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When trying to read more about buying or repairing your furnace or air conditioner, there are a lot of heating and cooling terms that may be difficult to understand.

While the industry language isn’t something you’ll use every day, understanding the basic definitions and acronyms can help you optimize your home comfort system. Whether it’s to replace your system, the following terms can help. Here are 17 HVAC definitions that you need to know: AFUE – Annual Fuel Utilization Efficiency. Rates the efficiency of your gas furnace in converting fuel to energy. A 90 rating means that approximately 90% of the fuel is utilized to heat your home while 10% escapes as exhaust – after factoring in all annual losses. BTU – British Thermal Unit. The amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. This measures the amount of heat a furnace will add or an air conditioner will remove from your home. CFM – Cubic feet per minute. This is a standard airflow measurement, a typical system requires 400CFM per ton of air conditioning. Ducts – These are the big metal air highways routed throughout many homes. They’re used for central air systems to push the conditioned air into each room throughout the house. Ductless – Now that you know what a duct is, ductless is pretty self-explanatory. These are systems that don’t use ducts to distribute the air throughout your home. Freon (Refrigerant) – Trade name of R-22 chlorofluorocarbon (CFC). This is used as refrigerant in air conditioners and refrigerators. Furnace Switch – A furnace switch is a switch near your furnace that controls the power. We often find they’re turned off by accident when people assume it’s a light switch, this can cause confusion as to why your furnace wouldn’t be working.ii HEPA – High Efficiency Particulate Air. HEPA filters capture up to 99.97% of particles as small as 0.3 microns. HVAC – Heating, Ventilation and Air Conditioning. This is our core business! IAQ – Indoor Air Quality. This is about more than just temperature; this is where filters, HRVs/ERVs, humidifiers and air purifiers are used. IESO – Independent Electricity System Operator. This is an organization that offers incentives for upgrading your system to a high-efficiency unit. Inverter – Used to control the speed of the compressor motor to drive variable refrigerant flow in an air conditioning system to regulate the conditioned-space temperature. MERV – A rating of air filters based on the minimum particle capture size. A rating of 1 is the least efficient, with 16 being the most efficient. Click here to find out how you can use MERV to benefit your system. Micron – One millionth of a meter. Puron – Trade name of new industry standard R-410A environmentally friendly refrigerant developed as replacement for R-22 Freon. SEER – Seasonal Energy Efficiency Ratio. A measure of an air conditioner’s efficiency. The higher the SEER rating the better. 13 SEER’s will provide 13 BTU’s of cooling for every Watt of energy consumed after factoring in seasonal losses. Ton – A unit of measurement used for determining cooling capacity. One ton is the equivalent of 12,000 BTU’s per hour or the cooling effect of one Ton of ice. VOC – Volatile Organic Compounds. Compounds that evaporate at room temperature containing carcinogenic elements of carbon C. If you have any questions about HVAC terms that you don’t see on this list, click here to get in touch with us and we can answer your questions.


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