FAQ

Measures the amount of fuel converted to space heat in proportion to the amount of fuel entering the furnace. This is commonly expressed as a percentage. A furnace with an AFUE of 90 could be said to be 90% efficient. AFUE includes any input energy required by the pilot light but does not include any electrical energy for fans or pumps.

Any material that restricts air flow. In wall assemblies, the exterior air barrier is often a combination of sheathing and either building paper, house wrap or board insulation. The interior air barrier is typically gypsum board.

Insulation that is typically manufactured out of fiberglass into ‘blankets’ sized for typical framing bays and manually fitted into place. They require extra diligence to ensure no gaps, voids, compression, or misalignment in framing bays that do not fit standard framing dimensions or include wiring and piping.

This diagnostic tool is designed to measure the airtightness of buildings and to help locate air leakage sites. The airtightness of a building is useful knowledge when trying to increase energy conservation or decrease indoor air pollution, or control building pressures.

Insulation typically made from fiberglass or cellulose that is blown into construction assemblies dry or wet that inherently fills the entire framed assembly to eliminate any gaps, voids, compression, or misalignment. Typically found in attics.

The outer shell, or the elements of a building, such as walls, floors, and ceilings, that enclose conditioned space. A vital piece in HVAC load calculations.

Insulation installation condition where the full thickness is reduced, resulting in increased density and reduced air pockets that drive thermal resistance. This undermines the effective R-value of the insulation.

The drawings (plans) and written specifications that describe construction requirements for a building. Our team works with contractors, designers, builders, engineers, and more to develop an ideal HVAC system for each project.

As used with thermal bypass, this refers to airflow that occurs in gaps between insulation and the air barrier due to temperature differences in and across the gap, resulting in a stack effect or driving forces from more to less heat.

A sealed ventilation system for combustion appliances that draws combustion air from outside the structure and vents combustion exhaust outside the structure. These systems may be combined with power vent exhausts. See Power Vent and Sealed Combustion.

Diagnostic tool designed to measure the airtightness of ductwork and to help locate air leakage sites. Duct leakage can increase heating and cooling costs over 30% and contribute to comfort, health, and safety problems. Our team specializes in Manual D duct designs.

A standardized measurement of the annual energy efficiency of water heating systems. It is the annual hot water energy delivered to a standard hot water load divided by the total annual purchased hot water energy input in consistent units. The resultant EF value is a percentage. EF is determined by a standardized U.S. Department of Energy (DOE) procedure.

The quantity of onsite electricity, gas, or other fuel required by the building equipment to satisfy the building’s heating, cooling, hot water, or other loads or any other service requirements (lighting, refrigeration, cooking, and so on).

A site inventory and descriptive record of features impacting the energy use in a building. This includes, but is not limited to: all building component descriptions (locations, areas, orientations, construction attributes, and energy transfer characteristics), all energy-using equipment and appliance descriptions (use, make, model, capacity, efficiency, and fuel type), and all energy features.

A home, certified by the U.S. Environmental Protection Agency (EPA), that is at least 30% more energy efficient than the minimum national standard for home energy efficiency as specified by the 1992 MEC, or as defined for specific states or regions. ENERGY STAR is a registered trademark of the EPA.