Non-vent (vent-free) Gas Fireplaces and Stoves

Non-vent gas fireplaces and stoves are cheap and efficient heating appliances, running without a chimney or flue, allowing an easy installation in most places in the house.

They are increasingly popular options, due to their price and versatility but they involve concerns and potential environmental and health hazards that you should take into account. Many states have forbidden non-vent appliances...

How they work

Non-vent fireplaces and stoves are fueled by natural gas or propane. These fuels flame through a line connected to a ceramic plaque or other type of burner.

The Inside air quality issue

Today's non-vent appliances have low emission levels of carbon monoxide, nitrogen dioxide and other combustion by-products. But they can affect indoor air quality negatively. Even the water vapor produced by these heaters may have a negative impact on air quality, mainly in modern well-insulated homes, if the appliance is operated often and for long periods.

Symptomatically, some states restrict or forbid vent-free fireplaces and stoves.

Avoiding problems

To avoid the air quality problem, most vent-free stoves and fireplaces manufacturers recommend short operating times. They shouldn't exceed three hours per day. Also to avoid problems, the heat output of these appliances should not exceed 40,000 Btu/hr.

Oxygen Detection Safety-Pilot

Modern non-vent appliances are equipped with an “Oxygen Detection Safety pilot” (ODS), in order to increase their operational safety. These devices will shut off the gas supply whenever the oxygen level in the room falls below normal levels.

Alternatives to Vent-free Fireplaces and Stoves

Vent-free fireplaces and stoves are efficient and inexpensive appliances, but there are safer and environmentally better options. Direct-vent gas heating options, or pellet stoves and fireplace inserts… are between those alternatives.