A BTU is a traditional unit of heat defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. In the HVAC world, it measures the cooling or heating capacity of a system to ensure it is sized correctly for your square footage. For smaller rooms or home offices, a 9000 BTU system is often the perfect, energy-efficient choice. If you are cooling a standard living room or master suite, you may want to step up to an 18000 BTU model to ensure comfort during extreme heat. We categorize our entire inventory by these ratings, including our high-capacity 60000 BTU systems for large-scale applications. Understanding BTUs is the first step toward choosing the right system from our single-zone floor console or wall-mounted collections.