The best choices for shoppers searching for multi-fuel fireplace inserts are dual-fuel gas models that can use either natural gas or liquid propane. The Duluth Forge FDI32R is best for a straightforward insert with remote control, while the FDF400RT-ZC adds double doors and a brick-look liner. The Comfort Glow is a log-set option, and the LegendFlame is an electric alternative—not a gas or dual-fuel appliance. “Multi-fuel” can mean different things, so check the fuel type and installation requirements before choosing.
| Product | Fuel or format | Best for |
|---|---|---|
| Duluth Forge FDI32R | Natural gas or propane | Remote-controlled dual-fuel heating |
| Duluth Forge FDF400RT-ZC | Natural gas or propane | Double-door insert styling |
| Duluth Forge DFS-400R-2AS | Natural gas or propane | A fireplace and mantel in one unit |
| Comfort Glow Log Insert | Natural gas or propane | A vent-free log-set format |
| LegendFlame 60-Inch Electric | Electric | Smart controls and decorative flames |
Duluth Forge FDI32R Dual-Fuel Insert
Best for: Buyers who want the option to use natural gas or liquid propane and prefer remote operation. The listed 32,000-BTU output and remote with LCD screen make this a feature-rich option among the gas inserts in this selection.
The manufacturer describes this as a vent-free insert that needs no outside duct or chimney and is rated to heat up to 1,500 square feet. It includes manual flame adjustment, a standing pilot, nine hand-painted ceramic-fiber faux logs, and a mesh screen.
Why it was selected: It directly fits the dual-fuel search intent while offering remote on/off control and two fuel options. The faux-log design is intended to give the firebox a traditional appearance.
Consider: This is a ventless gas appliance, not a wood-burning or electric insert. Confirm that its installation and vent-free operation meet local requirements and suit the intended room before buying.
Duluth Forge FDF400RT-ZC Insert
Best for: Buyers who want dual-fuel operation with a more finished, enclosed-looking front. Like the FDI32R, this model is listed at 32,000 BTU, can use natural gas or liquid propane, and includes a remote with an LCD screen.
The feature list describes a vent-free design rated to heat up to 1,500 square feet without an outside duct or chimney. It has six hand-painted ceramic-fiber faux logs, mesh double doors, and a sprayed brick liner. Flame adjustment is manual.
Why it was selected: It provides the same listed fuel flexibility and heating output as the FDI32R, but its double doors and brick-look liner distinguish its appearance. Choose it if those visual details are a priority.
Consider: The listed controls specify manual flame adjustment; do not assume that the remote provides thermostat control. As with any vent-free gas insert, check applicable local rules and installation instructions.
Duluth Forge DFS-400R-2AS With Mantel
Best for: Buyers who want a fireplace unit with a furniture-style mantel rather than an insert alone. It offers natural-gas or liquid-propane operation, a listed 32,000-BTU output, and remote control.
The product is described as vent-free and rated to heat up to 1,500 square feet without an outside duct or chimney. Its remote supports switching between manual and thermostat control to set a desired temperature. The design includes six ceramic-fiber faux logs, double doors, a sprayed brick liner, and a furniture-grade mantel in an Apple Spice finish.
Why it was selected: This is the most complete-looking option for shoppers who need the mantel as part of the fireplace setup. Thermostat control is a useful distinction from the other Duluth Forge insert listings.
Consider: The mantel means this is not simply an insert for an existing fireplace opening. Check the product dimensions and installation instructions against the space you plan to use.
Comfort Glow Dual-Fuel Log Insert
Best for: Buyers looking for a vent-free gas log set rather than a cabinet-style insert. This model uses either liquid propane or natural gas and has a six-piece, 18-inch concrete log set.
Listed features include a double yellow-flame burner, vent-free design, and thermostatic control. The product description states that it can heat up to 1,250 square feet, which is a lower stated coverage area than the 1,500-square-foot Duluth Forge models.
Why it was selected: It offers both common gas fuel options in a log-set format and provides thermostat control. It may suit buyers who want the appearance of logs without choosing one of the larger Duluth Forge configurations.
Consider: The listed features do not specify a remote control or a 32,000-BTU rating. Check the required firebox dimensions and installation details before treating it as a direct replacement for another insert.
LegendFlame 60-Inch Smart Electric Insert
Best for: Buyers who want an electric fireplace with smart controls and flexible mounting options. This is not a dual-fuel gas model; it is included as an alternative for shoppers using “multi-fuel” broadly to compare different fireplace types.
The 60-inch-wide unit supports wall mounting or in-wall recessing. Its features include 750-watt and 1,500-watt heater settings, multiple flame and fuel-bed colors, a remote, Wi-Fi connectivity, and Alexa and Google Assistant control. The listed overall dimensions are 60 inches wide by 18.9 inches high by 7.8 inches deep.
Why it was selected: It offers a different fuel category from the gas options and may appeal to buyers seeking app or voice-assisted controls and adjustable flame appearance.
Consider: It requires a 120-volt, 15-amp circuit and can be plugged in or hard-wired. It does not use natural gas or propane, so it is not a substitute when gas dual-fuel operation is essential.
Buying Guide: How to Choose a Multi-Fuel Fireplace Insert
What does “multi-fuel” mean for a fireplace insert?
In this selection, “dual fuel” means that a gas appliance is designed to use either natural gas or liquid propane. It does not mean that the insert burns wood, pellets, and gas. Check the product’s specific fuel description rather than relying on the broad phrase “multi-fuel.” The LegendFlame model uses electricity and should be compared as an electric alternative, not as a gas dual-fuel appliance.
Should you choose natural gas, propane, or electric?
Choose a dual-fuel gas model if you need the option of natural gas or liquid propane and the appliance’s installation requirements fit your home. Confirm the available fuel supply and the exact setup instructions for the model. Choose electric if you prefer an appliance powered by a household electrical circuit and want features such as adjustable flame colors or smart controls. These fuel types require different installation planning.
How much heating output do you need?
Compare the manufacturer’s stated heating output and coverage rather than assuming all fireplace inserts heat the same area. The Duluth Forge gas models are listed at 32,000 BTU and up to 1,500 square feet. The Comfort Glow listing states coverage up to 1,250 square feet but does not provide a BTU figure in the supplied features. Room size, layout, insulation, and climate can affect how well a heater serves a space.
Do you need a vent or chimney?
The Duluth Forge and Comfort Glow products in this selection are described as vent-free or ventless. The Duluth Forge listings say that no outside duct or chimney is needed. That feature does not remove the need to follow the appliance’s installation and operating instructions. Check local rules and building requirements before selecting a vent-free product, especially if the unit will be installed in a room with particular ventilation restrictions.
Which controls matter most?
Remote control can make it easier to switch a gas fireplace on or off. The FDI32R and FDF400RT-ZC list remote operation and manual flame adjustment. The DFS-400R-2AS adds a remote thermostat-control option. Comfort Glow lists thermostatic control but does not list a remote in the supplied features. The LegendFlame includes a remote and supports Alexa and Google Assistant through Wi-Fi.
Should you buy an insert, log set, or mantel unit?
An insert-style product may be the better fit when you want a unit designed to go into a fireplace opening, but verify its dimensions and installation requirements. Comfort Glow is described as a log insert with a 6-piece concrete log set. The DFS-400R-2AS includes a mantel, so it is a different style of setup from an insert alone. The LegendFlame supports wall mounting or in-wall recessing; check its dimensions and electrical needs before planning a location.
Frequently Asked Questions
Are dual-fuel fireplace inserts compatible with both natural gas and propane?
The Duluth Forge and Comfort Glow products listed here are described as dual fuel for natural gas and liquid propane. Confirm the product’s fuel setup and instructions before installation; do not assume every gas insert supports both.
Is a vent-free fireplace insert the same as a vented insert?
No. The gas products described here are vent-free or ventless and are listed as needing no outside duct or chimney. Check local requirements and the manufacturer’s instructions to determine whether that style is appropriate for your home.
Which listed gas model includes thermostat control?
The Duluth Forge DFS-400R-2AS lists remote operation with a choice of manual or thermostat control. Comfort Glow also lists thermostatic control, but its supplied features do not specify a remote.
Is the LegendFlame a multi-fuel gas insert?
No. The LegendFlame is an electric fireplace. It supports plug-in or hard-wired electrical connections and is not listed as using natural gas or propane.
What should I check before purchasing an insert?
Check the fuel type, product dimensions, heating output, controls, and installation requirements. For gas models, verify the intended fuel supply and local rules. For the LegendFlame, confirm that the required 120-volt, 15-amp circuit and chosen mounting method suit the installation location.