The abbreviation for the British thermal unit, BTU is a unit of work that is the rough equivalent of 1055 joules and 252 heat or little calories. Used primarily in the United States and sometimes in the United Kingdom, the British thermal unit represents the amount of thermal energy required to increase the temperature of one pound of water by one degree Fahrenheit. The foot-pound-second system, an English system, uses the BTU, while other countries employ the International System of Units, which uses joules. BTU is also known as Btu or B.Th.U.
Every combustible material has a British thermal unit rating. According to our research, a pound of burning wood will generate around 7,000 British thermal units, a gallon of fuel oil will generate 140,000 BTU, while a gallon of liquid propane will produce roughly 92,000 BTU. Larger BTU generators include a barrel of gasoline, which can produce 4.35 million BTU, and a ton of coal, which produces 20 million BTU. Despite its name, the British Thermal Unit is more commonly used in the United States and Canada than in the United Kingdom. In countries that employ the Btu, this unit is also used for measuring natural gas prices, with one cubic foot of natural gas equaling 1,034 Btu units.
To illustrate the practical use of BTUs, consider the following example: if you want to boil one gallon of water that has a starting temperature of 60 degrees Fahrenheit, you will need approximately 1,200 BTU to bring the water to its boiling point of 212 degrees Fahrenheit.
The British thermal unit is also used for quantitative specifications regarding the energy transferring and producing attributes of cooling and heating units, such as ovens, refrigerators, air conditioners, and furnaces. The heat output of computer equipment is usually specified in BTUs to be taken into account when technicians plan the climate control system within a house or building. Expressed in BTU per hour, the output of computer device heat is the equivalent of one watt of heat dissipation.
When discussing heating a building, BTUs describe the heat produced by the fuel or energy source, which can come from various sources such as LP gas, electricity, natural gas, or oil. When talking about cooling a building, the rated capacity for the air conditioning unit or heat pump will be expressed in BTUs, referring to the removal of a given amount of heat from a room.
BTUH, BTU/Hr, or British Thermal Unit per hour refers to the number of BTUs of energy generated (for heating units) or removed (for air conditioning units) in an hour.
Heating, ventilating, or air conditioning units may display two BTU capacities on the appliance label:
MBtu is described as one thousand BTU. Other common abbreviations include mBtu, MMBtu, or mmBtu. The "M" is presumed to stand for the Roman numeral system, where this letter signified one thousand. In this context, MMBtu would be rendered incorrect, as it would stand for two thousand. However, MBtu is also mistaken for the SI "M" prefix that stands for multiplication by one million, while mBtu is mistaken for the SI "m" that denotes division by one thousand. Some companies use "therm" to describe 100,000 BTU, while others use BtuE6 to avoid any confusion between 10,000 BTU and 1,000,000 BTU.
There are plenty of online calculators to help with converting BTU to watts, watts to BTU, BTU to tons, and BTU to kWh. If you want to perform the conversions manually, you can use the following specifications:
| Unit | Conversion |
|---|---|
| 1 watt | 3.4121 BTU per hour |
| 1 BTU per hour | 0.29307 watts |
All gas grills available on the market will have a maximum British thermal unit per hour rating. A gas grill that advertises 35,000 Btu translates to a device that produces that amount of Btu with all its burners in an hour. The gas grill in this example will use approximately two pounds of propane in an hour. However, the BTU rating advertised by a gas grill should not be the sole factor in determining its heat output. The rough estimation regards its heat output and only lets you know how much fuel it will consume.
To determine the efficiency and power of a gas grill, you should also factor in the design, materials, and size of the gas grill. If the grill is lightweight and its overall efficiency is not satisfactory, it will need a higher BTU output to cook food in a reasonable amount of time. However, infrared grills won't require a large number of BTUs per square inch due to their impressive build and the conversion of heat from the burners into radiant energy, making them more efficient. Gas grills that boast unrealistic BTUs per square inch are probably hiding a flimsy build.
To choose the right heating or cooling systems for a house or building, you first have to figure out the required BTU per square foot. This involves calculating the space that needs to be cooled or heated, which will help you in your hunt for the perfect air conditioning or furnace. You can use a BTU calculator or follow the DIY method explained below.
The majority of air conditioning units on the market express their capacity in BTU. When discussing heating, a ton is the equivalent of 12,000 BTU. The rough estimates that people usually take as a guideline are 30 BTU per square foot. For example, a 2,000 square foot house will need a 5-ton air conditioning unit, which translates to 60,000 BTU.
Another factor to consider is the Energy Efficiency Rating (EER), which is calculated by dividing the BTU of an air conditioning unit by its wattage. For example, to calculate the EER of a 10,000 BTU air conditioning unit that needs 1,200 watts, divide 10,000 by 1,200, which gives an EER of 8.3. Knowing this number and estimating how much you will use your air conditioning unit during the summer, you can determine if an AC unit is worth the investment.