Sterling has been a leader in the gas heater industry for over 50 years. Sterling unit heaters are well known for being highly efficient, reliable, and durable. These gas heaters are available in sizes ranging from 30,000 to 400,000 BTUs in both standard and separated combustion setups. Whether your application is a greenhouse, garage, shop, or warehouse, Sterling has a gas heater to fit your needs. Sterling gas heaters are made in the USA.