# 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?

• 1 MBH = 1000 BTU/hr. Thousand BTUs per Hour (MBH). Jan 5, 2012 at 20:41
• so if I need a 16,000 BTU furnace should I be looking for a 16 MBH unit? Jan 5, 2012 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. Jan 5, 2012 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. Jan 5, 2012 at 21:40
• @shufler the M is the Roman numeral for 1000, not M for mega. Jan 6, 2012 at 1:28