kbody. The ideal, perfect emitter and absorber of thermal radiation. It emits radiant energy at each wavelength at the maximum rate possible as a consequence of its temperature, and absorbs all incident radiance. BOCA. Building Officials and Code Administrators. Bottom rail. The bottom horizontal member of a window sash. Bow window. A rounded bay window that projects from the wall in an arc shape, commonly consisting of five sashes. Brick molding. A standard milled wood trim piece that covers the gap between the window frame and masonry. Btu (B.T.U.). An abbreviation for British Thermal Unit, the heat required to increase the temperature of one pound of water one degree Fahrenheit. Back to top   C Casement. A window sash that swings open on side hinges: in-swinging are French in origin; out-swinging are from England. Casing. Exposed molding or framing around a window or door, on either the inside or outside, to cover the space between the window frame or jamb and the wall. Caulking. A mastic compound for filling joints and sealing cracks to prevent leakage of water and air, commonly made of silicone, bituminous, acrylic, or rubber-based material. CFM. Cubic Feet per Minute. Check rail. The bottom horizontal member of the upper sash and the top horizontal member of the lower sash which meet at the middle of a double-hung window. Clerestory. A window in the upper part of a lofty room that admits light to the center of the room. Composite frame. A frame consisting of two or more materials for example, an interior wood element with an exterior fiberglass element. Condensation. The deposit of water vapor from the air on any cold surface whose temperature is below the dew point, such as a cold window glass or frame that is exposed to humid indoor air. Conduction. Heat transfer through a solid material by contact of one molecule to the next. Heat flows from a higher-temperature area to a lower-temperature one. Convection. A heat transfer process involving motion in a fluid (such as air) caused by the difference in density of the fluid and the action of gravity. Convection affects heat transfer from the glass surface to room air, and between two panes of glass. CRF. Condensation Resistance Factor. An indication of a window’s ability to resist condensation. The higher the CRF, the less likely condensation is to occur. Based on AAMA standard. Back to top   D Degree day. A unit that represents a one-degree Fahrenheit deviation from some fixed reference point (usually 65° F) in the mean, daily outdoor temperature. See also heating degree day. Desiccant. An extremely porous crystalline substance used to absorb moisture from within the sealed air space of an insulating glass unit. Dewpoint. The temperature at which water vapor in air will condense at a given state of humidity and pressure. Divide

Metal Frames with Thermal Break Aluminum window frames are light, strong, durable, and easily extrud

Whole Window Properties – Metal Frames with Thermal Break

There is no simple rating or absolute guarantee of the durability

These aspects of window durability deserve special attention: Fr

ducts heat. Condensation and even frost can form. Thermal breaks reduce conduction and improve condensation resistance. The durability of thermal breaks varies by type and quality. Wood: Easy to repair and maintain. Intrinsically susceptible to rot, but many new wood windows are protected by a durable exterior finish or cladding. Cladding should prevent moisture from forming underneath. Composite: New wood/polymer compo

failure and gas loss, insulating glass in ENERGY STAR windows must be certified through recognized programs. IG certification requires that sample IG units undergo accelerated weathering over extended time periods to determine whether the IG unit can withstand extreme temperature swings, high humidity and UV radiation without failure. IG certification also requires that the manufacturer implements in-house quality assu

orth the investment. After some years, any kind of weatherstripping should be inspected in case it warrants to be replaced. Organic felts age fairly quickly, and all felts absorb moisture, reducing their effectiveness. Brush or wiper type weatherstripping eventually gets matted down like a carpet that has had too much traffic. Metal strips are easily dented or bent. Plastics and rubber can become brittle or sticky. Neve

l building code should be reviewed to determine requirements for wind load resistance and water penetration resistance. Organizations such as the American Architectural Manufacturers Association exit disclaimer (AAMA) and the Window and Door Manufacturers Association exit disclaimer (WDMA) provide information on these standards, as do local building departments. Windows can be tested for their structural strength, resis

n indicator of the reliability of the window and its manufacturer. Durability may vary with location; for example, some materials are degraded by salt near the ocean. These aspects of window durability deserve special attention: •    frame and sashes •    insulating glass seals •    weatherstripping •    local requirements for structural integrity

ducts heat. Condensation and even frost can form. Thermal breaks reduce conduction and improve condensation resistance. The durability of thermal breaks varies by type and quality. Wood: Easy to repair and maintain. Intrinsically susceptible to rot, but many new wood windows are protected by a durable exterior finish or cladding. Cladding should prevent moisture from forming underneath. Composite: New wood/polymer comp

l failure and gas loss, insulating glass in ENERGY STAR windows must be certified through recognized programs. IG certification requires that sample IG units undergo accelerated weathering over extended time periods to determine whether the IG unit can withstand extreme temperature swings, high humidity and UV radiation without failure. IG certification also requires that the manufacturer implements in-house quality as

ady Home using either the Prescriptive Path or Performance Path. See the Program Requirements Document for information Window Performance Information All fenestration shall meet or exceed ENERGY STAR requirements.* *Windows shall meet the applicable ENERGY STAR Window Product Criteria based on the following schedule:

, which must follow ENERGY STAR Windows Eligibility Criteria Version 6.0 for projects permitted after 8/31/2016

cation where triple glazed window assemblies with thermal breaks/spacers between the panes are used, such windows are deemed to meet this requirement even in the absence of an ENERGY STAR certification. *Fenestration shall meet the applicable ENERGY STAR Windows Eligibility Criteria for U and

45 degrees of true South and directly coupled to thermal storage mass that has a heat capacity > 20 btu / ft3x°F and provided in a ratio of at least 3 sq. ft. per sq. ft. of South facing fenestration. Generally, thermal mass materials will be at east 2 in. thick.