What is watt?

The watt is the SI base unit of power. It is universally used to measure the rate of energy consumption or production in electrical appliances, engines, lighting, and virtually all power-related specifications.

Real-world uses

The watt is the SI unit of power, used to rate electrical appliances (a kettle is about 2,000 W, an LED bulb 8–12 W), solar panels, audio amplifiers, and motors. Electricity generation at power stations and renewable installations is measured in watts and its multiples.

History

Named after Scottish engineer James Watt (1736–1819), the unit was adopted by the Second Congress of the British Association for the Advancement of Science in 1882. Watt's improvements to the steam engine were foundational to the Industrial Revolution.

Common mistakes

Confusing watts (power) with watt-hours (energy). A 100 W light bulb uses 100 watt-hours of energy per hour. Also, equating wattage with brightness for LED bulbs—lumens measure brightness, watts measure power consumption.

What is ton of refrigeration?

A ton of refrigeration is a power unit measuring the heat removal capacity of cooling systems, equal to 12,000 BTU per hour. It is the standard capacity rating for commercial and industrial air conditioning units in the United States.

Real-world uses

The ton of refrigeration (TR) is used for rating commercial and industrial cooling systems, chillers, and large-scale HVAC equipment. A small commercial building might need a 20–100 TR chiller. Data centres measure cooling capacity in TR. One TR = 12,000 BTU/h = approximately 3.517 kW.

History

The ton of refrigeration originated in the 19th century ice trade, when mechanical refrigeration systems were judged by their ability to replace ice delivery. One ton was defined as the cooling equivalent of melting one ton of ice per day. As mechanical refrigeration displaced natural ice by the early 20th century, TR became a standard industrial cooling unit.

Common mistakes

Confusing refrigeration tons with metric tons of mass—they are completely unrelated. Also, the "ton" in TR originated from the cooling power needed to melt one short ton (2,000 lb) of ice in 24 hours, not from any mass being cooled.

When is this conversion used?

Converting between watt and ton of refrigeration is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.

Worked examples

1 watt = 0.00028435 ton of refrigeration

1 ton of refrigeration = 3,516.85284 watt

How to convert watt to ton of refrigeration

To convert watt to ton of refrigeration, multiply the value by 0.00028435.

To convert ton of refrigeration back to watt, multiply by 3,516.85284.

Measurement standards

The watt is the SI derived unit of power, defined as one joule per second (kg·m²/s³). Horsepower remains in widespread informal use, particularly in the automotive industry, but has no single universal definition across regions.

Did you know?

The human body at rest produces about 80 watts of power — roughly enough to keep an incandescent light bulb glowing. During intense exercise, a trained cyclist can sustain over 400 watts, and elite sprinters briefly exceed 2,000 watts.

Quick reference: watt to ton of refrigeration

Common values

Available Power units

• watt conversions
• kilowatt conversions
• horsepower (mechanical) conversions
• megawatt conversions
• gigawatt conversions
• milliwatt conversions
• microwatt conversions
• BTU per hour conversions
• kilocalorie per hour conversions
• ton of refrigeration conversions

More watt conversions

• Convert watt to kilowatt
• Convert watt to horsepower (mechanical)
• Convert watt to megawatt
• Convert watt to gigawatt
• Convert watt to milliwatt
• Convert watt to microwatt
• Convert watt to BTU per hour
• Convert watt to kilocalorie per hour
• Convert watt to ton of refrigeration

Assumption: horsepower values use mechanical horsepower.