HVAC Terms and Definitions

Hi, this is Chris from John C. Flood and today we're going to go over some common questions and terms used within the HVAC world. Hopefully, after you listen to this podcast you'll have a better basic understanding of what these terms mean. First on the plate is what size air conditioner do I need for my home. Sizing a residential heating, ventilation and air conditioning otherwise known as HVAC unit, depends on such variables as square footage of your home, geographic location, orientation to the sun, construction details, insulation values, window area and type, et cetera. Under sizing a system may lead to warmer or cooler temperatures than desired by some occupants. Over-sizing the system may lead to humidity or moisture control problems in the space.

What is a BTU? A BTU stands for the British Thermal Unit. It's a unit of heat energy within the inch-pound unit system which is common today in the United States. The BTU is defined as the amount of heat necessary to raise the temperature of one pound of water one degree Fahrenheit from 58.5 to 59.5. A BTU is commonly used to indicate the heating and cooling capacity of a system, heat losses and heat gains. To give an example of a system capacity, a 10,000 BTU window air conditioner is capable of removing 10,000 BTUs of heat per hour. And to give an example in terms of heat gains, the typical heat gained added to a room by an adult person at rest is about 200 BTUs per hour. Now, what is a ton? A ton is the unit of measurement for air conditioning system capacity. One ton of air conditioning removes 12,000 BTUs of heat energy per hour from a home. Central air conditioners are sized in tons and residential units usually range from one to five tons.

What does EER mean? And should I spend more money for higher EER unit? EER stands for Energy Efficiency Ratio. The higher the EER rating, the more energy efficient the equipment is. This can result in lower energy costs. If we go to the US Department of Energy's website you can calculate the potential energy cross-savings of a more efficient unit. And the Air-conditioning and Refrigeration Institute, which is ari.org, post a certified ratings directory which lists EER ratings of various air conditioning equipment.

What does SEER mean and should I spend more money for higher SEER unit, which is S-E-E-R? SEER stands for Seasonal Energy Efficiency Ratio. The higher the SEER rating, the more energy efficient the equipment is. A higher SEER unit can result in lower energy costs and again, if you visit the US Department of Energy's website, they have a tool which will allow you to calculate the potential energy cross-savings of a more efficient unit. And also, once more, the Air-Conditioning Refrigeration Institute which again is ari.org, post a certified ratings directory which lists SEER ratings of most commonly used various air conditioning equipment.

Next, what does HSPF mean? HSPF stands for Heating System Performance Factor. The higher the HSPF rating the more energy efficient the equipment is. A higher HSPF can result in lower energy cost. The Air-conditioning and Refrigeration Institute post a certified ratings directory which lists HSPF ratings of various air-conditioning equipment. And lastly, what does AFUE mean? AFUE stands for Annual Fuel Utilization Efficiency. The higher the AFUE rating the more energy efficient the equipment is. A higher AFUE can result in lower energy cost.

The Gas Appliance Manufacturers Association, which can be found at www.gamanet.org, publishes a directory of certified AFUE ratings. And as always, thanks for listening and, as always, if you have any question please visit www.johncflood.com where we're always adding educational videos, documentation and podcast to help you answer any questions you may have. And if you need additional information please don't hesitate to contact us. Thanks.