The popularity of gas fireplaces is undisputed. Whether it’s natural or LP gas, the realism of the fire in many gas hearth products is outstanding. Homeowners enjoy the convenience and the versatility of a gas fireplace.
But what about when the chips are down and an ice storm, heavy snows or high winds cause a power outage? Can a gas fireplace be expected to heat? A forced air furnace will not operate without power. Can my gas fireplace?
Before we answer this question, let’s get a better understanding of how your gas fireplace works.
HOW DOES YOUR GAS FIREPLACE START?
When you flip a wall switch, click on your remote control or the thermostat calls for heat, the gas valve on your fireplace will open. Gas valves generate their own electricity and operate on millivolts, a very small amount of electricity. That’s substantially less that the 120 volts that are needed for many appliances, rechargers and lamps that plug into an outlet in your house.
PILOT LIGHTS AND MILLIVOLTS
Millivolts of electricity are generated by a small device called a thermocouple. Basically, a thermocouple is a sensor that measures temperature. It’s made with two different types of metals. Several of these thermocouples connected together are called a thermopile. A thermopile is about the diameter of a pencil and a couple inches long. A small wire connects it to the gas valve.
A pilot light, or a very small gas flame, heats one end of the thermopile. Since one end is hotter than the other, the difference produces a temperature dependent voltage. That voltage is millivolts of electricity whose purpose is to open and close the gas valve. (It’s worth noting here that the normal position of a gas valve is closed. Without being supplied millivolts of electricity, the gas valve cannot open and will remain in the closed position.)
A pilot light has two functions. One is to generate millivolts in order to open and close the gas valve. Once the valve is open, the second function is to ignite the fuel as it flows into the burner assembly.
TWO TYPES OF IGNITION SYSTEMS
Hang on, we going to get to the original “will it operate without power” question in just a minute! But first, a few details and a bit more background information.
For many years, “standing” pilot lights were kept burning 24/7/365 in fireplaces, water heaters and furnaces. This type of technology has been around for years and has been proven to be very reliable and consistent in its performance. However, since the pilot is always lit, this is considered wasteful by some. As a result, electronic ignition was developed.
An electronic ignition system does not utilize a standing pilot light. The pilot is on, only when the fireplace is operational. After using a wall switch or remote control, an on-demand, electric source creates a spark and ignites the pilot light. This type of ignition system is called IPI, or Intermittent Pilot Ignition.
WHICH TYPE OF IGNITION SYSTEM IS BETTER?
Either type of system, millivolt or IPI will start your fireplace. In the event of a power outage, the millivolt system will operate normally. The IPI system will operate normally providing the fireplace has back-up batteries.
Pros and cons of each system? A millivolt system is a proven technology that’s time tested and very reliable. It’s a simpler method to ignite the fireplace. But, is it wasteful?
There are a couple distinct advantages for keeping a pilot light on year-round. If you live in a damp or humid climate, there’s a very small amount of heat generated by a standing pilot light. This can keep the inside firebox dry and prevent rust from developing. A standing pilot light can prevent small, silky spider webs from forming inside the fireplace, that may result in a service call to get the fireplace back in service.
An IPI system is going to be more “efficient” since fuel is used only when you flip a wall switch or click on your remote. IPI is a more complicated system. It requires an electric source to create a spark that ignites the pilot light. If the power is out, the fireplace will not ignite. However, most gas fireplaces use a battery back-up for an IPI ignition system.
Today, many fireplace manufacturers produce units in both millivolt models and IPI models. There are some states where IPI technology is mandatory. Other states will allow either type of ignition.
A standing pilot gas system is less expensive than an IPI system. IPI uses newer technology and can be more difficult to troubleshoot than a standard millivolt system in a fireplace. Many service techs would tell you that they prefer a millivolt system over an IPI system in a fireplace. There’s a lot less to go wrong in a millivolt system.
Operating costs of a millivolt system is approximately 4.5 therms of natural gas or about 5 gallons of LP gas per month. Gas rates vary a lot depending on the time of year and regionally. As this article was written, in the Midwest, this gas usage would equate to about $4.00 - $5.00/month for natural and about $5.25 - $6.25/month for LP.
FINALLY, WHAT ABOUT HEATING DURING AN OUTAGE?
Either type of ignition system will operate in the event of a power failure. Depending on the size of the gas burner, a substantial amount of radiate heat can be generated from the fireplace. This radiate heat from the appliance will warm the objects in the room.
On the other hand, without power to the house, no convective heat will be felt. A common question that dealers are asked: Will my blower fan operate with the power out. The answer is no. Fans are reliant on house current and if the power is out your house, regardless of the ignition system, the fan will not operate.