Comments by "Scott Franco" (@scottfranco1962) on "A simple water heater is more clever than it seems" video.

  1. Electric water heaters are the least efficient, followed by gas water heaters, then on demand heaters. Good luck finding an electric on demand heater of any size. The vast majority of them are small under sink units. The most efficient are heat pump water heaters, but then you are back to storing the energy in a big tank. The least cost heaters are solar, but not that much better, because you have to pay to operate the circulation pump. The energy storage capability of a tank of water is impressive. I worked in a building that had air conditioning from this principle in The San Fernando valley outside of LA. It gets over 100 degrees F every day all summer. The air conditioning worked by storing water in the basement, and sending it to a roof array every night to radiate off the heat in the water to the sky. Then the water was used to cool the building by day.
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