Which appliances are NOT required to be vented?

Direct gas-fired make-up air heaters are not required to be vented because they are designed to directly heat incoming air for ventilation purposes without creating exhaust gases that need to be vented outside. These systems optimize energy efficiency by using the heat generated without the need for additional venting systems to remove combustion byproducts, as is often necessary for other gas appliances. This characteristic makes them suitable for applications where ventilation air is needed while maintaining indoor air quality and energy efficiency.

In contrast, electric ovens, gas stoves, and commercial dryers generate byproducts from combustion or other processes that must be safely removed to prevent toxic build-up and ensure safety and comfort within the space.