Let's start at the beginning: HVAC stands for Heating, Ventilating and Air
Conditioning and are the initials often used to describe the industry that produces
the equipment that brings comfort to your home.
ENERGY STAR - A dynamic government/industry partnership between the U.S.
Department of Energy, the U.S. Environmental Protection Agency, product
manufacturers, local utilities and retailers. Partners offer businesses and
consumers energy-efficient solutions, making it easy to save money while
protecting the environment for future generations. The ENERGY STAR label is
now on major appliances, office equipment, lighting, home electronics, and
more. EPA has also extended the label to cover new homes and commercial and
industrial buildings. ENERGY STAR has successfully delivered energy and cost
savings across the country, saving businesses, organizations, and consumers
more than $9 billion a year. Through its partnerships with more than 8,000
private and public sector organizations, ENERGY STAR delivers the technical
information and tools that organizations and consumers need to choose
energy-efficient solutions and best management practices. When properly
installed, ENERGY STAR-labeled products can save consumers about a third on
heating and cooling costs, with similar savings of greenhouse gas emissions.
SEER - This is a measurement of the efficiency of cooling products. The U.S.
Government's minimum efficiency level is 10 SEER for split systems and 9.7 for
packaged units. The higher the SEER, the more efficient the cooling product.
SEER stands for Seasonal Energy Efficiency Rating.
HSPF - This is a measurement of a heat pump's heating efficiency. There is no
governmental minimum rating. The higher the HSPF, the more efficient the heat
pump's heating performance. HSPF stands for Heating Seasonal Performance
A Note About Efficiencies: When you're getting ready to replace an older
heating or cooling system, it's very important for you to get a Load Calculation
done by your dealer/contractor. The greater the difference between the
efficiency of your old system to the new system, the more likelihood that the
dealer will recommend a smaller sized unit. This should not cause alarm, as the
dealer, by running a Load Calculation, will be able to accurately size the system
to the load in your home. It can be quite detrimental to equipment if the units are
too large for the load in your home - they can start to "short cycle" (they run
often but for very short periods of time, because they are pumping out too much
heat/cooling and reach the thermostat's setting too quickly), which can shorten
the life of the unit dramatically
A Note About Capacities: Gas furnaces are generally rated by "input" in Btu's
per hour (Btuh). A furnace rated at 100,000 Btuh that is 80% efficient (80%
AFUE) will have an output of 80,000 Btuh. In other words, 80% of the total heat
produced by burning the gas will be in the form of usable heat to warm your
home. The other 20% is exhausted from your house along with the flue
By the same token, a 100,000 Btuh furnace that is 90% efficient only sends
10% of the total heat out the chimney - thus burning less gas to get the same
results and reducing your gas heating costs.
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
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
Ton - You'll often see this as a measurement of the capacity of an air
conditioning system. Don't panic, it doesn't measure weight! Just like gas and
oil furnaces, air conditioners and heat pumps are rated in Btu's. One ton of air
conditioning is 12,000 Btu's per hour. This means that a "one ton" air
conditioning system has the capability of removing 12,000 Btu's of heat per
hour from your home.
A Note About Air Conditioning: You've heard the saying "It's not the heat, it's
the humidity." Air conditioning systems do more that just cool your home - they
remove moisture. The more humid it is outside, the harder an air conditioner
has to work. But does that mean that if you get a bigger unit, it will work better?
NO. An air conditioning system that is too large will neither cool nor dehumidify
properly, and the result will be an uncomfortable, clammy home.
Ambient Temperature - This is the air temperature (usually the outdoor air
temperature) surrounding the equipment.
Indoor/Evaporator Coil - If your furnace is the air handler section of your
split system, then you'll need an indoor coil added to your furnace to complete
the system. The coil transfers heat to give you cool air and also aids in
Heat Pump - A unit that both cools and heats your home. A heat pump system
can be either a split system or a packaged 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.
Packaged System - Packaged 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. Packaged units come in
several combinations of fuel sources - gas heat/electric cooling; heat pump;
electric heat/electric cooling; oil heat/electric cooling.