Window Balance System

{{Infobox
|title = Window Balance Systems
|image        = [[File:Space holder.jpg|215px|alt=Block Glass Windows]]
|header5 = Window Balance Systems
|data6 =  Window Balance Systems for Replacement Windows
|header7 = Description:
|data8 = Homeowners who purchase a double hung or single hung window should be aware of the different types of window balance systems presented for these windows =}}.

A window balance system holds the opening sash of a [[double hung windows|double hung]] or a [[single hung windows|single hung]] window in place when the window is in the open position.

== Window Balance Systems ===
Balance systems are used for double hung and single hung windows. The system enables the window to remain in the open position as with one vertical sliding sash is raised, holding the raised sash in place. 

=== Operation ===
Today's single hung and double hung windows generally use either a block and tackle balance system, a spiral spring balance system or a constant force balance system. All systems enable homeowners to keep their single hung and double hung window sashes raised once they have been opened.  

==== Block and Tackle System ====
The block and tackle window balance system utilizes cords or string that run alongside the jamb tracks on either side of the sash. This system is most often seen in older wood windows and in newer vinyl windows.  The rope is threaded through a small pulley and connects to a counter weight inside the jamb wall. These counter weights help support some of the weight of the window when the unit is in the open position. 


==== Spiral System ====
The spiral window balance system is typically used in vinyl windows. It involves two tubes with spiral rods which are situated on each side of the window where they are attached to the bottom of the window. These tubes are visible when the window is tilted inward, such as when the window tilts in for cleaning purposes. 


==== Constant Force System ====
The constant force balance system is used in all window types including [[wood frame windows|wood]], [[wood clad windows|wood clad]], [[vinyl windows|vinyl]], [[aluminum windows|aluminum]], [[fiberglass windows|fiberglass]] and [[composite windows|composites]]. The system involves a two-piece system that contains a metal coil which is wound under pressure. It is visible when the sash is tilted inward for cleaning. This coil is connected to a plastic shoe which is embedded into the window frame. The constant force system has two major stress points which are subjected to constant forced pressure, holding the opening sash of a single hung or double hung window in a raised position to keep it open. 

=== Comparing Balance Systems for Replacement Windows ===
Researching the different window balance systems is an important part of deciding which single hung or double hung replacement windows to buy. In particular, the repair needs of each window type should be considered to ensure that, if problems occur, the balance system can be fixed easily.

==== Block and Tackle System Repair ====
Lubrication should be attempted first if a block and tackle balance system fails.  If lubrication does not work, the cord may have broken, in which case the entire sash must be removed and new cord threaded through the counterweights in the jamb walls. The rope is then reattached to the window sash and the sash is reinstalled. 

==== Spiral Balance System Repair ====
In a spiral balance system repair, the sash must be removed from the window frame and a spiral balance spring adjustment tool hook can then be hooked onto the bottom of the spring to adjust the spring. This tool hooks onto the spring and pulls it down, allowing the homeowner to spin the spiral rod and tighten the spring to the needed tension. 

==== Constant Force Balance System Repair ====
Constant force balance systems rarely break down, and if they do, lubrication can generally take care of the problem. If lubrication does not solve the problem the system can be repaired by removing the sash and unlocking the shoe which must be slowly guided up the jamb track. The constant force balance system is removed and a new system must is installed, taking care to ensure that the tension is set at the same level as that of the old system. The shoe then lowers back down the jamb track and is locked into place. The window sashes can then be reinstalled.