You'll save 454 kilograms of carbon dioxide/year by wrapping your water heater in an insulating blanket, and another 250 kilograms by setting the thermostat under 49 degrees Celsius.
The AQHI is an initiative of Environment Canada, Health Canada, the B.C. Ministry of Environment, the B.C. Ministry of Healthy Living and Sport, the B.C. Ministry of Health Services, Metro Vancouver and the B.C. Lung Association.