There has been an interesting and necessary evolution of water heaters in this country. At we came into the Twentieth Century water was heated on a stove and then hand carried in buckets and bowls to where it was going to be used. The bath water was often kept in the tub until the last family member had bathed. Warm water was added but the dirty water was retained so that the tub would only have to be emptied once. Because of the work involved baths were infrequent and a family might only bath once a week. The stove heated the home and these were the early Space Heating Water Heaters and hot water was only produced on demand.
This early method left a lot to be desired in the realm of instant water heaters. The next step was to develop a unit that could heat the water and store it in a tank until it was needed. They were inefficient as the water had to be heated and then reheated so that it would be available. They were either an electric or gas water heater depending on the fuel source that was available and the cheapest to operate. The tanks needed to be large and the size was dependant on the number of people needing hot water. Space Heating Water Heaters were still a thing of the future and needed more technology. In the last half of the 20th Century solar water heaters started to gain favor. They were very effective in warm sunny environments but needed auxiliary help in cloudy cold areas.
Today we now have gone full circle. The stove which was used to heat the home and the water for bathing has once again been combined with the water heater. Space Heating Water Heaters are now in production that use the same energy to heat water and air at the same time. Coils are now included in the water tanks and air is forced through the heating water. When heat is needed in the home the blower comes on forcing the heated air out of the tank and through the duct work into the home. All the while that the air is being heated there is a constant source of hot water for the occupants to use for bathing or other washing functions.
Space Heating Water Heaters tend to be more energy efficient and have a smaller carbon foot print. Only one heat source is needed to heat both the water and the air. Less fuel is burned and in turn fewer noxious gasses are generated and released into the home
