Helpful Terms

AFUE

This is a percentage measurement of a furnace's heating efficiency. The U.S. government's minimum efficiency level is 78%. The higher the AFUE, the more efficient the furnace. The initials stand for Annual Fuel Utilization Efficiency.

Air Handler

This is the indoor section of a split system. It can be a dedicated air handler, or could be your furnace. Also known as a fan-coil.

AHRI

Air-Conditioning, Heating and Refrigeration Institute. AHRI is an industry trade association that develops standards for measuring and certifying product performance. For instance, AHRI Standard 270 provides guidelines for establishing sound levels for outdoor air-conditioning equipment.

Airflow

The distribution or movement of air.

Ambient Temperature

This is the air temperature (usually the outdoor air temperature) surrounding the equipment.

Bioaerosols

Microscopic living organisms suspended in the air that grow and multiply in warm, humid places.

BTU

British Thermal Unit. This is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. You'll see this measurement when you look at heating and cooling capacities. For example, your dealer may recommend a 75,000 Btu furnace and a 24,000 Btu air conditioner for your home.

Comfort Sync^® A3

Armstrong Air’s most advanced thermostat. Communicates with all the different system components for increased efficiency and control, plus offers the ability to control the system remotely from anywhere in the world.

Condensing Unit

This is the outdoor section of a split-system air conditioning system. You'll know it best as the air conditioner that sits outside your home.

COP

Coefficient Of Performance. A ratio that compares a heat pump system's heating efficiency to that of electric resistance heat. For example, a heat pump system with a COP of 3.0 provides heat at 3 times the efficiency of electric resistance heat. A heat pump's system COP will decrease as outdoor temperatures drop, eventually providing little or no efficiency advantage over electric resistance heat—and that's when your auxiliary heat strips start to heat your home.

Communicating Thermostat

Establishes an electronic connection between all the different heating and cooling system components to optimize overall performance, efficiency and comfort.

Dual Fuel

For even greater efficiency, this heat pump can be paired with a furnace. Called a dual-fuel system, this combination minimizes heating costs by seamlessly alternating between the two energy sources, depending on outdoor conditions.

EER

Energy Efficiency Rating.

ENERGY STAR^®

Products/homes/buildings that earn the ENERGY STAR^® qualification prevent greenhouse gas emissions by meeting strict energy efficiency guidelines set by the U.S. Environmental Protection Agency and the U.S. Department of Energy. To learn more, please visit www.energystar.gov.

GPH

Gallons Per Hour. You might see this rating if you are looking at an oil furnace. In addition to input and output, an oil furnace also has a rating of gallons per hour, the volume of oil a furnace is capable of burning in 60 minutes.

Heat Pump

A unit that both cools and heats your home. A heat pump system can be either a split system or a package system. A heat pump can be used in conjunction with a gas/oil/LP furnace (using the furnace instead of electric resistance heat when temperatures fall below about 35° F) with the addition of a fossil fuel kit.

HSPF

This is a measurement of a heat pump's heating efficiency. The U.S government’s minimum efficiency level is 8.2 HSPF (7.5 HSPF2). The higher the HSPF, the more efficient the heat pump's heating performance. HSPF stands for Heating Seasonal Performance Factor. This rating has been officially replaced by HSPF2.

HSPF2

In 2023, the Department of Energy implemented new, stricter standards for testing the efficiency of heat pump products in heating mode. These more accurately reflect a unit’s performance in real life installations. Like HSPF, the previous rating system, HSPF2 is a measurement of a heat pump's heating efficiency. What’s the difference? Think of it as highway vs. city miles per gallon. Like highways miles per gallon, HSPF represents performance in perfect conditions, whereas HSPF2 reflects performance in real-world installations—similar to stop-and-go traffic in city miles per gallon.

For heat pump split systems, the U.S government’s minimum efficiency level is 7.5 HSPF2. HSPF stands for Heating Seasonal Performance Factor. The higher the HSPF, the more efficient the heat pump's heating performance.

HVAC

HVAC (pronounced either "H-V-A-C" or "aitch-vak") is an acronym that stands for the closely related functions of "Heating, Ventilating, and Air Conditioning."

Mini-Splits System

Mini-splits are heating and cooling systems that allow the temperature in individual rooms or spaces to be controlled. Mini-split systems consist of two main components; an outdoor compressor/condenser and an indoor air-handling unit(s).

Package System

Package units provide both heating and cooling from one unit that is placed outside the home—on the ground, on the roof, or sometimes mounted through the walls of the building. Package units come in several combinations of fuel sources—gas heat/electric cooling; heat pump; electric heat/electric cooling; oil heat/electric cooling.

Remote Access

Armstrong Air’s Comfort Sync thermostat connects to your home’s Wi-Fi network, allowing you to access and adjust your heating and cooling system from anywhere in the world using a smartphone or other web-enabled device.

SEER

This is a measurement of the efficiency of cooling products. The U.S government’s minimum efficiency level is 14 SEER (13.4 SEER2) in northern states, and 15 SEER (14.3 SEER2) for southern and southeastern states. The higher the SEER, the more efficient the cooling product. SEER stands for Seasonal Energy Efficiency Rating. This rating has been officially replaced by SEER2.

SEER2

In 2023, the Department of Energy implemented new, stricter standards for testing the efficiency of cooling products. These more accurately reflect a unit’s performance in real-life installations. What’s the difference? Think of it as highway vs. city miles per gallon. Like highway miles per gallon, SEER represents performance in perfect conditions, whereas SEER2 reflects the performance in real-world installations—similar to stop-and-go traffic in city miles per gallon.

For split systems, the U.S. government’s minimum efficiency level is 13.4 SEER2 in northern states, and 14.3 SEER2 for southwestern and southeastern states. SEER stands for Seasonal Energy Efficiency Rating. The higher the SEER2, the more efficient the cooling product.

Split System

This describes an air conditioning or heat pump system that is split into two sections—an outdoor section and an indoor section. It won't work without the outdoor section plus an indoor section to move the air.

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