# What is difference between BTU and MBH for house furnaces?

When selecting a new house furnace most calculators display results as BTUs (based on the square footage, number of levels, estimated temperature, etc). What's interesting is that most new furnaces are spec'ed at MBH.

What is the difference or correlation?

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1 MBH = 1000 BTU/hr. Thousand BTUs per Hour (MBH). – Tester101 Jan 5 '12 at 20:41
so if I need a 16,000 BTU furnace should I be looking for a 16 MBH unit? – jdiaz Jan 5 '12 at 20:51
Maybe... BTU is how much heat is produced at one instance, BTU/hr is the amount of heat produced in an hour. MBH is 1000 BTU/hr. However, BTU is sometimes used as an equivalent to BTU/hr, so the conversion might work. Wikipedia has an article that might clear things up. – Tester101 Jan 5 '12 at 21:10
My SI prefix alarm is blaring in my head about the use of M (Mega) to mean 1,000x (K or Kilo). I'll accept only because BTUs aren't metric. But in my heart I know it should be KBH. – shufler Jan 5 '12 at 21:40
@shufler the M is the Roman numeral for 1000, not M for mega. – Tester101 Jan 6 '12 at 1:28

BTU is how much heat is produced at one instant, BTU/hr is the amount of heat produced in an hour. MBH is 1000 BTU/hr. However, BTU is sometimes used as an equivalent to BTU/hr, so the conversion might work. Wikipedia has an article that might clear things up.

1 MBH = 1000 BTU/hr. Thousand BTUs per Hour (MBH).

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MBH is thousands of BTUs per hour. BTU is a unit of measurement for energy. One BTU is equal to the amount of energy used to raise the temperature of one pound of water one degree Fahrenheit.