Due to rising interests of utilizing energy more efficiently, new ways of maximizing the efficiency in heating and cooling systems are being explored. Although natural gas furnaces and central air conditioners are the most common heating and cooling systems used, geothermal heat pumps are also being used more. There are also two new technologies that use solar energy as the primary source of energy to power these heating and cooling systems. One system is an absorption air conditioner unit that uses direct solar heating, and the other is called a thermally driven heat pump. There are several computer programs that simulate the two common systems; however, there are no known programs that calculate the energy and cost during operation for the systems that use solar energy.

Because there are no models that predict the cost and energy usage of all four systems, an Excel™ workbook was developed to analyze all four of these systems in the same home figuratively placed in five different U.S. cities. These cities represent the different climate regions in the country since the heating and cooling loads will vary depending on the climate of the city the home is in. The workbook allows one to enter data and from that data determine which system will be cost-effective compared to a condensing gas furnace and high-efficiency central air conditioner assembly. It also determined what the costs of natural gas and electricity will have to rise to in order for certain systems to be cost-effective. Based on a life cycle cost analysis, the results show which system to choose for the residence.

The results show that the vertical ground source heat pump always paid back the quickest in all five cities. The absorption unit never paid back in any of the cities. The thermally driven heat pump paid back in Louisville, Kentucky and Minneapolis, Minnesota. Increasing the energy costs and decreasing solar panel costs independently to get the solar-powered systems to pay back within twenty years showed that these increased energy prices or decreased solar panel costs are probably unlikely.