ABS: acrylonitrile butadiene styrene. A common thermoplastic made when styrene and acrylonitrile is polymerized in the presence of polybutadiene. It is used to make drain, waste and vent pipes for the house plumbing, as well as many other items from Legos to the “ink” in 3d printers.


aerator: a screened attachment that is screwed on to the end of a faucet. By mixing air into the flowing water, a consistent stream is produced, reducing water consumption the likelihood of splashing.


AFCI: Acronym for Arc Fault Circuit Interrupter. A circuit breaker or receptacle that has the ability to shut off the power to its circuit if it senses hazardous electrical arcing along its circuit. Click here to see where AFCI protection is required. As your home inspector is concerned with the safety of your home, he/she will typically make recommendations to increase …

Air Admittance Valve

air admittance valve: a spring controlled plumbing device, typically installed in air admit valve locations that are difficult to serve with a traditional style of plumbing vent. The device opens and closes in response to changes in pressure in the drain lines, allowing air to enter the drain when needed, and sealing the drain to keep air from otherwise escaping.

Air Gap

air gap: typically defined as the vertical space between a water outlet (such as the end of a faucet) and the highest point (flood rim) of a fixture (such as a sink). In home inspections, the air gap is commonly defined as an opening on the waste line, above the flood rim of the sink, intended to keep dirty drain water …

Aluminum Wire

aluminum wire: introduced in the mid 1960’s as a cheaper alternative to copper wiring, the solid version of this wire may present safety and insurance concerns for homeowners


amperage: a measure of electrical current flow; the number of electrons flowing past a certain point in a given amount of time

Anti-tip bracket

Metal bracket designed to prevent free-standing stoves from tipping over, especially if a child attempts to stand on an open over door. These brackets screw into the wall behind the stove and the rear leg of the stove slides into the opening in the bracket. These brackets are included in the installation packet of all free-standing stoves.

Appliance Vent

appliance vent: a pipe, typically traveling through the roof of the home, intended to allow the flow of air/gases to and from combustion appliances. They may provide a source of combustion air for the appliance and/or provide a discharge for gases of combustion to safely exit the home.

Apron Flashing

apron flashing: an area of flashing installed at the intersection between a roof area and a vertical element, such as a wall, chimney or other roof section