Spiderman vs. Batman
Who would win in a fight, Spiderman or Batman? Sure, Spiderman has heightened senses, climbs walls, and lifts six times his weight, but Batman is an accomplished martial artist, has gadgets galore, and finds time to run a Fortune 500 company on the side. The fact of the matter is, this isn’t a fair comparison. One has superpowers and one is just a regular guy[1]. They aren’t even from the same comic universe[2]. When comparing two pieces of energy-using equipment, the arguments can be just as unfair.
Making a Comparison
Say a new air conditioner needs to be purchased and bids are requested from two different manufacturers. Manufacturer A’s equipment has an energy efficiency ratio (EER)[3] of 12.0 EER and costs $20,000. Manufacturer B counters that his equipment has an efficiency of 12.5 EER and costs $17,000. Seems pretty cut and dry, right? Not so fast. Much like Spiderman vs Batman: this may not be a fair comparison.
The efficiency of air conditioning units depends greatly on the conditions at which the unit is operating. If a unit is supplying 55 degree air at an outdoor air temperature of 90 degrees, it will use far less energy than a unit supplying 45 degree air at an outdoor air temperature of 100 degrees. If the operating conditions of two different pieces of equipment are unknown, it is impossible to compare them effectively.
Fair Fight
Thankfully, there are standards and resources that ensure equipment is tested at identical conditions so they can be accurately compared. For HVAC equipment, the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has standard testing procedures for a wide variety of equipment. They even have an online directory for easy access to this information. The same is true for the Compressed Air and Gas Institute (CAGI) for compressed air systems, ENERGY STAR for appliances and a variety of other equipment, and the Design Lights Consortium (DLC) for lighting. All of these resources ensure that equipment is tested at identical conditions so it can be fairly and appropriately compared. Additionally, when equipment is included in these databases, it has the added benefit of indicating that it comes from reputable companies that have the time and resources to make sure their equipment is properly certified.
Don’t spend time fighting over Batman and Spiderman. Instead, compare A against B over the entire typical cooling seasonal conditions. Having equipment rated at standard conditions is like comparing the Star Wars and Star Trek[4] franchises, or which Fast and Furious movie is the best[5] – things that just make sense.
[1] Relatively speaking
[2] Spiderman = Marvel, Batman = DC. Stay with me here.
[3] An Energy Efficiency Ratio (EER) is the ratio of the cooling capacity of an air conditioner in British Thermal Units (BTU) per hour, to the total electrical input (in watts) under certain specified tests. It is commonly used as a measure of cooling efficiency.
[4] Star Wars
[5] Fast Five
