Hearthstone Green Mountain 90 Wood Insert

Flush cast iron design

The flush cast iron front of the GMI 90 is available in matte black or our brown enamel finish.

Soapstone firebox

Burn up to 20 inch logs in the soapstone lined firebox. Soapstone retains the maximum heat from you fire and radiates steady warmth as your insert burns.

Simple operation

Our non-catalytic wood insert is easy to use. A single lever air control lets you burn hot and fast or low and slow to keep warm through the night.



Our non-catalytic large flush insert combines stylish cast iron with our signature soapstone lining..


Maximum BTUs/hr 80,000
Heats Up To 2,200 sq ft
Efficiency 64%
Product Size Large
Log Size 20″
Burn Time up to 8 hrs
Firebox Capacity 2.5 cu. ft.
Emissions (gms/hr) 1.22
Room Size Large
Vent Type Stainless
Vent Size (Exhaust) 6″
Sliding Front Yes, Only At 0″- 2″- 4″
Masonary Fireplaces Only Yes

Appliance Dimensions

Width 31 3/4″
Height 22 3/8″ At The Back
Depth 21 1/2″

Hearth Requirements

Insert At Flush Depth 16″ Of Hearth Is Needed
Insert At Extended Depth (2″ or 4″) 18″ or 20″ Of Hearth Is Needed

Surround Sizes

Standard 38 1/2″ Width X 28 3/4″ Height
With Surround Extension 50″ x 34 1/2″

Mantle Clearances

Clearance Required 40 3/4″ Mantle Sticking Out Up To 12″

Minimum Fireplace Opening

Width 31 3/4″″
Height 27 1/8″
Depth 22 1/8″