Sources:
https://www.energystar.gov/products/energy_star_home_tips
http://energy.gov/energysaver/reduce-hot-water-use-energy-savings
https://www.energystar.gov/products/heating_cooling/programmable_thermostats/proper_use_guidelines
http://energy.gov/energysaver/tankless-or-demand-type-water-heaters
http://energy.gov/energysaver/articles/15-ways-save-your-water-heating-bill
https://www.energystar.gov/products/energy_star_home_tips
http://energy.gov/energysaver/reduce-hot-water-use-energy-savings
https://www.energystar.gov/products/heating_cooling/programmable_thermostats/proper_use_guidelines
http://energy.gov/energysaver/tankless-or-demand-type-water-heaters
http://energy.gov/energysaver/articles/15-ways-save-your-water-heating-bill