The world of heating and cooling certainly has its fair share of tricky technical language, which can make it difficult for consumers to make an informed decision when buying new equipment. Efficiency ratings in particular can be a little confusing, so we decided to publish this brief explanation on HSPF, SEER, and AFUE aimed to answer the basic questions: what they are, what they mean, and what to look for as a buyer.
AFUE
We’ll start with AFUE because its the simplest and most applicable since it applies to a large variety of equipment. The acronym stands for Annual Fuel Utilization Efficiency, and it is used primarily to describe the efficiency of combustion heating equipment such as Gas/Oil furnaces, Fireplaces, and Boilers; although it also applies to equipment that uses an electric element for heating. AFUE is a percentage, with 100 being the natural maximum (although technically impossible to achieve via the 1st law of thermodynamics). At the low end of the scale are gas fireplaces, which generally run around 60-70 AFUE (depending on the fuel and particular fireplace model). Gas and Oil Furnaces have greatly increased in efficiency over the last few decades. If your furnace is over twenty years old, its probably 70-80 AFUE. Newer gas/oil furnaces range from 80-98 AFUE. Boilers are typically 80-98% AFUE. Electric furnaces and other electric heaters are almost always 99 AFUE, however this can be a misleading in terms of operating cost, because a 99 AFUE Electric furnace can cost 3 times as much to operate as a 95 AFUE gas furnace. Remember to factor in fuel cost when looking at a system’s efficiency to determine operating cost.
SEER
SEER, or Seasonal Energy Efficiency Ratio applies primarily to air conditioning units, although many heat pump manufacturers also list a SEER rating for their equipment. SEER applies only to cooling, so when looking at Heat Pumps and Ductless Units, its important to look at HSPF for the heating efficiency (or AFUE if the system uses combustion heat). SEER is basically the total cooling output divided by the amount of electricity used during a given season (usually calculated as the period air conditioning is used the most e.g. late spring, summer, early fall). A related efficiency scale called EER gives the Energy Efficiency Ratio for a whole year, but SEER is generally more accurate since most people don’t run their air conditioning in December. As of 2006, new air conditioning units must be at least 13 SEER; Energy Star certification is 14 SEER and up. Marr’s recommends at least 15 SEER for A/C, or higher depending on how often the equipment will be used. We sell equipment up to 21 SEER, and although the upfront cost is slightly higher for more efficient equipment, the lower operating cost can make a huge difference on monthly utility bills.
HSPF
HSPF stands for Heating Seasonal Performance Factor and is primarily used to measure the heating efficiency of heat pumps and ductless heat pumps, although it is also used (somewhat confusingly) to describe the overall heating and cooling capabilities of a system. HSPF is the amount of heat generated divided by the amount of electricity used, calculated as an average over the heating season. Essentially, its the opposite of SEER, so both ratings are needed to evaluate the overall efficiency of any compressed refrigerant system that offers both heating and cooling. As a reference point, an HSPF of about 3 means that the unit is producing heat equal to the electrical energy its using. Unlike combustion heating systems though, heat pumps can go far beyond 100% efficiency. Our Daikin ductless heat pumps systems get up to 9.5 HSPF, producing 3 times the amount of heat per watt of electricity used. Carrier Infinity forced air heat pumps get up to 13 HSPF. This level of efficiency is a very recent development and is the result of decades of research; Marr’s Heating and Conditioning is proud to offer these advances from a variety of manufacturers and models.
Looking for a high-efficiency solution to your heating or cooling needs? Give us a call today and our owner will personally come meet with you to find the perfect solution for your home.
Marr’s Heating and Air Conditioning
1677 Mt. Baker Hwy.
Bellingham, WA 98226
