BTU is the unit of measurement that indicates how much energy your air conditioner will use to heat up or cool down a specific area, in a one-hour period.
It’s important to make the right choice – a higher number of BTUs isn’t always the answer as it can shorten the unit’s lifespan by not allowing it to function optimally for the space.
Top floor apartments and second stories are often warmer than the ground floor because warm air rises, and, because it’s likely to get more sun exposure. This means that you’d typically need an air conditioner with a higher number of BTUs.