Replacing a channel balance or “block & tackle” balance on a single-hung window

Our new Energy Quest vinyl windows use a constant force steel coil balance that never needs replacement.  But what if you’ve already replaced your windows a few years ago? Sometimes they just need a little TLC to get them working like new again. In a single-hung window (where the bottom half slides up), the most common issue is a bad balance. Over years of use it could be broken or damaged. Replacing a balance yourself is easy and much cheaper than calling for a repair service.

  • Locate the balance clips in the side of frame. There may be vinyl or metal ‘stops’ covering them.Closed balance clip
  • Pull the clips out into the open position. This will let you move the lower sash of the window all the way up and out of the frame.Open balance clip


  • Next put the hook end of the balance into one of two holes in the side of the frame.
    Hook end of channel balancebalance 4


  • By pulling the balance down you put tension on the spring, and the plastic head can fit under the open metal clip.Tension balancePlastic head under clip
  • Put the lower sash back into the frame by placing it in the track ABOVE the balance clips. You will feel it sit on top of the balance heads. Slide the window closed.sash in frame


  • Be sure to push the clips closed (flush to the frame) and replace any vinyl or aluminum stops.closed balance clip


Window balances come in a lot of different sizes. You can tell what size of balance you need by the size of your window. The height of your glass is usually the length of the metal channel of the balance itself, not including the plastic head and end caps. The balances will have a stamp that includes two, 2 digit numbers, for example it might say “28 30”. The first set will be the height of the glass (28”), and the second set is a weight code (up to 30 lbs). The best way to determine what size of balance you need if you do not already have an old part, is to call up the manufacturer, give them the overall size of the complete window, and they can tell you what size you need. We recommend replacing both balances at once so they have equal tension, and allows the window to travel evenly. If you replace just one side, the window may feel lopsided and hard to slide.

If you are still having problems, please feel free to visit our shop and showroom and we can walk you through the process. Or please give us a call and we’ll help you out!