Answer 1 BTU for 1°F Change in 1 lb of Water

[supak111]

I know that 1 BTU is energy needed to raise 1lb of water 1 fahrenheit.

Does that also mean that if I were to lower the temp of 1lb of water by 1 fahrenheit that I have used 1 BTU of energy?

Does it apply both ways?

 

[billy_joule]

To raise the temperature of something you need to add energy, to lower the temp you need to remove energy.
So to lower the temp of 1lb of water by 1 Fahrenheit you need to remove 1 BTU of energy from the water.