Technical Abstract: Greenhouses are used in many climates either for season extension or year-round production, and can be expensive to heat. Greenhouse users and growers are often faced with management decisions that rely on an understanding of how temperature settings, heating systems, fuel types, and construction decisions influence overall heat costs. There are no easy-to-use programs to calculate heating costs associated with these factors over periods of time like full cropping season. In January, 2006, we released a computer program called Virtual Grower that helps calculate heating costs in many U.S. sites. The program relies upon a weather database from the National Renewable Energy Laboratory for basic hourly temperature, light, and wind information with which to use in the calculations. A user can define unique greenhouse design characteristics, such as material and style, select fuel type and define the heating system, create a heating schedule, and finally predict heating costs for typical weather at their location. Shorter-term predictions with weather forecasts of two days or less can be made with the software if there is an internet connection through integration with local weather forecasts. Virtual Grower serves as a platform from which many other feature can be added, such as plant growth and scheduling, or information gathered, such as carbon footprint analysis. Continued development will improve the software and allow users to perform baseline analysis of their heating costs, identify areas to improve, and take some of the guesswork out of energy analysis in unique greenhouses.