At Your Service Heating & Cooling LLC provides geothermal HVAC in Baltimore, MD, to residents who wish for a better home ambiance. Geothermal heating and cooling systems use modified heat pump technology to extract the natural underground heat to warm your home in winter. Conversely, it extracts heat from the indoor air in summer and disperses it into the ground. This type of system provides great indoor comfort, making it an efficient source of warm and cool temperatures as needed.