Window won't stay open? Won't open at all? It's almost always the sash cord.

Double-hung windows in Boston-area homes use a counterweight system hidden inside the frame. Cotton sash cords (or chains) connect the window sash to iron weights through a pulley at the top of the jamb. When a cord breaks — and they all break eventually — the window won't stay up, won't slide smoothly, or won't move at all.

We restore this system to working condition, as part of our full wood window repair service. Most repairs are completed in a single visit.

How sash cord repair works

The repair requires opening the side pocket of the window jamb to access the hidden weights. Here's our process:

• Remove the window stop and lift out the lower sash

• Open the access panel inside the jamb (carefully, to preserve trim)

• Retrieve the broken cord and counterweight

• Install a new cotton sash cord or modern chain (your choice — chains last longer)

• Reattach the weight, set proper tension, and reinstall the sash

• Test smooth operation through full range of motion

What we replace

• Sash cords — traditional cotton cord, the original material

• Sash chains — modern brass or stainless chains, longer lifespan

• Pulleys — replace worn or seized pulleys with new brass or steel hardware

• Weights — replace if missing or recalibrate if window doesn't balance

• Spring balances — for newer double-hung windows that use spring systems instead of weights

Why it matters

A double-hung window that won't stay open is more than annoying — it's a safety hazard. Children and pets can be injured by falling sashes. And a window that doesn't function properly can't ventilate your home or escape during emergencies.

How much does sash cord replacement cost?

We price sash window cord repair per sash, not per hour, and every job gets a written estimate before we start. These are the prices we charge in the Boston area:

• $125 per sash, one rope. When a single cord has broken and the other is still sound.

• $250 per sash, both ropes. Our standard job. The second cord is the same age as the one that failed, so replacing both now avoids a second service call.

• $195 per sash, cord plus pulley. For a lower sash where the pulley is worn or seized and has to come out.

• $290 per sash, conversion to chain. Brass or stainless chain in place of cotton cord, for windows that get used daily.

• $125 to $250 per window, spiral balance. For newer double hung windows that use balances instead of hidden weights.

What changes the price: one cord or two, how the jamb pocket opens, sashes painted shut, and whether you stay with cotton cord or upgrade to chain. Sash cord work takes no deposit. You pay when the window opens, holds, and closes properly.

For comparison, replacing a double hung unit runs $800 to $2,500 per window installed. Cord repair restores the same function for a fraction of that and keeps the original wood, which in a Boston home built before 1940 is usually old growth and denser than anything sold today.

What you are paying for

The rope itself costs almost nothing. The price covers the work around it: taking off the stop and the sash without splitting painted trim, opening the pocket in the jamb, fishing out a cast iron weight that has been sitting inside the wall since the house was built, sizing the new cord so the sash balances and holds at any height, then putting the trim back so the repair does not show.

What makes the price go up

• Sashes painted shut, which have to be cut free before anything else

• No access panel in the jamb, so the pocket has to be opened and closed again

• A pulley that has seized and needs replacing, not just re-roping

• Upper sashes, which sit behind the lower one and take longer to reach

• Storm windows or screens that must come off first

• Windows above the second floor

None of this is guesswork on the invoice. We look at the windows, then put the number in writing before we start.

Doing it yourself

The parts are cheap and the job looks simple on video. What we get called in to fix afterward is usually one of four things: the stop split when it was pried off a painted joint, the weight dropped into the pocket and cannot be reached, the new cord was cut to the wrong length so the sash bottoms out or hangs above the sill, or the sash was forced while it was still painted shut and the rail cracked. At that point the repair costs more than it would have.

What it costs for a whole house

Most people do not do every window at once. A typical call is two to six sashes, the ones that have already failed, which comes to $500 to $1,500 at our standard $250 per sash for both cords. A full first floor is usually four to eight sashes, $1,000 to $2,000. An entire house of twelve double hungs is around $3,000. Grouping windows into one visit costs less than calling us back a second time.

When it is not just the cord

Sometimes the cord is the symptom, not the problem. If the sash rail is soft where the knot sits, the new cord will pull out of it again. If the sill under the window has gone spongy, the sash sits crooked in the opening and wears the rope on one side. We check both during the estimate and tell you before starting, so the number does not change halfway through. Related work: rotten sash repair and window sill repair.

Common questions

How long does it take? A single window is done in one visit. Several windows in the same house are usually finished the same day.

Do both cords need replacing? On a sash that gets used, yes. The second cord is the same age as the one that broke, and coming back for it later means paying for the access work twice.

Cotton cord or chain? Cotton cord is the original material and the right choice for a historic window that is opened occasionally. Chain at $290 per sash lasts far longer and makes sense on windows opened every day.

Do you remove the whole window? No. The sash comes out, the frame and the trim stay in place.

Is it worth repairing a hundred year old window? The wood in a pre-1940 Boston window is old growth, denser and more rot resistant than what a new unit is built from. Re-roping it costs a fraction of the $800 to $2,500 a replacement unit runs installed.

Same-week scheduling

Most sash cord and pulley repairs are scheduled within the same week of your call, across Boston, Newton, Brookline, Wellesley, West Roxbury, and surrounding towns. Call (617) 982-1211 to schedule your free estimate.