Electric or gas: what each one asks of the house

What each kind of unit is

Inside the cabinet of an electric fireplace sit a heater and a lighting effect. The heater is a resistance element with a fan; the flame is light projected through a moving rod or an LED pattern. Units come as plug-in or hardwired models, and they hang on a wall, sit recessed in a framed opening, or slide into an old fireplace as an insert.

Gas fireplaces cover several appliance types, each listed to its own standard. Sealed direct-vent fireplaces and inserts are vented gas fireplace heaters under ANSI Z21.88. Vented decorative fireplaces fall under ANSI Z21.50. Log sets for an existing wood fireplace are ANSI Z21.60 decorative appliances, and vent-free units and log sets are unvented room heaters under ANSI Z21.11.2. Which gas type you are considering shapes everything that follows, so pin it down early.

What the installation involves

An electric unit needs a place to mount it and a supply that can carry the heater. Plug-in units go into a grounded wall outlet, not an extension cord or power strip, according to their manuals, and some call for a dedicated circuit. A new circuit or a hardwired connection is electrical work under NFPA 70, done by an electrician. There is no vent, no gas line and no chimney work.

A gas unit brings more trades into the job. It needs a gas supply, natural gas or propane, run to the appliance to the rules of NFPA 54 and the state Fuel Gas code. A vented unit needs a vent route to the outdoors, either through a wall or roof or up an existing chimney with listed liners, with terminations placed to the clearances the manual and the code set.

The unit keeps its listed clearances to framing and finishes, and the local building department may require a permit. A vent-free unit skips the vent but has to meet the room-size and location rules in section 621 of the Fuel Gas volume.

Heat: comparing like with like

In a gas vs electric fireplace comparison, heat is where the numbers confuse people. Electric heaters are rated in watts on their label, and gas appliances are rated by input in Btu per hour on their rating plate. To compare them, multiply watts by 3.412 to get Btu per hour. A plug-in unit on an ordinary household circuit is limited by what that circuit can supply, which caps its heat output whatever the size of the cabinet.

Gas ratings are input figures, not heat delivered to the room. A sealed direct-vent unit is built to heat the room, and part of its input still leaves with the exhaust. A vented log set in an open fireplace is, by its listing, a decorative appliance, and its exhaust carries heat up the chimney with it. If heat is the goal, compare heater to heater: an electric unit's wattage against a direct-vent heater's rating, not against a decorative set.

Flame, feel and running without heat

A gas fire is real flame behind glass or in an open firebox, with radiant heat you feel on your skin and the look of burning logs. An electric flame is a lighting effect. Some are convincing, some less so, and it is worth seeing the exact model running before you choose.

Electric units have one practical advantage: the flame effect runs with the heater off. If you want the look of a fire on evenings when the room does not need heat, an electric unit gives you that without adding heat or burning fuel. A gas fireplace heats whenever the flame is lit.

When the power goes out

Without household power, an electric fireplace does nothing. A gas fireplace can keep working in an outage, depending on its ignition: a standing-pilot system powered by a thermopile generates its own small current and needs no household power, and some electronic-ignition units run from a battery backup. Fans and blowers stop either way. The manual for a gas unit says which type of ignition it has.

Safety and indoor air

Anything that burns gas produces carbon monoxide, and vented units therefore keep their exhaust sealed away from the room and send it outdoors. Florida Statutes section 553.885 calls for a carbon monoxide alarm near the bedrooms of any building constructed from July 1, 2008 on that has a fireplace, a fuel-burning heater or another source of carbon monoxide, and homes built before that date benefit from one just as much. Vent-free units release their combustion products and water vapor into the room, within the limits the Fuel Gas volume sets.

Electric units burn nothing, so there is no exhaust and no carbon monoxide. Their risks are electrical: an overloaded circuit, a warm plug or a pinched cord. Both types have hot surfaces. Gas fireplaces made since the barrier requirement in the two vented fireplace standards took effect in 2015 carry a screen over the hot glass.

Where each one can go in the house

An electric unit can go wherever the wall, the mounting and the circuit allow, bedrooms included, since it has no exhaust. Gas units are placed by the Fuel Gas volume's location rules. Section 303.3 bars gas appliances from bedrooms and bathrooms unless an exception applies. Sealed direct-vent appliances installed as their listing requires are one exception. Vented gas fireplaces, vented log sets and other vented decorative appliances are another, but only in a room whose volume satisfies section 304.5.

Vent-free gas units get only a narrow exception in those rooms, a single small wall-mounted heater with an oxygen depletion safety system. For a bedroom fireplace, an electric unit sits outside these gas rules; a gas unit has to fit one of the exceptions, and a sealed direct-vent unit is the one that does not depend on the size of the room.

Care and servicing

Upkeep on an electric unit is light: grilles kept free of dust and, over time, a bulb, an LED assembly or a fan replaced. A gas fireplace needs more. Gas unit manuals ask for a service technician to inspect the appliance before first use and every year after, and under NFPA 211 the vent and the fireplace get a yearly inspection as well. Glass needs cleaning, pilots and burners need attention, and the vent termination has to stay clear.

Neither choice is wrong. Electric suits a house with no gas service, no vent route, or an owner who mainly wants the look. Gas suits an owner who wants real flame and substantial heat and has a gas supply and a way to vent. Whichever you choose, expect every trade the job needs to be named in the written estimate.