October 16, 2017


Glossary of the most common terms used by Comfort Pro Heating and Cooling technicians.

Let us know if you have any questions..!

HVAC/R – Heating Ventilation Air Conditioning Refrigeration 🙂

BTU – BTU stands for British thermal unit, which is a unit of heat energy. One Btu is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

Capacity – The ability of a heating or cooling system to heat or cool a given amount of space. For heating, this is displayed in BTU/h. For cooling and is normally given in tons.

Heat Pump – An air conditioning system that can cool AND heat using the same refrigeration system. Amazing! Has a mechanical device that can reverse the flow of the refrigerant (Freon) and thereby change from cooling to heating. Heat pumps come in the form of a packaged system, split system or even a duct-free system. The term “Heat Pump” is often wrongly used when talking about a packaged unit.

Packaged unit – Everything in one big metal box. Outdoor coil (condenser), indoor coil (evaporator), outdoor fan, an indoor fan, control system, gas burners (if Gas/Electric) and even resistive backup “heat strips” can be found inside the big metal box outside your house. Often it comes with straight A/C, Heat Pump, Gas/Electric or even Dual Fuel versions. Packaged units are often mistakenly called a “Heat Pump” even though they may not, in fact, be a Heat Pump, but a Gas/Electric packaged A/C. Who knew!

Duct-free / Duct-less / Mini Split – No duct tape needed! A two-piece air conditioning system which has an outdoor unit and an indoor unit (often mounted high on a wall) which are connected via refrigeration lines. Comes in straight A/C (cooling only) or Heat Pump models. Very efficient use of solid-state electronic technology gives most duct-free systems fully variable capacity which in turn allows the unit to provide just the right amount of heating or cooling and makes them thereby very energy efficient. Widely used all around the planet, Europe, Asia, even South America and on the moon (just kidding). Here in the US, however, ductless systems are considered exciting new technology with a market growth of 25% in 2013.

AFUE – Annualized Fuel Utilization Efficiency is a measure of your furnace’s heating efficiency. Specifically, it is the ratio of annual output energy compared to annual input energy. The higher the AFUE percentage is, the more efficient the furnace. The minimum percentage established by the DOE for furnaces is 78%.

SEER – Seasonal Energy Efficiency Ratio scheme implemented by the AHRI (Air-conditioning, Heating & Refrigeration Institute) to be able to measure different air conditioning systems against each other in the amount of cooling they produce per kW of electricity used. The EPA (Environmental Protection Agency) currently requires HVAC contractors to install new equipment with a minimum rating of 13 SEER and every SEER point higher saves you approximately 5 – 7% on your annual cooling electricity bill.

ENERGY STAR® – An EPA designation attached to HVAC equipment to identify models that meet EPA guidelines for high-efficiency performance that exceed standard government minimums. Manufacturers and retailers place the ENERGY STAR® label on those models that meet the labeling criteria. The label helps consumers identify those products that will save money and energy.

Freon – fascinating stuff. Freon is a generic term used for the chemical that is the refrigerant in an air conditioning or Heat Pump system that transfers heat from one place to another, i.e., indoors to outdoors or vice versa. The compressor in the outdoor unit is what moves this chemical through the coils and refrigeration lines. R-22 (Refrigerant #22) used to be the most commonly used in residential and light commercial HVAC until the EPA decided to make us switch to R-410a in the year 2010. Since then, all new HVAC equipment has to either be pre-charged with R-410a or be shipped empty, and the proper refrigerant has to be added on site. One has to hold a special EPA certificate to buy and handle most refrigerants. Unauthorized handling of refrigerants carries severe penalties. Weird fact – Propane gas and water are refrigerants…


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