Resources Geothermal is an excellent way to heat and cool your Wilmington home or business. We have years of experience backed by WaterFurnace brand geothermal products. We are sure you have questions on how geothermal can work for you. Don't worry, we're here to help. You'll find a lot of valuable information and resources here... Geothermal Incentives Geothermal Savings Calculator F.A.Q.s Still have questions on how a geothermal system can help you here in Wilmington? Just give us a call or email us and we'll be happy to help you on your path to a more energy efficient and cost saving way to heat and cool your home or business. O'Brien Service Company and WaterFurnace, "Smarter from the Ground Up!"