Is It Safe to Use a Gas Fireplace That Hasn't Been Used in Years?

Most of the calls we get about this come from one of two places. Either the fireplace came with a house that was just bought and nobody knows its history, or it is the family's own fireplace and it simply has not been turned on for two, five or ten years because lighting it was a hassle or nobody got round to it.

Both end at the same question: can I just turn it on? The honest answer is that the fireplace probably still works, and that working is not the part to worry about. What years of sitting do is change the things you cannot see, and those are the things that decide whether it is safe.

The pilot and burner get blocked. Spiders and other insects build webs and nests in the small pilot tube and burner openings of a fireplace that is not being used, and dust and pet hair settle on top. A partly blocked pilot gives a weak flame that will not hold, and a partly blocked burner gives a dirty, yellow flame. This is the single most common thing we find on a long-idle unit.

The vent can be blocked or disturbed. Outside, the vent termination is an inviting spot for a bird or a wasp nest. And if the house has had a new roof, new siding or a remodel since the fireplace last ran, the vent may have been knocked loose, covered or partly disconnected without anyone noticing. A blocked or damaged vent is the cause that turns this from an inconvenience into a carbon monoxide question.

Sensors and seals age even without use. The thermocouple or thermopile that proves the pilot is lit weakens over time, and the gasket that seals the glass on a direct-vent unit hardens and shrinks. Both are covered in more detail in our guide on whether a gas fireplace really needs annual service.

Batteries die and corrode. Many remotes, wall receivers and electronic ignitions run on batteries. After years in a drawer or a wall box they are flat or have leaked, and a fireplace that will not respond to the remote is often nothing worse than that.

Someone may have changed something. On an inherited fireplace the logs may have been moved or put back in the wrong order, the gas may have been shut off at a valve, or parts may have been swapped without a record. None of that is unusual. It just means nobody should assume the unit is set up the way the manufacturer intended.

A light, dusty or slightly hot smell for the first several minutes is normal. Dust burns off the burner and the firebox, and a new or long-idle unit can also give off a faint smell as residue on the metal heats up. It should fade quickly and not come back on the next fire.

What is not normal: a smell that lingers or makes eyes sting; a smell of gas (the rotten-egg odor added to natural gas) at any point; soot on the glass, the logs or the wall above; a flame that is tall, yellow and lazy where it should be lively; a pilot that keeps going out; or anyone in the room getting a headache or feeling drowsy while it runs. Any of those means turn it off and have it looked at before using it again. Our guides on a yellow gas fireplace flame and a pilot that will not stay lit go into those two in detail.

A general home inspection usually notes that a gas fireplace is there and may say whether it lit, but it is not a gas appliance service. It does not normally include cleaning the pilot and burner, measuring the sensors, checking gas pressure, inspecting the vent run end to end or taking a carbon monoxide reading with the unit running. If your inspection report says something like "recommend evaluation by a qualified professional" about the fireplace, that is the report telling you it did not go further. Our guide on inspections when a house changes hands explains why that line appears so often.

It also helps to know what you have. The make, model and whether the unit is vented are on a metal rating plate, usually behind the lower louvre panel or under the logs. A photo of that plate tells us the type of system and which parts it takes before we arrive, and our gas fireplace brands guide explains where to find it and why the ignition type matters more than the brand.

We look at the pilot and burner flame first, then clean the pilot assembly and burner ports, set the logs back in the positions the manufacturer specifies, test the thermocouple or thermopile, igniter and valve with a meter, check the gas connections and pressure, inspect the vent and its termination outside, check the glass and gasket, and take a carbon monoxide reading with the fireplace running.

On an older unit we will also tell you plainly whether it is worth repairing. Most long-idle fireplaces need a cleaning and sometimes a sensor, not a replacement. Where a part is no longer made for an old model, you hear that before any money is spent on it.

The inspection is a flat 69 dollars anywhere in the metro with no trip charge, with a written report and photographs. If something needs repairing you get one fixed price in writing first, and the 69 dollars comes off it in full.

It is tempting to turn the gas on, hold the knob and find out. The trouble is that the things most likely to be wrong after years of sitting, a blocked vent or a dirty burn, are exactly the ones that do not show themselves in the first few minutes, and carbon monoxide has no color and no smell. Keep a working carbon monoxide alarm near the fireplace, have the unit checked before its first fire, and if you ever smell gas, do not operate the fireplace or nearby light switches, leave the house, and call Spire at 800-887-4173 or 911 from outside.