Glossary

Acronyms

SEER

— Seasonal energy efficiency ratio – A measurement of energy efficiency for central air conditioners. The SEER is computed by dividing cooling capacity, measured in Btuh, by the watts. (See also Energy Efficiency Ratio.)

EER

— Energy efficiency ratio – A measurement of energy efficiency for room air conditioners. The EER is computed by dividing cooling capacity, measured in British Thermal Units per hour (Btuh), by the watts of power.

AFUE

— Annual fuel utilization efficiency – A laboratory-derived efficiency for heating appliances which accounts for chimney losses, jacket losses, and cycling losses, but not distribution losses or fan/pump energy.

ASHRAE

— American Society of Heating, Refrigerating and Air Conditioning Engineers – Sponsors research and develops standards documents that help establish acceptable levels of performance for buildings and mechanical equipment.

ORNL

— Oak Ridge National Laboratory – Under contract to the U.S. Department of Energy (DOE), its building research facility performs thermal testing on full size building components. The results of the lab’s research are published and available to the public for a nominal price.

USGBC

— U.S. Green Building Council: Developers of the LEED program.

Glossary of Terms

$/100 CFM50

— The estimate of the heating cost (or the value of a reduction) of 100 CFM50. Depends upon climate, fuel cost, system efficiency, and payback assumptions. A very useful number for determining the cost-effectiveness of air sealing.

“c”

— The flow rate, in CFM, with a 1 Pa difference.

“n”

— The slope of the leakage curve. A rough indicator of the average size of the individual holes. The higher the number, the smaller the holes. Many houses tend to be between 0.6-0.7. Less than 0.6 indicates the existence of major large holes, above 0.7 smaller holes tend to dominate.

ACH

— Air changes per hour, a description of leakage as compared to volume. The number of times each hour an amount of air equal to the volume of the building leaks out. Used for both blower door measurements and estimates of normal flows.

ACH50

— Air changes per hour at a 50 Pa pressure difference. Not to be confused with natural ACH. Houses with less than 5-6 ACH50 are quite tight and those over 20 are quite leaky. Can be misleading in very small or large houses.

air-dried lumber

— Lumber that has been piled in yards or sheds for any length of time; in the U.S, the minimum moisture content of thoroughly air- dried lumber is 12 to 15 percent, and the average is somewhat higher; in the southern states, air-dried lumber may be no lower than 19 percent.

air space

— The area between insulation facing and interior or exterior wall coverings; normally a one-inch air gap.

backdrafting

— Continuous spillage of combustion gases from a combustion appliance.

brownfield

— An abandoned or underused industrial or commercial property or neighborhood where expansion or redevelopment is complicated by real or perceived contamination.

building cavities

— The spaces inside walls, floors, and ceilings between the interior and exterior sheeting.