The cost to switch from oil to gas heating can vary widely depending on factors like the location, existing infrastructure, size of the home, and specific project requirements. On average, the cost can range from $4,000 to $15,000 or more. This typically includes expenses for removing the old oil equipment, installing a new gas furnace or boiler, updating gas lines and venting, and potentially modifying the chimney. Additional costs might arise if extensive modifications are needed or if permits are required. To get an accurate estimate, it's recommended to consult with HVAC professionals and obtain quotes tailored to your situation.