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A PLAIN-LANGUAGE GUIDE TO THE TERMS USED IN THIS REPORT

Before examining each brand, here is a brief glossary of the technical terms that appear throughout. Understanding these will help you follow the evidence.

BTU (British Thermal Unit): The standard unit for measuring heating or cooling capacity. A higher BTU rating means a more powerful unit.

Watt (W): The unit of electrical power the unit consumes. The relationship between BTU output and watt input determines efficiency.

EER (Energy Efficiency Ratio): An older efficiency metric calculated by dividing BTU output by watt input. No longer the legally required rating in the US or Canada for most product types covered here.

EER2: An updated version of EER using a revised test procedure. Required under current US regulations.

SEER / SEER2 (Seasonal Energy Efficiency Ratio): A measure of cooling efficiency over an entire season. SEER2 is the current legally required standard in the US. The minimum required SEER2 for the product category covered here is 13.4.

HSPF2 (Heating Seasonal Performance Factor 2): The legally required heating efficiency metric in the US.

COP (Coefficient of Performance): A heating efficiency ratio. Not the legally required metric in the US or Canada for the products covered here.

CEER (Combined Energy Efficiency Ratio): A Canadian efficiency metric. It applies only in Canada and only until May 26, 2026. Critically, CEER must always be lower than EER for the same unit, because it accounts for standby power consumption. Any brand claiming a higher CEER than EER is publishing an impossible number.

AHRI Certification: Third-party verification by the Air-Conditioning, Heating, and Refrigeration Institute that a product performs as claimed. None of the products in this report hold this certification.

PTHP (Packaged Terminal Heat Pump): A specific product category defined by law. A PTHP must be designed for through-the-wall installation with a removable chassis and a wall sleeve. Products that do not meet this design definition cannot legally be labelled as PTHPs.

NRCan Searchable Product List: A mandatory Canadian government database where energy-consuming products must be registered before sale. Absence from this list means the product is not legally approved for the Canadian market.

DOE CCMS Database: The US Department of Energy’s Compliance Certification Management System — the equivalent mandatory registration database for the American market.