Gas Fireplaces – Introduction

Types
Installation

In a large space, such as a home, a gas fireplace is not an efficient primary heating source. It is better to use an efficient furnace. If you plan to use a gas fireplace as a secondary heat source, however, the EnerGuide label can help you find the most efficient model for your purpose. The EnerGuide label for gas fireplaces is found in fireplace promotional materials, such as sales brochures, or on Web sites.

Gas fireplaces, when compared to traditional wood burning fireplaces, offer homeowners many benefits as secondary heat sources:

• They are easier to use and less work than traditional wood-burning fireplaces.
• They offer the convenience of an on/off switch and a steady fuel supply. With a gas fireplace, when the gas supply is shut off, the fire goes out immediately.
• There is no need to clean your hearth, only the glass, and the home doesn’t get the same mess – ashes, wood chips, bark, smoke and other residue – that it would get from a wood fire.
• Because direct-vent gas fireplaces are sealed combustion units, there is little chance for toxic combustion gases to spill into the home, and efficiency is improved because they use no room air.
• When vented to the outdoors, they produce much less carbon monoxide and particulate emissions than wood fireplaces.

What Types are Available Today?

Much progress has been made in gas fireplace technology in recent years. What you choose will depend on your situation and personal preferences.

Three basic types of gas fireplaces are widely available in Canada: inserts, zero-clearance units and free-standing designs. Your biggest challenge will be sorting through the wide range of models available to select a unit that is as efficient as possible and that suits your particular needs.

• Gas fireplace inserts are meant to be installed in an existing fireplace cavity, to convert a wood-burning fireplace to use natural gas or propane. The gas burner and simulated logs are contained in a special metal housing that fits into the existing fireplace cavity. The unit has a glass front for viewing and a decorative metal trim. Existing chimneys must be relined with an approved vent when a gas insert is installed.

• Factory-built (zero-clearance) gas fireplaces are installed when there is no existing fireplace, typically during new home construction or as part of a renovation project. The simulated logs and burner are inside their own firebox, around which is an inner and outer shell. This type of gas fireplace can be installed inside the house envelope, even against an outside wall. The manufacturer's instructions must be followed carefully in regard to proper clearances from combustibles and approved venting materials.

• Free-standing fireplaces resemble wood-burning stoves. All surfaces are exposed, so these fireplaces tend to be more effective in supplying heat to a home since heat is not lost up the chimney or in wall cavities.

The glass fronts used on all of these gas fireplaces can be manufactured from tempered or ceramic glass. Ceramic glass is slightly better at transmitting infrared heat into the room. However, its principal benefit is that it can better withstand higher temperatures associated with sealed units.

Types of Ignition Systems

In gas fireplaces, an igniter is needed to light the main burner when the fireplace is turned on. One such igniter is a pilot light.  A pilot light is a small gas flame that, on its own, can consume anywhere from 600 to 1500 Btu of gas per hour.  Given that this amount of gas can add up to significant energy consumption over time, it is important to understand the main types of ignition systems employed on gas fireplaces.

Direct Spark Ignition – This is a non-pilot based automatic ignition system that lights the main burners in a fireplace directly using a high voltage spark, when you turn the fireplace on.  This type of igniter uses very little power and is energy efficient.

Standing Pilot – a pilot ignition source that once placed in operation is intended to remain ignited continuously until manually interrupted.  This type of ignition system can significantly increase your annual energy costs as that small gas flame is always burning, whether you turn your fireplace on or not.  You will save energy and money by turning off the pilot light when the fireplace is not being used, especially during the summer, but also when the fireplace is not in frequent use during the heating season.

Intermittent Pilot – a pilot ignition source that is automatically ignited when a fireplace is called on to operate and automatically extinguished when each main burner operating cycle is completed.  This type of system eliminates the need to keep a pilot operating continuously by restarting gas combustion each time a flame is desired. When purchasing a gas fireplace, consider one that does not have a standing pilot light.

Pilot on Demand – a pilot system that provides the user with a ready means of initiating the automatic ignition and extinguishment of a pilot ignition source. The pilot system includes a device that is external to the gas safety combination control and does not require direct interaction with the gas safety combination control by the user. The device to initiate pilot ignition and extinguishment is usually mounted in a location external to the appliance controls compartment or is contained in a remote control device.

Some homeowners prefer a fireplace with a continuous pilot light because it gives them an auxiliary heat source that is not dependent on electricity (i.e., the fireplace will operate even when there is a power failure). If this is your preference, look for a unit with a simple method for shutting off the pilot and a similarly convenient and safe means of relighting the pilot. Do not confuse this feature with most remote control or wall-mounted switches, which often control the main gas flame while leaving the pilot to run continuously.  Some advanced fireplaces may employ battery backup systems for continued operation during a power failure, ask for this feature.

Installation

Whichever design you choose, it should be installed by a heating professional. And you'll want to pay close attention to how the fireplace is vented. It's both a safety and an energy efficiency issue. More details on installation.