Btu per Hour to Watts Converter

Understanding the Btu/h to Watts Conversion

BTU per hour is the standard power rating for heating and cooling equipment in the United States, while watts dominate international specifications and electrical engineering. When you need to compare a US-rated furnace against a metric-rated heat pump, or figure out how much electrical capacity an HVAC system demands, converting between these units is unavoidable.

A common mistake is confusing BTU (energy) with BTU per hour (power). Equipment spec sheets nearly always mean Btu/h when they say “BTU” in a capacity context, but mixing them up leads to calculations that are off by a factor of 3,600. Another frequent error is using rounded conversion factors that accumulate meaningful error at scale, particularly when sizing commercial systems rated in hundreds of thousands of Btu/h.

How to Convert Btu per Hour to Watts (step by step)

Step One: Understand the conversion constant

One BTU per hour is defined as exactly 0.293071 watts. This value is derived from first principles using the energy content of a BTU and the number of seconds in an hour.

1 Btu/h = 1055.06 J ÷ 3600 s = 0.293071 W

1 Btu/h = 0.293071 W

Step Two: Multiply by the conversion factor

Take your Btu/h value and multiply it by 0.293071 to obtain watts.

watts = btu_per_hour × 0.293071

Using the default value of 5 Btu/h:

watts = 5 × 0.293071 = 1.465355 W

A device producing 5 Btu/h of thermal output is equivalent to roughly 1.47 watts of power.

What Your Results Mean

The watt value represents the same rate of energy transfer, just expressed in SI units. This makes it directly comparable to electrical ratings on breakers, generators, and utility bills. For quick mental math, remember that 1 ton of cooling (12,000 Btu/h) is about 3.5 kW, and a typical home furnace at 80,000 Btu/h draws roughly 23.4 kW equivalent.

Btu per Hour to Watts Conversion Table