A single tank solar water heating system combines solar preheated water and backup heating into one tack, which is in contrast to a typical two tank systems which will separate these functions. In either case solar water heating systems can save 55% to 85% on your water heating costs. Since water heating is the second largest energy guzzler in your home this can mean some serious savings in the future. Most single tank solar water heaters feature a 240 watt electric heating element in the top half of the tank. This element heats the water in the upper half of the tank while the water in the lower half is heated by the solar collectors. If the environmental impact of you energy choices is important to a single tank system can offer impressive savings. Here is a brief description of shrinking your green house gas emissions when it comes to heating your water. Of water heating appliances tank system water heaters fueled with natural gas can create some of the greatest carbon dioxide emissions - actually at ton or more of CO2 per year. Replacing a gas fired tank style heater with a tankless gas water heater can cut the emissions by about 15%. Combing a solar preheating system with a tankless backup is a much bigger step in reducing your enviro footprint, somewhere in the range of 60% greater in terms of energy and environmental savings. Because source of electricity vary it more difficult to determine the amount of CO2 produced from the electricity use to heat water. Most of the electrical generation on the United States is from coal which produces copious amount of CO2. However if you live in a region of the country where hydro is used to generate electricity, which is up to 40% in some areas, your carbon footprint is proportionally reduced. You can inquire with your local power company for the percentages. If your company happens to participate in the green energy options, you should pony up to purchase clean renewable generated electricity. If you are using electricity generated from a wind turbine or photovoltaic muddles for water heating you should have a clear CO2 conscience in relation to your water heating. So whatever your source of energy, if you are using solar thermal as your primary heat source you will achieve a 55% to 85% of you water heating by the energy of the sun. Federal tax incentive can help offset the cost of a single tank system and many states, cities and local utilities have incentives as well. The current federal tax credit pays 30% of a solar hot water system costs up to $2000. Most qualified systems must be installed and operational by December 31, 2008 to receive the federal tax credit. At least a dozen states offer incentives based on the cost or performance. You can also contact your local utility or solar contractor to find out what is available. Now your ready to start living green Sky Realty is your choice for Green living. Steve Aubin knows about Eco Affordable real estate such as Las Casas Verdes.