DIYbanter - View Single Post - 40 gal just not enough: Replacing water heater for 2400 sq home. Family of 2 adults + 2 children

Wayne Whitney

On 2008-04-08, wrote:

plus you always talk of 20% going up the chimney as standby loss but
refuse to supply a link to verify that

I don't understand this criticism, we've been over this before. The
energy factor of typical gas tankless is 0.80 and the energy factor of
a typical gas tank is 0.60. The difference, 20% of the theoretical
heat value of the gas used, is the standby losses. Most of the
standby losses go up the central flue of a conventional gas tank water
heater, as there can't be any insulation between the flue and the hot
water.

Yours, Wayne