BTU to tons calculator

Not exactly — the nominal size is a label, and the certified capacity of the particular indoor and outdoor combination is published separately and is usually a little under it. The three digits in a residential model number are the nominal capacity in MBH, so 036 means the machine is sold as 36,000 BTU/h, while the AHRI listing for that exact coil pairing might read 34,600 at the rating conditions. Sizing decisions are made against the certified figure; the nominal one exists so that a wholesaler can stock a product line.

Because the definition uses a rounded latent heat of fusion. Ice actually absorbs about 143.4 BTU per pound as it melts, which would make a short ton in twenty-four hours 11,950 BTU/h; the unit was fixed at 144 BTU/lb instead, and 2,000 × 144 ÷ 24 is exactly 12,000. Rounding the input rather than the answer is what lets the ton be an exact conversion in both directions forever.

It is a rate: 8,000 BTU per hour. Nobody writes the hour because the industry has been dropping it for a century, and the confusion it creates is the reason this converter refuses a figure typed with an energy unit on it rather than guessing. There is a second wrinkle specific to portables sold in the United States: the DOE test procedure at 10 CFR 430 Subpart B, Appendix CC rates them on a seasonally adjusted basis that accounts for the duct and the infiltration it pulls in, and that number is lower than the older rating for the same machine, so two boxes on the same shelf may not be quoting the same test.

A thousand. The M is the Roman numeral for a thousand and not the SI mega- prefix, so an 80 MBH furnace puts out 80,000 BTU/h and a 2,000 MBH boiler is two million. The unit that genuinely means a million is MMBTU — one thousand thousand, the Roman numeral doubled — which the gas industry uses for fuel purchases and which is a quantity of energy rather than a rate.

It is the metric-market equivalent of BTU/h and it appears on cooling equipment sold outside North America, particularly in southern Europe, Latin America and parts of Asia. One kilocalorie is 4,186.8 joules by the International Table definition, so one kcal/h is 3.968 BTU/h and one ton comes out at about 3,024 kcal/h. Spanish-language listings often quote the same figure as frigorías, which is a kilocalorie of cooling rather than heating and converts identically.

No — those are two different quantities and the conversion on this page is not the one you want. The kW figure here is the heat the machine moves, expressed in metric units; the kW it pulls off the panel is that divided by its efficiency. The bridge between them is the COP, which is the EER divided by 3.412142, so a machine moving 36,000 BTU/h at an EER2 of 12 is drawing roughly 3 kW, not the 10.55 kW its capacity converts to.

Historically yes, dimensionally no. The unit is a survival from the ice trade: a mechanical plant was sold by how many tons of ice a day it could replace, so the rate of cooling that melts one short ton in twenty-four hours became the unit and kept the name. A ton of refrigeration is a rate of heat flow, a short ton is a mass, and the tons a press brake is rated in are a force — three unrelated quantities sharing one word, which is why a converter has to know which of them you are holding before it can be any use.