Double Hung Windows

{{Infobox
|title = Double Hung Windows
|image        = [[File:Space holder.jpg|215px|alt=Block Glass Windows]]
|header5 = Other Names
|data6   = Double Hung Replacement Windows
|header7 = Description:
|data8   = Windows manufactured with two sashes, both of which move vertically.}}

Double hung windows are popular windows which homeowners install in bedrooms, living rooms, dens and family rooms. They are produced with offset lower and upper sashes, each of which moves vertically within the frame. Many people choose to include replacement double hung windows in a home renovation plan because the elongated window fits a large window opening or it is appropriate for the style of a home.   

== Double Hung Windows ===
Double hung windows are a standard replacement option for remodeling home construction projects. Double hung windows consist of two panes, either of which can be lowered or raised to provide an opening of one-half the total surface area of the window panes. The internal mechanism of the double hung windows permit the panes to be easily raised and lowered. Some double hung windows may allow air leakage so homeowners should carefully review the framing options and energy efficiency ratings of a replacement double hung window before making the purchase. 

== Styles  and Placement ==
Double hung replacement windows are an attractive window which can be placed in any area of the house. Double hung windows are appropriate for large window openings and can serve as the center of a bay or bow window or as the flanking windows for bows and bays. Including replacement double hung windows to a home renovation project may include installing non-operable panels along any edge of the double hung window or operable awning, hopper or casement windows either along the double hung window's sides or above or below the window. An atrium double hung window features opening tilt-in top and bottom sashes and is an appropriate window choice for many areas of the home including a closed-in porch or garden room. 

== Considerations ==
Homeowners select replacement double hung windows for a home remodeling project when they want to increase the amount of light and ventilation that is coming into a room, add to a specific architectural style or include a functional window option that offers convenient access for operating and cleaning. 

Double hung windows are not always the right replacement window style for every location. Homeowners, together with their designers, must review a number of considerations before making the decision to install replacement double hung windows in the home.

=== Framing ===
There are a number of different types of framing materials available for replacement double-hung windows. Homeowners may find that some of them, including vinyl and aluminum, are less expensive but provide a lower level of insulation, resulting in higher energy costs. 

More expensive alternatives such as aluminum clad and fiberglass replacement double hung windows may allow the homeowner to recoup the difference in window costs by saving future energy fees. In addition, government rebates are frequently available to help offset the initial costs of the better-insulated windows. 

==== Energy-Efficient Window Framing ====
The U-factor is a standard industry rating that judges the rate at which a window frame conducts heat. A low U-factor indicates that a window frame is energy efficient. Homeowners should review a replacement window's U-factor rating to determine if the frame is well insulated and demonstrates a strong resistance to heat flow. 

===== Wood =====
Wood windows offer a traditional look at a budget cost. An untreated wood window can rot or warp so the homeowner must be prepared to paint or varnish a wood window every year. 

===== Wood with Aluminum Cladding =====
A number of window manufacturers sell wood-frame replacement double hung windows which have exterior aluminum cladding. The aluminum cladding protects the window from the weather's elements while the wood frame provides an elegant wood window which compliments the home's interior. 

===== Aluminum ===== 
Aluminum windows are available in a variety of colors and grades of aluminum. Aluminum is a cold surface and condensation can form on aluminum windows in the wintertime, increasing the moisture level in the house. 

===== Vinyl ===== 
Vinyl windows are another low-cost replacement double hung window alternative. Vinyl windows are available in a range of colors and insulation capabilities. The industry is moving towards better energy performance and some vinyl windows have the seal of the National Green Building Standards for environmental residential construction.  

===== Fiberglass =====
Fiberglass is a relatively new window frame material on the market which provides good insulation and a durable replacement double hung window frame. Fiberglass is available in a range of colors and meets specifications for energy-efficiency. 

==== Composite ==== 
Composite window frames are manufactured from a hybrid of materials. Composite window frames for replacement double hung windows include blends of wood chips and recycled plastic, vinyl with wood veneers and fiberglass with interior wood cladding. 

=== Glazing ===
Glazing alternatives for replacement double-hung windows allow homeowners to select the insulating option that will provide the most energy-efficient window at a cost that meets the remodeling budget while ensuring long-term energy savings. 

==== Energy Efficient Glazing Choices ====
Windows can gain and lose heat through direct conduction through the window's glass or through heat radiation. Replacement double hung windows feature a large glass area which, with properly insulated glazing, will cut down on the transfer of heat and cold, reduce the sun's rays and provide an energy efficient window.    

===== Multi-Pane Glazing =====
Many window manufacturers present alternatives for double or triple-pane glazing to offer better-insulated windows. The manufacturers often pump insulating argon or krypton gas into the gaps between the panes to better insulate the windows. The panes are then sealed into the window's sash to prevent any possibilities of escaping gas. Triple-pane glass is frequently recommended for homes built in extreme climates and costs little more than double-pane glazing. 

===== Low E Coating =====
The Low-E (Low-emissivity) coating is an invisible layer of metallic oxide which is applied to a replacement double hung window to control heat transfer caused by the sun's rays. The Low-E coating can reduce energy loss by as much as 30% - 50%.  

=== Sizes and Shapes ===
Replacement double hung windows are available in sizes ranging from 24 to 48 inches wide by 36 to 72 inches high. They come prefabricated and ready for installation. Double hung windows open vertically with a sash that slides up and down, making them appropriate for square openings as well as for rectangular horizontal or vertical openings.  Replacement double hung windows are suitable for any area of the house, from small bathroom windows to panoramic picture windows. The windows are easy to operate. Many manufacturers produce optional tilt-in double hung windows which make the windows easy to clean. 

=== Accessories ===
Replacement double hung windows come with hardware and other accessories including locks, push-handles, grilles and screens.

==== Hardware ====
The sash lock on a double hung window locks the sash in place to prevent unwanted intruders. Additionally, a wood frame window may contract in the wintertime and the upper sash can slip. The sash lock will hold the sashes in place. 

A handle is installed at the bottom of the double hung's lower sash to enable the homeowner to push the window open. 

==== Screens ====
The screen is clipped on to the outside of a double-hung window. The clip allows the homeowner to easily remove the screen to clean the window and the screen. 

==== Grilles ====
Grilles of various colors and patterns are available for double hung replacement windows. These grilles can either be purchased separately, as a clip-on accessory, or as custom-installed grilles which are placed into the glass of a multi-pane window while the window is being manufactured in the factory. 

== Installation ==
Window installers can keep a couple of installation hints in mind when preparing to install a double hung replacement window. The installer should ensure that the opening for a replacement double-hung is large enough to accommodate the window plus a false frame, with an additional 3/4" on all sides. In addition, double hung windows have a reputation for leakage so the installer should seal the perimeter of the window opening with sticky sheets of self-adhering waterproof membrane and strips of metal flashing before sealing it with caulking.