Technicians use a "blower-door test" to accurately measure air leakage in houses. The test involves sealing a portable, frame-mounted fan in an exterior doorway to the house. Any known openings to the outside, such as the fireplace flue; bathroom vent fans; and the flues to the water hea...
Or, given the same geographical and climatic situation, if two people in the house want to use hot water at the same time, those two users might have to share the hot water coming out of the water heater -- and neither is likely to be satisfied with how much they are getting. The k...