The used oil from the Key Hyundai service department heats their work area.
Changing car oil is a dirty job that most people have done at a dealership or service center instead of doing it themselves.
Those businesses are required to recycle used oil and most places pay another company to haul it off to a processor, but not Key Hyundai.
The dealerships in Milford and Manchester keep the oil at the shop and reuse much of it for heating.
In the course of a year, each shop handles about 8,000 gallons of used oil.
"There are companies that will come and pick up the oil, but there are tons of disadvantages to doing that," Jill Merriam, owner of Key Hyundai, said.
The disadvantages include the risk of the company transporting the oil spilling some. When that happens, the dealership is held liable for spill and the amount of diesel the truck hauling the oil uses.
Key Hyundai uses a special furnace to burn used motor oil to filter out sediment. The furnace is expensive, but it has more than paid for itself and is saving the dealership thousands of dollars each month for heating during the winter.