DIYbanter - View Single Post - Quick basic advice on a dripping gas 40-gal hot-water heater

Rick Blaine

(Malcolm Hoar) wrote:

If both a 50 gallon and 40 gallon water heater has the same 59 percent
efficiency factor ... do they cost the SAME to heat?

Nope.

Yes they do. Basic physics says that it takes the same amount of energy to heat
the same water, regardless of the container size.

Or does the 50 gallon water heater actually cost more even if it's the same
efficiency?

Yup.

But not because it takes more energy to heat the water, because the heat loss
from the tank is slightly higher.