it runs out, your water heater is put to work instead.
it’s good that you’re thinking about changes to make to your home to make it more energy efficient. but how about the build itself? if you’re in charge of how the build is being done, there are a lot of steps you can make to make the whole process a lot more earth friendly. recycling your content is one way. planning the construction site itself matters, too. if you can reduce as much energy movement and reduce the time it takes to travel from one task to another, you have a much more efficient site.
to top off the house, you’re 