What Does BTU Stand for in Water Heaters?
- A BTU is the quantity of heat needed to raise one pound of water by one degree Fahrenheit. More BTUs mean more heating power.
- A water heater is ranked by BTU input, but really means BTUs/hr; thus a 33,000 BTU heater can heat 33,000 pounds of water by one degree in an hour; or, 330 pounds by 100 degrees.
- A more common measure for water heaters is the recovery rate, which indicates the amount of gallons of water that can be heated to 100 degrees Fahrenheit in one hour.
- Another common measure of capacity is simply the size. Home improvement retailer Lowe's recommends a 30- to 40-gallon heater for a two-person home, 50- to 80-gallon heater for five people or more.
- BTUs are more commonly used by heating, ventilation and air conditioning (HVAC) professionals in rating equipment. Homeowners will use recovery rate or simply size.