Unvented / Vent-Less Heaters

With energy costs rising, many people are looking at alternative heating arrangements. As a general rule, anything that burns with an open flame (wood stove, natural gas, LP-Gas, etc.) should be vented to the outside of the building. This prevents the build-up of deadly Carbon Monoxide (CO) in the building.

Several manufacturers have developed unvented (or vent-less) heaters. These are used for supplemental heat (such as space heaters), for decorative and heating purposes (such as certain gas fireplaces), and for specialized or localized heaters (such as tank-less water heaters). These are commonly sold at hardware and home-improvement stores.

These unvented (or vent-less) heaters are prohibited in most occupancies by the state fire or mechanical codes. This includes only heaters with an open flame; it does not include electric space heaters (no open flame).

The state fire code allows these types of heaters in homes but they cannot be located in or take their combustion air from bedrooms, closets, or bathrooms.

By using an internet search engine and typing in “unvented heater”, you will get many examples and pictures of unvented (or vent-less) heaters.

For all types of space heaters (electric or open flame), combustible materials (wood, paper, plastics, etc.) should be kept at least 36 inches away.

For additional information, contact Robert Dahm, Minnesota State Fire Marshal Division