When contractors talk about air conditioner capacity, they usually measure a system’s cooling performance in tons. There’s a good reason for this and it stretches back to the turn of the century, when keeping homes and foodstuffs cool was done quite differently.
During the late 19th and early 20th centuries, most cooling and refrigeration was done with blocks of ice. Just like modern-day refrigerant, the ice removed heat from a space by absorbing it. As the block of ice reached temperatures of 32 degrees, it did what you’d expect ice to do – melt.
As it turns out, it takes about 143 British Thermal Units (BTUs) of heat per pound to melt a one-ton block of ice. You can take as long as you want to melt a one-ton block of ice, but if you want it done in just 24 hours, you’ll need about 12,000 BTUs per hour to melt the entire block.
If a modern air conditioner can produce the equivalent cooling capacity of a one-ton block of ice absorbing 12,000 BTUs of heat per hour, it’s commonly referred to as a “one-ton” unit. Likewise, four tons of air conditioner capacity is equal to approximately 48,000 BTUs per hour.
Nevertheless, the listed capacity of an air conditioner doesn’t always add up to its actual capabilities. There’s plenty of good reasons for this:
- An air conditioner’s real-world performance is often different than its performance under controlled testing.
- Maintenance and upkeep has a big effect on overall capacity.
- Improper installation can easily reduce air conditioner efficiency and capacity.
With a proper load calculation and system sizing with Manuals J and S, you’ll have the perfect air conditioner that optimally meets your home’s climate-control needs efficiently and effectively.
Powers Heating & Air is dedicated to providing professional cooling and heating service to residential and commercial customers in the Peachtree City area, a proud tradition since 2001. Contact us today to learn more about air conditioner capacity and how it relates to your home-comfort needs.
Our goal is to help educate our customers in Peachtree City, Georgia and surrounding areas about energy and home comfort issues (specific to HVAC systems).
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