Expand Your Knowledge of Windows

Are High Quality Windows Worth the Cost?
Is your Money Flying out the Window?
What are Low E Coatings?
All Low E Windows are Not Created Equal
Window Styles
A Closer Look at a Simonton Vinyl Replacement Window
Glossary of Terms

Are High Quality Windows Worth the Cost?

Anyone who has lived with low quality -- or poorly installed -- windows can attest to the problems they can cause. Walls and floors suffer damage from dampness. Fabrics fade. Energy costs skyrocket. A home built with mediocre windows to shave upfront costs can turn into a big ticket headache for buyers and builders in the long run. On the other hand, the finest quality windows, correctly installed by trained professionals, pay for themselves over and over by saving money on energy bills, sparing damage to interiors and maintaining ease of operation throughout their lifetime. Studies have shown that over 40% of a typical home's annual energy budget is consumed by windows and doors. High quality windows and doors with Low E coatings and insulating gasses are twice as efficient as those manufactured just ten years ago, and they are 40% more efficient than products manufactured using common building code guidelines.

Many buyers don't realize this until after they've moved in. When they're making the decisions that will affect the quality of their home, buyers rarely focus on windows. And the few who do usually don't know how to weigh the added quality against the added cost. According to Big Builder Magazine, the finest quality windows and installation can cost up to 15 percent more than the low-quality counterparts, but are worth every bit of the added cost (Publication 2003-09-24). Back to top

This is an infrared photograph. The closer to red an area is, the more heat radiating out from it.

Is your Money Flying out the Window?

Windows bring light, warmth, and beauty into buildings and give a feeling of openness and space to living areas. They can also be major sources of heat loss in the winter and heat gain in the summer. In 1990 alone, the energy used to offset unwanted heat losses and gains through windows in residential and commercial buildings cost the United States $20 billion (one-fourth of all the energy used for space heating and cooling). However, when properly selected and installed, windows can help minimize a home's heating, cooling, and lighting costs.

Double- or triple-pane windows have insulating air- or gas-filled spaces between each pane. Each layer of glass and the air spaces resist heat flow. The width of the air spaces between the panes is important, because air spaces that are too narrow (less than 1/2 inch or 1.3 centimeters) have lower R-values (i.e., they allow too much heat transfer). Advanced, multi-pane windows are now manufactured with inert gases (argon or krypton) in the spaces between the panes because these gases transfer less heat than air.

Energy efficient windows save a lot of money. By minimizing air leakage and improving thermal performance of your windows, you could reduce heat loss through windows by up to 50 percent and reduce your energy bills.

Energy efficient windows increase the comfort level in your home by reducing cold drafts and making a house feel warmer in the winter and cooler in the summer. They help control condensation because the interior surfaces of energy-efficient windows stay warmer, allowing you to maintain a higher level of humidity without worrying about condensation on your windows.

They also last longer because condensation can cause premature deterioration of windows, walls and finishes leading to high maintenance and replacement costs. Back to top

What are Low E Coatings?

Low-emittance (Low-E) coatings are microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a glazing surface primarily to reduce the U-factor by suppressing radiative heat flow. The principal mechanism of heat transfer in multilayer glazing is thermal radiation from a warm pane of glass to a cooler pane.

Coating a glass surface with a low-emittance material and facing that coating into the gap between the glass layers blocks a significant amount of this radiant heat transfer, thus lowering the total heat flow through the window. Low-E coatings are transparent to visible light. Different types of Low-E coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain. Back to top

All Low E Windows are Not Created Equal

Courtesy: U.S. Department of Energy, A Consumer Guide to Energy Efficiency and Renewable Energy

Most window manufacturers use R-values (Higher is better) and U-values (Lower is better) in rating their windows. The R-value is the measure of a material's resistance to the passage of heat. The higher the R value, the more insulating "power" a material has. With vinyl windows installed, your home needs less energy to keep your home heated in winter or cooled in the summer, lowering your energy bills. Standard single-pane glass has very little insulating value (approximately R-0.9). It provides only a thin barrier to the outside and can account for considerable heat loss and gain. Traditionally, the approach to improve a window's energy efficiency has been to increase the number of glass panes in the unit, because multiple layers of glass increase the window's ability to resist heat flow.

When comparing different windows, you should ensure that all U- or R-values listed by manufacturers: (1) are based on current standards set by the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE), (2) are calculated for the entire window, including the frame, and (3) represent the same size and style of window.

The following five factors affect the R-value of a window.

The type of glazing material (e.g., glass, plastic, treated glass)
The number of layers of glass
The size of the air space between the layers of glass
The thermal resistance or conductance of the frame and spacer materials
The "tightness" of the installation (i.e., air leaks, insulation, proper caulking, etc.).

Window Styles

Name	Description	Typical Applications
Awning	Windows that are hinged at the top that swing out for ventilation.	Bathrooms, Combine w/Large windows
Single/Double Hung	A window with two sashes where one or both sashes slide vertically.	Bedrooms, Family Rooms, Kitchens, Dens
Horizontal Slider or Rolling window	A window with two sashes where one or both sashes slide horizontally.	Bedrooms, Family Rooms, Kitchens, Dens, Combinations
Casement	A window or windows hinged on one side that open as far as 90 degrees to the building using a crank.	Bathrooms, Bedrooms, Living Rooms, Combine w/Large windows
Direct-Set Geometrics	These are fixed windows. Since they have no moving parts, they can be tailored to meet just about any desired geometric shape.	Entry Ways, Living Rooms, Combine w/Large windows
Circle Top	As the name describes, these windows typically have a flat bottom and a circular or arched top. These are typically used in combination with another window or door.	Entry Ways, Living Rooms, Combine with doors or large windows

Examples of Combinations

Outline	Name	Description
	Angled Bay	A single large, fixed center window with 2 windows at 30, 45, or 90 degrees to the building. Side windows are typically vertical sliders or casement.
	Bow	Four or more windows configured to form a radius. Typically made of either vertical sliders or casement windows.
	Picture Combination	A single large, fixed center window with 2 adjacent side windows. Side windows may be either horizontal or vertical sliders or casement.
	2-Wide	Two vertical slider windows installed side-by-side. This is a basic building block for a "wall of windows".
	3-Wide with transoms	Three vertical slider windows installed side-by-side with awnings or fixed transoms across the tops.
	2-Wide with transom	Two casement windows installed side-by-side with an awning or fixed transom across the tops.
	Cathedral	Two casement windows with a half cloverleaf top circle
	Three wide with awnings	Three fixed windows with awnings on the bottom.

A Closer Look at a Simonton Vinyl Replacement Window

Fusion-welded Frame and Sash
Vinyl profiles are heated to over 500 degrees then fused into a one-piece unit.
Denny Clip™ Pivot System
Disc-shaped clip keeps sash in perfect alignment for smooth operation.
Air Lok™
Flush-mounted for a smooth interior finish, Air Loks™ allow for partial ventilation.
Simonton Sill®
The unique triple-stepped sill is sloped to promote faster water runoff than conventional sills.
Secure Nest™ Cam Lock
Low-profile cam wraps inside the keeper for an extra tight seal.
Secure Seal™ Meeting Rail
Meeting rail features interwoven wool pile weatherstripping with mylar fin to protect against air infiltration.
Stainless Steel Constant Force 3/4" Coil Spring Balance System
Springs will never need adjustment and provide constant tension to hold the window in any open position.
Tilt Latch
Convenient latches on top allow sash to tilt in for easy cleaning.
Lift Rail
Contoured and molded into the sash, lift rails will not loosen or break off over time.
Step Jamb
Interior side jambs are stepped to roadblock direct airflow paths.
3/4" Glass Penetration
I.G. units are placed 3/4" into the sash, 1/4" more than other manufacturers, to provide better insulation.
Sensor Glass™
Unique low emissivity Sensor Glass™ works like an invisible shield to maintain even temperature control and block harmful UV rays.
Solid Silicone Foam Spacer
Foam spacer is almost 1000 times less conductive than traditional aluminum spacers.
Multiple-chambered Profiles
Vinyl frames are filled with many high-insulating dead-air chambers.
Weather Guard Contact Points
24 weathering lines surround the unit to make it virtually airtight.

Glossary of Terms

Air Chambers: Small honeycomb spaces within the sash and frame which help to insulate and strengthen the window.
Air Infiltration: The amount of air that passes between a window sash and frame. In windows it is measured in terms of cubic feet or air per minute, per square foot of area. The lower the number, the less air the window lets pass through.
Air Latch: Latch mechanism on the interior face of the sash that retains the window in a partially open position for ventilation.
Air Lok™: Latch mechanism on the interior face of the sash which retains the window in a partially open position for ventilation.
Angled Exterior: A sloped extension from the frame that adds an aesthetically-pleasing dimension to the exterior of the window.
Argon Gas: An odorless, colorless, tasteless, non-toxic gas which is six times more dense than air. It is used to replace air between the glass panes to reduce temperature transfer.
Awning Window: A top-hinged window that swings outward for ventilation.
Balance covers: Covers the balance cavity holding the coil-spring balance system inside the jamb.
Balance System: Device for holding vertically sliding sash in any desired position through the use of a spring or weight to counterbalance the weight of the sash.
Bay Window: An angled combination of three windows that project out from the wall of the home. The windows are commonly joined at 30- or 45-degree angles.
Beveled Exterior: An angled extension from the frame that adds an aesthetically-pleasing dimension to the exterior of the window.
Bow Window: An angled combination of windows in 3-, 4- or 5-lite configurations. The windows are attached at 10-degree angles to project a more circular, arced appearance.
Butyl: A rubber material that seals the glass to the spacer, creating an airtight and water-tight IG unit. Butyl has the lowest gas permeability of all rubbers.
Cam Lock and Keeper: The mechanisms which pull the sash together when placed in the locked position.
Capillary Tubes: Small hollow tubes which penetrate the spacer system of an insulating glass unit. They allow pressure equalization between manufacturing locations, shipping, and installation locations. Since the insulating glass unit is not permanently sealed, the air space cannot be filled with Argon gas.
Casement Window: A window with a side-hinged sash that opens outward for ventilation.
Celcon® Rollers: Self-lubricating rollers that are found in Slider windows and patio doors, that will not mar and are corrosion resistant.
Center of Glass U- and R-values: The U- and R-values measured from the center of the glass to 2-1/2" from the frame.
Condensation Resistance Factor: A measure of the effectiveness of a window or glazing system to reduce the potential for condensation. The higher the condensation resistance factor, the more efficient the window and glazing system.
Conduction: Energy transfer from one material to another by direct contact.
Convection: Heat transfer by currents that flow from a warm surface to a colder one.
Coved Exterior: An arced extension from the frame that adds an aesthetically-pleasing dimension to the exterior of the window.
Dead-air space: The space between the panes of glass of an I.G. Unit.
Deadlite: A piece of glass or IGU with a sash profile around it; not set within the main frame of a window unit.
Denny Clip™ Pivot System: An exclusive hinge-type system used on hung windows. This system attaches the sash to the balance, creating perfect alignment between the sash and frame, while allowing the sash to tilt inward for cleaning.
Desiccant: A material used in insulating glass to absorb water vapor which causes fogging.
Double Hung Window: A window that has two operable sash which slide vertically.
Double-strength Glass: Glass with a thickness of approximately 1/8".
Dry glazing: An alternative method of placing glass in a door or window. No glazing mastic is used. Dry glazing is recommended whenever reflective coatings are glazed to first surface.
Dual-durometer: An elastomeric material with two different degrees of hardness.
Egress Code: The code that requires a minimum opening of a window for persons to exit or firefighters to enter a building.
ENERGY STAR®: ENERGY STAR® is an independent U.S. government program establishing a standard set of guidelines to recognize the energy efficiency of various products. ENERGY STAR® guidelines are used in conjunction with a variety of building materials, including windows and patio doors. Over the past ten years, ENERGY STAR® guidelines have helped double the efficiency of windows they endorse.
Extruded screen frame: Different from a Rollformed frame, this frame is pressed through a form or die.
Fusion-welded: The process of joining materials by melting them together with extreme heat (over 500ºF), resulting in the materials uniting into a one-piece unit.
Geometric: Specially designed windows classified as either Straight line Geometrics such as rectangles, triangles, trapezoid, octagons, pentagons, etc., or Radius Geometrics which include half-rounds, quarter-rounds, full-rounds, sectors, ellipses, eyebrows, etc.
Glass: An inorganic transparent material composed of sand (silica), soda (sodium bicarbonate), and lime (calcium carbonate) with small quantities of alumina, boric or magnesia oxides. Available Styles: Clear, Bronze, Grey and Tinted.
Glazing: The process of sealing the glass to the sash.
Glazing Bead: A strip of vinyl which surrounds the edge of the glass and holds it in place in conjunction with other sealants.
Grids: Decorative horizontal or vertical bars installed between the glass panes to create the appearance of the sash being dividing into smaller lites of glass.
Head: The horizontal top portion of the main frame.
Head expander: A vinyl shape cut the width of a product and placed on the head, fitting over it snugly. This piece is used as a filler to expand or lengthen the unit from the head and take up the gap in the opening between the unit and the opening in the unit.
Hook accessory: Accessories that snap to the hook frame and provide easy installation.
Hopper: A window with a bottom-hinged sash that opens inward for ventilation.
I.G. Unit (Insulating Glass Unit): Two or more lites of glass separated by a spacer and hermetically sealed at the glass edges.
Intercept® Spacer System: Spacer system using a U-channel design to reduce the number of conduction paths.
J-channel: Integral extension on the outside of a new construction window that eases installation on siding applications.
Jamb: Vertical sections of the main frame.
Keeper Rail: The horizontal section of the sash where the keeper is attached.
Keeper Stile: The vertical section of the sash where the keeper is attached.
KeepSafe® glass: Specially designed glass where two panes of glass are bonded to a durable plastic interlayer, providing increased safety, UV protection and noise reduction. If the window gets broken the glass will adhere to the plastic interlayer; preventing glass fallout in the home. KeepSafe® is a registered trademark of Monsanto.
Krypton Gas: An inert, odorless, colorless, tasteless, non-toxic gas which is about 12 times more dense than air. It is used to replace air between the glass panes to reduce temperature transfer and deter convection. Used when a higher performance is desired than that produced with Argon gas.
Laminated Glass: Two or more pieces of glass bonded together over a plastic interlayer.
Lap-Lok® Meeting Rail: A patented meeting rail which overlaps and interlocks both sash.
Lift Handle: A handhold for raising and lowering the sash. Handle implies that the handhold is not continuous across the sash.
Lift Rail: A handhold for raising and lowering the sash. Rail implies that the handhold is continuous across the sash.
Lite: A unit of glass in a window.
Lock Rail: The horizontal section of the sash where the cam lock is attached.
Lock Stile: The vertical section of the sash where the cam lock is attached.
Low E (Emissivity) Glass: Glass with a transparent metallic oxide coating applied onto or into a glass surface. The coating allows short-wave energy to pass through but reflects long-wave infrared energy which improves the U-value.
Main Frame: The head, sill and jambs sections of a window.
Mechanically Fastened Frame: Refers to frames fastened with screws.
Meeting Rail: The horizontal sections of a pair of sash that meet when the sash are closed.
Meeting Stile: The vertical section of a pair of sash that meet when the sash are closed.
Mesh: Fabric made of either fiberglass or aluminum, used in the making of screens.
Mullion: A vertical or horizontal connecting unit between two or more windows.
Nailing Fin: An extrusion attached to the main frame of a window used to secure the unit to the rough opening.
Obscure Glass: Glass that has been made translucent instead of transparent.
Oriel: A window with the meeting rail located off center of the frame. Most oriels have a 60/40 configuration.
Overlapping and Interlocking Meeting Rail: A patented meeting rail which overlaps and interlocks both sash.
Patio door: A glass door that slides open and close on adjustable tandem rollers. Available in 2- or 3-lite configurations with the operable panel available in any position.
Picture Window: A window that has no moveable sash.
Pivot Alignment System: An exclusive hinge-type system used on hung windows. This system attaches the sash to the balance, creating perfect alignment between the sash and frame, while allowing the sash to tilt inward for cleaning.
Power Seal Spacer System or True-dual Seal: A high-performace spacer system based on four independant designs featuring a U-channel Intercept spacer dual-sealed with urethane adhesive and a hot melt butyl and an additional desiccant matrix within the spacer cavity. Pull Handle; A handhold for sliding the sash back and forth. Handle implies that the handhold is not continuous across the sash.
Pull rail: A handhold for sliding the sash back and forth. Rail implies that the handhold is continuous across the sash.
Pull Stile: A handhold for sliding the sash back and forth. Stile implies that the handhold is continuous across the sash.
R-value: Resistance a material has to heat flow. The higher the R-value, the greater the resistance.
Radiation: Wave energy transmitted directly from one object to another through the atmosphere or through transparent or translucent materials. The energy radiated is either transmitted, absorbed, reflected or a combination of all three.
Rail: The horizontal sections of the sash.
Raised Exterior: An angled extension from the frame that adds an aesthetically pleasing dimension to the exterior of the window.
Relative Humidity Condensation Point: The relative humidity level at which visible water vapor or other liquid vapor begins to form on the surface of the sash or frame, based on an inside temperature of 70E F and an outside temperature of 0E F. The higher the percentage, the more moisture the air can hold before condensation will occur.
Rollformed Screen Frame: A method of fabrication in which a flat (usually metal) material is placed on a machine where the material is formed into shape using differently shaped rollers and pressure.
Sash: The part of the window which contains the glass.
Sash Alignment System: An exclusive hinge-type system used on hung windows. This system attaches the sash to the balance, creating perfect alignment between the sash and frame, while allowing the sash to tilt inward for cleaning.
Secure Nest™ Cam Lock: The mechanisms, which draw the sash together into a tight formation with an interlocking cam inside a recessed keeper.
Secure Seal™ meeting rail: An overlapping/interlocking meeting rail.
Shading Coefficient: The ratio of solar heat that is transferred through a glazing material relative to the solar heat transferred through 1/8" clear glass. The lower the number the more efficient the window is at reducing solar heat gain.
Sill: The horizontal, bottom section of the main frame.
Sill Extender: An extrusion that is attached to the bottom of the window to cover the gap between the sill and the rough opening.
Simonton Sill®: An exclusive triple-stepped, sloped sill design.
Single Hung: A window in which one sash slides vertically and the other sash is fixed.
Single-strength Glass: Glass with a thickness of approximately 3/32".
Slider Window: A window in which the sash move horizontally. Sliders are available in a 2- or 3-lite configuration, with the 3-lite having operable end vents.
Sloped sill: The sill of the window that has a downward slope to the outside. This sill has sufficient degree of slope to aid in water runoff.
Solar Heat Gain: The percentage of heat gained from both direct sunlight and absorbed heat. The smaller the number, the greater the ability to reduce solar heat gain.
Spacer: Material placed between two or more pieces of glass in order to maintain a uniform width between the glass, and prevent sealant distortion.
Stepped Sill: An exclusive triple-stepped, sloped sill design.
Stile: The vertical sections of the sash.
Stucco Fin: An extrusion used in stucco home installations that is attached to the main frame to create a smooth, finished look for both the window and the stucco.
Super Sensor Glass™: A superior energy efficient glass package that offers 1" double strength glass, a solid silicone foam spacer and an optimum ¾" airspace filled with Argon gas.
Super Spacer®: A solid silicone foam spacer covered with Mylar. It is sealed to the edge of the glass and then sealed with butyl for greater energy efficiency.
Tape Glazing: Two-sided tape used to secure and seal the glass to the sash.
Tempered Glass: Glass with a surface compression of not less than 10,000 psi, or an edge compression of not less than 9,700 psi. When broken, the glass breaks into pebbles instead of shards.
Terrained Super Spacer®: A solid silicone foam spacer covered with Mylar, with a corrugated, terrained surface appearance. It is sealed to the edge of the glass and then sealed with butyl for greater energy efficiency.
Tilt Latch: Mechanism that unlocks the sash and allows it to tilt in from the main frame.
Tilt-in/lift-out sash: A sash that can be tilted to the interior and removed for cleaning and is manufactured by welding.
Total Unit U- and R-values: The U- and R-values of the window calculated from the average of the center of glass, edge of glass and frame U- and R-values. It is the reciprocal of the R-value.
Tri-durometer: An elastomeric material with three different degrees of hardness.
U-value: Amount of heat transferred through a material. The lower the U-value, the slower the rate of heat flow and the better the insulating quality.
UV Block: The percent of ultraviolet rays blocked from being transmitted through the glass. The higher the number the lower the percentage of ultraviolet rays transmitted through the window.
Vent-lok: Latch mechanism on the interior face of the sash which retains the window in a partially open position for ventilation.
Visible Light Transmittance: The percentage of light that is transmitted through glass in the visible light spectrum (380 to 720 nanometers). The higher the number the higher the percentage of visible light transmitted through the window.
Weatherstripping: Material used to form a weather-resistant seal around operable sash.
Weep flaps: A weep hole that is covered with vinyl flap that allows water to escape, while keeping insects out.
Weep Holes: Small openings designed to allow water to escape that might otherwise accumulate in a window's sill.
Weep Slots: Slots or holes in the sill (bottom) member of the sash frame that provides an outdoor release of infiltrated rainwater.
Wet Glazing: A silicone-based substance used to secure and seal the glass to the sash.
Wood blocks: Pieces of plywood that come in different thickness, depending on the depth of the hook of the frame. They are used to make the window flush with the opening it is filling. They are also used to assist in pre-mulling windows together and give the screw more to bite into when joining the windows.
Wood jamb strips: Strips of wood that run along the jamb used to shim up the window.

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