HVAC Glossary

AFUE (Annual Fuel Utilization Efficiency)

A percentage measuring how efficiently a furnace or boiler turns fuel into heat over a year. A 95% AFUE furnace delivers 95 cents of heat per fuel dollar.

Air Handler

The indoor unit that circulates conditioned air through your ductwork. It pairs with a heat pump or AC and contains the blower and evaporator coil.

BTU (British Thermal Unit)

A unit of heat energy. HVAC capacity is rated in BTUs per hour — higher BTUs mean more heating or cooling output.

Boiler

A heating system that warms water or steam and distributes it through radiators or baseboard for even, quiet heat.

Condenser

The outdoor unit of an AC or heat pump that releases heat collected from inside your home. It houses the compressor and condenser coil.

Ductless Mini-Split

A heating and cooling system with an outdoor unit and one or more wall/ceiling indoor heads — ideal for additions, sunrooms, or homes without ductwork.

Duct Sealing (Aeroseal)

A process that seals leaks in ductwork to stop conditioned air from escaping, improving comfort and lowering energy bills.

EER / SEER2

Cooling efficiency ratings. SEER2 (Seasonal Energy Efficiency Ratio 2) is the current federal standard for air conditioners and heat pumps — higher is more efficient.

Evaporator Coil

The indoor coil that absorbs heat from your home's air so the system can cool it. Paired with the outdoor condenser coil.

Furnace

A forced-air heating system that burns gas (or uses electricity) to heat air and blow it through ducts. The most common heating type in South Jersey homes.

Heat Pump

An all-electric system that both heats and cools by moving heat rather than burning fuel. Highly efficient and eligible for many NJ and federal incentives.

HSPF2 (Heating Seasonal Performance Factor 2)

The efficiency rating for a heat pump's heating mode. Higher HSPF2 means more heat delivered per unit of electricity.

HVAC

Heating, Ventilation, and Air Conditioning — the systems that control your home's temperature, airflow, and air quality.

Indoor Air Quality (IAQ)

The healthfulness of the air inside your home, affected by filtration, humidity, ventilation, and contaminants. Improved with purifiers, filters, and humidity control.

Load Calculation (Manual J)

An industry-standard calculation of how much heating and cooling a home needs, based on size, insulation, windows, and climate. It ensures a system is sized correctly — not too big or small.

MERV Rating

Minimum Efficiency Reporting Value — how well an air filter captures particles. Higher MERV traps smaller particles, but must match what your system can handle.

Refrigerant

The fluid that absorbs and releases heat as it cycles through your AC or heat pump. Newer systems use lower-impact refrigerants.

Short Cycling

When a system turns on and off too frequently, wasting energy and wearing out components. Often a sign of an oversized unit or a service issue.

Smart Thermostat

A programmable, internet-connected thermostat that learns your schedule and optimizes comfort and energy use, often controllable from your phone.

Tonnage

A measure of cooling capacity. One ton equals 12,000 BTU/hour. Most homes use systems between 1.5 and 5 tons, sized by a load calculation.

Two-Stage / Variable-Speed

Equipment that can run at multiple output levels instead of just on/off, providing steadier comfort, quieter operation, and better efficiency.

NATE Certification

North American Technician Excellence — the leading independent certification verifying an HVAC technician's real-world knowledge and skill.

Zoning

Dividing a home into independently controlled comfort zones using dampers or multiple units, so you only heat or cool the spaces you're using.

Have a term you'd like explained? Ask our team — we're happy to translate the technical stuff into plain English.