To solve this we are going to use a conversion factor. We know that 1 BTU per hour is approximately 778 foot-pounds of energy per hour, so our conversion factor will be: 
.
Now we just need to multiply <span>4000 BTU by our conversion factor:
</span>
<span>
We can conclude that the furnace released </span><span>3,112,000 foot pounds of energy in one hour.</span>
Now we just need to multiply <span>4000 BTU by our conversion factor:
</span>
<span>
We can conclude that the furnace released </span><span>3,112,000 foot pounds of energy in one hour.</span>