How the Active Heat Flex System Works

Linear and traditional gas fireplaces need a heat release grille in the wall. This grille exhausts the warm air that builds up above the firebox. However, it also forces design compromises. It limits your finishing materials, dictates wall layouts, and rules out a TV above the fireplace. The Active Heat Flex removes that constraint entirely.

The Active Heat Flex system captures rising heat above the fireplace and sends it outside through fan-powered ducting. A sheet metal topper gathers the heat. A built-in temperature sensor then monitors the airflow and keeps the system running safely. As a result, you need no heat release opening in the wall. You can frame and finish with combustible materials – provided you follow the required clearances. The outcome is a clean, seamless wall that protects your finishes and gives you full design freedom.

Active Heat Flex Design Page | Active Heat Flex Installation Manual

Front-facing frameless gas fireplace beneath open wall cavity showing dual 4-inch flex ducts for Active Heat Flex heat management.
Modern living room with wall-mounted TV above a long frameless linear gas fireplace—Active Heat Flex exhausts heat outside to protect finishes.

Why Designers and Homeowners Choose Active Heat Flex

  • No heat-release grille – this feature removes a common design constraint. This simplifies elevations and millwork considerably.
  • Use combustible finishes (per clearances) – You can use combustible materials around the opening and for framing. No special treatment needed.
  • TV or art above the opening – Place a TV or artwork as close as 12″ from the glass. Standard setups cannot offer that.
  • Protects finishes and electronics – The system sends heat outdoors. Consequently, surfaces and devices experience far less thermal stress.
  • Quieter installs – The fan runs at bathroom-fan volume. Furthermore, you can mount it up to 80 feet away to reduce noise in the room.
  • Design freedom – It works with linear, corner, and see-through indoor fireplaces alike.
Flare See Through 45 Extra High fireplace with Summit Burner on display at Rio Grande Co. Design Center in Denver, Colorado.
Flare Right Corner 100 fireplace display at Rio Grande Co. Design Center in Denver, Colorado.
Flare Passage See Through fireplace display at Rio Grande Co. Design Center in Denver, Colorado.

Key Installation Clearances

Always verify against your local building code and the NFPA 54 natural gas installation standard. Minimum requirements for the Active Heat Flex system are:

  • 40″ min. from the fireplace to non-combustible fire stop.
  • 3″ min. from sides and back of the fireplace to wood framing.
  • 3″ min. to the floor from the underside of the fireplace.
  • 80 ft max recommended fan distance from the fireplace – reduces noise in the room and prevents heat buildup at the fan.
  • 4″ min. from the fireplace to wood header above the unit.

Who Benefits Most from Active Heat Flex?

The system is the right choice whenever a project needs a clean wall, combustible materials near the fireplace, or have less desire for heat.

For example, here are the most common use cases:

  • Customers who desire aesthetic over heat – The Active Heat Flex removes the majority of heat created leaving a fireplace providing pure aesthetics for year-round use.
  • TV-above-fireplace installations – The system lets you place a TV as close as 12″ from the glass. Standard heat-release setups simply cannot match that.
  • Stone, tile, or wood-paneled surrounds – You can run combustible finishes all the way to the fireplace opening. Simply follow the clearance specs and you are good to go.
  • Hospitality and commercial projects – Lobby fireplaces look best with floor-to-ceiling finishes. The system makes that possible without grille interruptions.
  • Renovation projects – Sometimes the wall layout cannot fit a new heat-release grille or does not allow for covering the inside of the fireplace chase with non combustible materials. In that case, Active Heat Flex is the ideal solution.

Additionally, Active Heat Flex works with all Flare indoor fireplace styles – Traditional, front-facing, corner, double-corner, and see-through – in both natural gas and liquid propane.

Frequently Asked Questions

Does Active Heat Flex eliminate the need for a heat release opening?

Yes. Active Heat Flex sends heat outside through fan-powered ducting. Therefore, you no longer need a heat release grille in the wall. This removes one of the most common design limits in fireplace installation.

Can I mount a TV above a fireplace with Active Heat Flex?

Yes. Active Heat Flex sends heat outdoors rather than letting it rise. As a result, you can place a TV or display as close as 12 inches from the glass. Standard heat-release setups cannot offer that clearance.

Can I use combustible materials around the fireplace with Active Heat Flex?

Yes, provided you follow the clearance specs. Keep wood framing at least 3 inches from the sides and back of the fireplace. Also, maintain a 4-inch gap from the wood header above the unit. Within those clearances, you can use wood paneling, millwork, and similar finishes freely.

How far can the fan be from the fireplace?

You can mount the fan up to 80 feet from the fireplace. Moreover, placing it farther away lowers noise in the room and prevents heat buildup at the fan. Both outcomes matter in high-end residential and commercial projects.

Can the active fan be turned off in cold days?

No. As the fireplace is installed with no heat release and is designed for Cold Wall Technology, the fan will need to run any time the fireplace is running. If the fan is accidentally turned off , the fireplace will not run.

Which Flare models work with Active Heat Flex?

Active Heat Flex works with every Flare indoor fireplace model. This includes traditional, front-facing, corner, double-corner, and see-through styles in both natural gas and liquid propane.