What Do the Different Energy Ratings for Heating and Cooling Systems Mean?

Energy ratings may seem complex, but they are often just trying to measure different ratios of the same general figures.  along with how they relate to your energy consumption:

BTUs — British Thermal Units

Energy use is measured by this standard unit. The higher the BTUs, the more heat is generated. You can determine the energy required to heat or cool your home by using handy BTU calculators located online.

To choose the most efficient HVAC services, you must look to the device’s BTU rating and also how your fuel costs compare to their relative BTU generation. For instance, propane generates 91,500 BTUs per gallon and electricity generates 3,413 BTUs per kilowatt hour. You can then figure out how much money per BTU you are paying for utility service, and how that translates to the device or system in question.

SEER — Seasonal Energy Efficiency Ratio

Used to measure cooling power compared to energy usage, this figure determines the average number of BTUs you earn per watt of electricity used over a typical cooling season. Higher numbers mean higher efficiency (and better savings). High-efficiency cooling systems have SEER ratings of 14.5 and above.

EER — Energy Efficiency Ratio

Similar to SEER, EER measures BTUs created compared to the kilowatt hours of electricity used over one hour of average temperatures. While SEER provides an average, EER looks at energy used during peak performance. This measurement is used mostly for window air conditioning units.

AFUE — Annual Fuel Utilization Efficiency

This figure is obtained by first looking at the efficiency rating of the furnace or heater, expressed by how many BTUs it can generate compared to the fuel it uses. The general efficiency rating is divided by the fuel usage by the device over a typical year to obtain the AFUE. High-efficiency fuel-based heating systems have AFUE ratings of 90% and above.

HSPF — Heating Season Performance Factor

HPSF is like SEER, but for heat pumps. The number is obtained by taking the BTUs of heating required over the cold season and dividing it by the total kilowatt hours of electrical energy needed to provide this level of heating. High-efficiency heat pumps have HSPF ratings of 8 and above.

COP — Coefficient of Performance

COP measures the heat provided compared to the energy used to create it. The higher the number, the more efficient the system is.

R Value

While not a direct component of HVAC system installation, R values refer to the insulation of the home that will be needing heating or cooling. Proper insulation can reduce HVAC usage over a season by reducing the amount of heat transfer from the interior of the home to the outdoors.

This number is expressed as a ratio of the difference in temperature between the indoors and outdoors compared to how much energy is transferred between the spaces. Higher R values mean more heat is retained in the home during all seasons. Because of this fact, the recommended R value for your home will be different based on the climate you live in.

U values are the opposite ratio, and they measure heat emissivity (transfer) of windows. U values below 0.3 are needed to earn an Energy Star rating.

Anyone who wants to make smart decisions about buying a new HVAC system or addressing their home’s insulation should consult these figures to ensure the optimal level of heating and cooling efficiency.

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