Gas Fireplace Inserts

What Is a Gas Fireplace Insert?

A gas fireplace insert is a complete heating unit that fits inside an existing wood-burning fireplace. It closes off the old open firebox and turns it into an efficient, easy-to-use heater with a realistic fire. The term can mean several different products, so read our short explainer, what is a fireplace insert?, if you are not sure which one you need.

Vent-Free Inserts vs. Vented Inserts

Vent-free inserts, such as the Monessen DIS33 on this page and the Empire Innsbrook and Empire Loft inserts, need no chimney liner and send nearly all of their heat into the room. They must follow vent-free sizing rules and local codes.

Direct-vent inserts use flexible liners run down the existing chimney to bring in outside air and send exhaust out. They are a good choice where vent-free appliances are restricted. See our direct-vent fireplaces page for how sealed-combustion venting works.

How to Measure Your Fireplace

Before you order, measure the fireplace opening: the front width, the back width, the height and the depth from the opening to the back wall. Compare those numbers with the minimum opening dimensions in the insert’s specification sheet. Have the chimney and firebox inspected and cleaned, and plan for a gas line to be run by a qualified gas technician. Many inserts, including the DIS33, can also be installed as a zero-clearance fireplace in new framing.

No Fireplace? Consider a Gas Stove

If you do not have a fireplace, a freestanding gas stove gives you the same cozy fire anywhere you can run a gas line. Compare Empire cast iron gas stoves, Monessen vent-free cast iron stoves and the Empire insert and freestanding stove.

For questions about air quality, operation, safety and sizing of vent-free appliances, see Let’s Clear the Air or visit the Vent-Free Gas Products Alliance at ventfree.org. Prices shown come from our last catalog update; call to confirm current pricing.

Getting the Most Heat from an Insert

An open wood-burning fireplace often sends much of its heat up the chimney and can pull warm air out of the room. A gas insert closes off the opening and directs heat into the room instead. Choose an insert with a blower if you want warm air to reach farther into the room, and consider a thermostat or remote control so the insert can turn itself on and off to hold a comfortable temperature.

Finishing Touches

Inserts come with face plates or surrounds that cover the gap between the insert and the fireplace opening. Measure carefully so the surround covers the opening fully. If you are remodeling at the same time, a new wood mantel can complete the look.

Frequently Asked Questions

Will a gas insert fit my fireplace?

Most inserts fit standard masonry fireplaces, but you must check your fireplace’s front width, back width, height and depth against the insert’s minimum opening dimensions before ordering.

Do I need a chimney liner for a gas insert?

A vent-free insert does not need a liner. A direct-vent insert needs a liner kit installed in the chimney to bring in outside air and carry exhaust out.

Does a gas insert work without electricity?

Inserts with manual or millivolt controls light and run without household power. The automatic blower needs electricity, so it will not run during an outage.