, BGE, Dominion, Washington Gas)]. Confirm any rebate against the program's own page before counting on it. For the wider picture, see the single-window replacement cost breakdown and the master window replacement cost guide.
How OneStep helps you avoid replacing a window you could have fixed
A dropping sash is a $30 part on most windows, and our process is built to get you to that answer first rather than to a quote. Send Zig a photo of your jamb, let it identify the balance type, and talk through whether a kit solves it, because fixing the part is the result we want here, not selling you a window you do not need.
When the balance really is unsalvageable, the process takes the pressure out of what comes next. You preview and price your real openings in the 3D configurator, measure by AI phone-video instead of waiting on a sales appointment, and get itemized pricing with no rep running a clock at your dining table. To figure out what you are dealing with, ask Zig in the chat; when real numbers on your openings are the next step, price your windows in the configurator. The window problems hub sorts the full range of window symptoms by repair-versus-replace, and a stuck window that will not open at all is a different diagnosis worth reading next.
See it on your own house first
Preview a clean replacement on a photo of your actual window and get itemized pricing before you decide.
Frequently asked questions
Why won't my double-hung window stay open?
Almost always because the sash balance inside one or both side jambs has failed. The balance is a spring mechanism that counterweights the sash so it stays where you leave it. When a spring loses tension, a cord snaps, or a coil breaks, gravity pulls the sash back down.
Can I fix a window that won't stay open myself?
Usually yes. Replacing a block-and-tackle or constant-force coil balance is a DIY job with basic tools and a part that typically costs $20 to $40, and a spiral balance often just needs re-tensioning. The main risk is ordering the wrong balance, since they are rated to your specific sash weight.
How do I know which window balance I have?
Tilt the sash in or look behind the jamb liner. A visible cord and pulleys means block-and-tackle, a long tube with a twisted rod inside means spiral, and a flat curled spring with no cord means a constant-force coil balance. The part you order depends on which one it is.
Should I replace both window balances if only one is broken?
Yes. Balances are sold in pairs and wear at a similar rate, so replacing both keeps the lift tension even. If you replace only the failed side, the mismatched tension makes the sash hang crooked and can pop it out of the shoe over time.
Is a dropping window a sign I need to replace the whole window?
Rarely. A dropping sash is a balance problem, and the balance is a serviceable part on most windows. Replacement only makes sense when the balance is discontinued with no match available, the frame is rotted so a new balance has nothing sound to seat against, or the window was already at the end of its life.
How much does it cost to fix a window that won't stay open?
A DIY balance kit usually runs $20 to $40 in parts per window plus an afternoon of labor. A professional service call costs more but is still far less than a full replacement window. Pricing the balance repair first almost always saves you money.
Next step
Identify the balance type first, then fix only the part that actually failed; that is where the savings are. A single worn balance on a sound, modern window means you order the matching kit and keep the window. An obsolete balance or a gone frame is the one case worth pricing a replacement on your own openings, on your own terms, before any salesperson sets the terms for you.
Start your measurement in 5 minutes
Snap a photo with your phone, get AI measurements and an honest price — no salesperson, no in-home pitch.
Keep reading: the window problems hub covers every symptom from foggy glass to drafty windows, the complete guide to replacement windows walks the whole decision, and the person behind every page here is Anthony Moorman.