No. The air space you're looking into above Insert is between the firebox and outer casing of Insert. The back half of Insert is double wall. The original installation of the Insert was slid into fireplace and allowed to exhaust up existing fireplace chimney flue. That would be the space behind face plate that also needed to be sealed to hearth front very well so ALL air going up flue had to go through Insert box via the air intakes to feed fire. Now all Inserts should (must) be directly connected to a liner, so the space behind face plate is a dead air space. The most heat from a blower comes from around the exhaust outlet pipe that you can see looking through the air slot across top of insert. That airspace is open down the back and under insert with opening for intake under ash fender. (shelf) Some face plates have slots on the sides that are close to the firebox. These go into the same air space between firebox and outer shell to blow air out the top. Only the back half of Insert has the double wall with air space to heat with convection. The front that sticks out and doors heat by radiation. The object is to move the heat with the air, not radiate rearward. The outer shell in rear will get warm, but not overly hot to heat the area behind it.
![[Hearth.com] Made a Blower for My Fisher Insert](https://www.hearth.com/talk/data/attachments/172/172753-4e5bd318c08b830d500aaa26d1e69fce.jpg?hash=k45egz5iOH "[Hearth.com] Made a Blower for My Fisher Insert")
Here is one removed so you can see the airspace you want to move air out of by blowing into slot at bottom or sides. Fashion a little duct work to connect your blower to the slot across the bottom.
