Zone 4 western NC build. I am installing a zero clearance wood burning fireplace, the RSF320 http://rsf-fireplaces.com/en/focus-320-woodburning-fireplace . Our great room will have a flat 17′ ceiling. The fireplace chase is essentially within conditioned space until the roofline. This particular fireplace has many options, including blowers that take same-room air in and blow out heated air, add on blowers to hook into your HVAC system, no blowers, and even a heat dump that adds a small inline fan to a duct to run heated air to another room. I had planned on using the blowers in-room and even adding the larger fan to hook up to the HVAC system. However, as I thought about it, and started thinking of my HVAC system, I came up with another route. The fireplace has a really clean look without the louvers you need when you add the internal blower fans(see photo). If you eliminate the blower fans, you need to have an air intake and two “gravity vents”(you can see them up high in the attached photo) so your chase can release heat. You can even add a little in-line fan to the intake duct to increase your flow out the top.

So, to get to the point. What would you think about having the gravity vents up high on the sides of the fireplace chase, near the ceiling, and also add a return to the HVAC system in that area. I plan on using the Carrier or Bryant variable speed heat pump units with variable speed fan coils. Supposedly, these motors use 100 watts of electricity when set to their lowest level. That way, I could circulate warm air around the house very efficiently. This would use less electricity and be far less complex than using the internal blowers and/or their central heat blower kit to circulate heat around the house.

As a bonus, I could also add one small “heat dump” duct with the small inline fan to dump into the mechanical room with the Heat Pump water heater. That would provide some ambient heat to extract in the winter.