Masonry and prefabricated fireplaces can be fueled by wood, natural gas, biomass and propane fuel sources. Ventless Fireplaces (duct free/room-venting fireplaces) are fueled by either gel, liquid propane, bottled gas or natural gas. In the US, some states and local counties have laws restricting these types of fireplaces. They must be sized appropriately to the area to be heated. There are also air quality control issues due to the amount of moisture they release into the room air, and oxygen sensor and carbon monoxide sensors are safety essentials. Direct vent fireplaces are fueled by either liquid propane or natural gas. They are completely sealed from the area to be heated, and vent all exhaust gasses to the exterior of the structure.

Chimney and flue types:

Masonry (brick or stone fireplaces and chimneys) with or without tile-lined flue.

Reinforced concrete chimneys. Fundamental design flaws bankrupted the US manufacturers and made the design obsolete. These chimneys often show vertical cracks on the exterior.

Metal-lined flue: Double or triple walled metal pipe running up inside a new or existing wood-framed or masonry chase.

Newly constructed flues may feature a chase cover, a cap, and a spark arrestor at the top to keep small animals out and to prevent sparks from being broadcast into the atmosphere.