Water heating is a major energy cost for everyone. Typical energy usage is 250 therms of natural gas or 3500 kilowatt hours, totalling $200 to $500 annually for a family of three to four people. The best typical gas-storage water heaters are only 64% efficient. Water is becoming an increasingly scarce resource and homeowners are wise to increase the efficiency of their water use. Outdoor watering is typically the most consumptive water use and so shade and outdoor water efficiency are the most important water-saving measures. Indoors, toilets and low-flow showerheads are effective water savers.