System Replacement

Is it time to replace your heating or cooling system?

Air Conditioning Installation in Maryland by BESTHow do I know when it is time to replace my heating or cooling system?  If your present system is over 20 years old, you may want to start planning to replace it soon. Over the years, we have seen systems last 25 – 30 years but that is rare.  As the price of energy continues to climb, it makes “cents” to replace your system with a more efficient one.  Systems that were installed 20 years ago were in the range of 6 SEER and now the least energy efficient system is 13 seer and most new ones going in are in the 15 – 20 seer range.

How do I as a homeowner know all the jargon that an HVAC contractor uses when they are designing a system for me? Allow us at Thompson BEST to give you a brief definition of all the terms that are most important to you.


In short, SEER ratings are for air conditioners, HSPF is for heat pumps, and AFUE is for oil and gas furnaces. Listed below are more detailed explanations for each.

SEER rating means “seasonal energy efficiency ratio” It’s a benchmark of how much electricity a given A/C system uses to deliver each Btu/h of cooling power compared to another one under a standard, fixed set of rating conditions. This benchmark system is managed by the Department of Energy, and they decide what the testing standards are. The higher the SEER number is, the higher the score the system has received on the D.O.E. mandated efficiency tests.

Many homeowners don’t understand that the emphasis here is on the word “system”. And the outside unit is only one part of the cooling system. You also have the inside cooling coils (sometimes called the evaporator or A-coil). The blower system in the furnace (or air handler) is also a part of the system as far as the SEER testing goes, because the SEER rating is based on the amount of cooling produced by the outside unit and the cooling coils – using the air volume delivered by the blower system. The blower motor in the furnace or air handler uses x amount of electricity, as does the outside unit. And the SEER rating tests are basically calculating how much total electricity the system uses to deliver its BTU of cooling. So the SEER tests are conducted with a furnace (or air handler), an outside unit, and a inside cooling coil. In other words, there is technically no such thing as a “13 SEER” outside unit when you come right down to it. The same outside unit could end up with a higher or lower than 13 SEER score, depending on the inside coil and furnace (or air handler) being used to test it with.

To make a long story short, the SEER rating is a combination of typically 3 components (air handler, coil, and outdoor unit.)  Make sure that your HVAC contractor shows you the ARI rating comparing all 3 components to get the highest rating for you.

HSPF is an acronym that stands for “Heating Seasonal Performance Factor”. HSPF is a rating like SEER but instead of being a rating used to measure the efficiency of a cooling system; it is a rating to measure specifically the heating efficiency of a heat pump. A heat pump has both a SEER and an HSPF rating since it can both cool and heat a building. The higher the HSPF number, the higher the energy efficiency. The HSPF rating is calculated by the total heating required during the heating season (in BTU) divided by the total electric energy consumed by the heat pump system during the same season (in watt-hours).

AFUE (AFUE; pronounced ‘A’-‘Few’) rating means the “annual fuel utilization efficiency” is a thermal efficiency measure of combustion. It is when you need to measure the thermal efficiency of your furnace or water heater, AFUE (Annual Fuel Utilization Efficiency) helps to determine the actual, season-long, average efficiency of that piece of heating equipment. It measures the amount of heat actually delivered to your house compared to the amount of fuel that you must supply to the furnace. The U.S. Department of Energy determined that all furnaces sold in the U.S. must have a minimum AFUE of 78%.

If you are replacing a gas furnace, Thompson BEST now has York propane or natural gas furnaces that modulate the heat from a low flame to a high flame when the outside temperature drops into the teens. This furnace has a 97.5 AFUE rating. An important note is that the gas piping is tested for any leaks with a leak detector.

When replacing an air conditioner or heat pump, make sure that the installer reclaims the refrigerant with an approved machine.  The installer should also replace the condensate pump, pad, and use snow legs, duct tie-in custom fabricated for your installation, copper wiring, and new refrigeration tubing. If they do not install new refrigeration tubing, make sure they clean the tubing with a “flush Kit” before changing from R-22 to R-410.  At Thompson BEST, we re-cycle all refrigerant, scrap metal, and cardboard saving this waste from going into our landfills or air.


Aprilaire – learn more here

Lennox – learn more

Lennox financing

York  – learn more here

Gas Logs & Accessories – learn more here


Email Charlie for more information, or call Md. 301-662-0600 or Va 703-443-2378.

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