Glossary
Habitable Space
Building space intended for continual human occupancy. Such space generally includes areas used for living, sleeping, dining and cooking, but does not generally include bathrooms, toilets, hallways, storage areas, closets, or utility rooms.
Heat Transfer
The science of estimating the amount, rate, and direction of heat flow; an inexact science bounded by the Laws of Thermodynamics.
Heating Degree Day (HDD)
A form of degree-day used as an indication of fuel consumption; in United States usage, one heating degree-day is given for each degree that the daily mean temperature departs below the base of 65°F. The number of degrees that a day's average temperature is below 65Fahrenheit (18Celsius), the temperature below which buildings need to be heated.
HERS
Abbr. Home Energy Rating System. Developed by RESNET, DOE and others for rating buildings for energy efficiency.
HRV
Abbr. Heat Recovery Ventilator- This device bring fresh, outside air into a home while simultaneously exhausting stale indoor air outside. In the process of doing this, an HRV removes heat from the exhaust air and transfers it to the incoming air, pre-heating it.
Humidity
the water vapor component of moist air.
HVAC
Abbr. Heating Ventilation and Air Conditioning
Hydrophilic
A term used to describe a surface or material that attracts and holds water, transiently bonding with it via hydrogen bonds. Liquid water on a hydrophilic surface will tend to absorb into the material—i.e., "wettable."
Hydrophobic
Materials that do not attract liquid water, they will force liquid water to form beads on their surface, act as capillary breaks and are non-Materials that do not attract liquid water, they will force liquid water form beads on their surface, act as capillary breaks and are non-hygroscopic.
Hydrostatic
A term used to describe pressures developed by a non-moving fluid (typically water, in our cases), such as the buildup of subsurface water against a foundation wall.
Hygroscopic
Materials that interact with water vapor by adsorbing water vapor as a function of the relative humidity of the surrounding air.