• grue@lemmy.world
    link
    fedilink
    English
    arrow-up
    2
    ·
    7 months ago

    Is that because they were already efficient or because they can’t reasonably be made more sense efficient?

    • Cort@lemmy.world
      link
      fedilink
      arrow-up
      3
      ·
      7 months ago

      I would assume both. They transfer basically all the heat generated into the water and only heat when water is being used.