Window Efficiency Terminology

R-Value - R-value is a measurement of heat resistance. It is the inverse of the U-value, so the higher the R-value the better the window resists heat transfer.

U-Value- U-value is a measurement of heat flow. The lower the U-value, the more slowly the window transfers heat in and out of your home.

Glazing Technology

Low-emissivity (Low-E) consists of a thin layer of metal oxide applied to the exterior face of the interior glazing in a double-glazed windows. This coating allows sunlight to pass through, but blocks heat from escaping. A double-glazed low-E window provides similar insulation value to that of a triple-glazed unit, but costs less and weighs less. Low E glazing fliters out the sun's ultraviolet (UV) rays, which can fade furnishings; and can reduce condensation on the window by keeping the indoor surface of the glass and frame warmer.

Tinted glazing - tinted glass and tinted window films reduce the amount of the sun's heat entering the building. The shading coefficient (SC) of a window is the amount by which the window reduces heat gain. The lower the shading coefficient, the less solar heat is admitted.

Weatherstripping: Weatherstripping is a component of an operable window, and provides a seal between the window-frame and the operable sash. It is used to prevent air leakage, and the better the weatherstripping, the better the window performance.

Condensation: Condensation is the buildup of water droplets on a cold window pane. This can occur on the inside of single pane windows, and in between the panes of multiple pane windows. Condensation on single pane windows can damage windowsill and wall surfaces if extensive. Condensation between the panes of multiple pane windows indicates a problem with the seal between the panes.

Thermal break: Thermal break is a material that doesn't transmit heat well, such as plastice, sandwiched inside the metal parts of the frame. This reduces the heat being transferred through the frame. Thermal breaks can be used in the spacer between panes of glass in multi-pane windows as well as in main body of the frame.

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Water Heater Terminology

Storage capacity - the gallons of hot water a storage water heater can hold in the storage tank.

Water Heater Temperature - water heaters have a thermostat which controls the temperature of the water. You can save money by lowering the temperature of your water heater to 120°F. If you have a dishwasher without a heating element, you should leave your thermostat on the "Medium" setting 140°F.

Peak-hour demand - the maximum water usage, in gallons/hour, during the time of day when your family is likely to use the greatest amount of hot water.

First-hour rating - the ability of a water heater to meet peak-hour demands. It measures how much hot water the heater will deliver during a busy hour. The first-hour rating accounts for the effects of tank size, and how quickly cold water is heated.

Standby losses - storage water heaters constantly loose heat by conduction through the wall of the tank, and through the first few feet of water pipes. To reduce standby losses, insulate the tank, the first two feet of the cold water inlet pipe, and the first three feet of the hot water outlet pipe.

Energy Factor - the efficiency of storage water heaters is indicated by its Energy Factor (EF), which is based on a average hot water consumption of 64 gallons/day. The higher the EF, the more efficient the water heater.

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Insulation

Cellulose - Cellulose insulation is made from wastepaper, such as used newspaper and boxes. It is shredded into small particles, and chemicals providing resistance to fire and insects are added. Cellulosed insulation is dusty and brown, with flat particules.

Rigid Boards - Rigid boards are fibrous materials or plastic foams pressed or extruded into bard-like forms. These provide thermal and acoustical insulation, strength with low weight, and coverage with few heat loss paths.

Rockwool - Rockwool is dirty grey, but the color ranges through green and brown as well. Rockwool looks like old wool with dark flecks, and you can often find what looks like sand or small pebbles underneath the insulation. Rockwool is spun, like fiberglass, from the slag from refining metals.

Fiberglass - Fiberglass is the most familiar type of insulation. It is spun from molten glass, and is pure white in its virgin state. Additives and binders often color the fiberglass, wich pink and yellow being the most common. Fiberglass comes in rolls, batts and as loose insulation which is blown into place.

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Heating, Ventilation and Cooling Terminlogy

EER- Energy efficiency ratio, this is a measure to assess heat pumps and air conditioners. The higher the EER for your air conditioner or heat pump, the more efficient it is.

SEER - The Seasonal Energy Efficiency Ratio, measures the average cooling efficiency, over the entire cooling season for your air conditioner or heat pump. The hight the SEER rating of a unit, the more energy efficient it is.

Programmable Thermostat - is a thermostat which is designed to adjust the temperature according to a series of prgrammed settings that take effect at different times of the day.

System Capacity - is a measurement of the total amount of heat or cooling your furnace, heat pump or air conditioner can produce in one hour. This amount is reported in Btu/hr on the nameplate of your equipment.

Btu- is the British thermal unit (BTU or Btu) is a unit of energy used in the power, steam generation, and heating and air conditioning industries.

Heat Pump - is basically an air conditioner with a reversible valve that allows it to operate in reverse, removing heat from your house and shunting it outdoors in the summer, and removing heat from outdoor air and shunting it into your house in the winter. Heat pumps are more efficient than other forms of heating.

COP - Coefficient of Performance, COP, is the ratio fo energy input to heating capacity. This is the instantaneous measurement of the heating performance of your heat pump. It is comparable to knowing how many miles per gallon of gasoline your car gets when it is going full speed. You can find the COP on the nameplate of your heat pump.

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Lighting Terminology

Incandescent lamp - is the most common source of light, glass bulbs with a filament inside. Approximately ninety percent of the energy consumed by an incandescent lamp is given off as heat rather than light.

Compact Fluorescent Lamps (CFL) - these fluorescent lamps are small, and are designed to fit in regular lamp sockets. They do not require a special fixture. The electronic ballast-based fluorescents are more efficient, and produce better light than the older magnetic ballast models.

Fluorescent lamp - Fluorescent lamps are up to five times more efficient than incadescent lamps, and last up to twenty times longer. The require a special fixture. Electronic ballast fluorescents are a new efficient improvement over the traditional magnetic ballast fluorescents. Fluorescent lamps are available as straight tubes, U-shaped tubes, circular tubes and compact fluorescent lamps.

Lumen- A lumen is the total amount of light emitted from a source. Lumens are typically used to rate the output of lamps.

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