Since your fireplace is not against an outside wall, that does pose complications. A direct vent fireplace would be complicated and costly to install. But you might consider a direct vent gas stove, either cast iron or soapstone. These are free-standing units that have to be some distance from combustible surfaces (the wall behind and on either side of the stove), and they have to stand on a noncombustible surface such as brick, tile, or slate. There would be a chimney that goes up from the rear of the stove to the ceiling, through the ceiling, and continuing on through the roof to the outside. If yours is a 2-story house, the cost would of course be higher than if it is a on-story house, and you'd have to figure out where the chimney would occupy space in your upper floor(s), peferrably in a closet where it would not be seen. A friend of mine had such a system in their 2-story house, but it was planned before construction, whereas yours would be retrofitted. All of this sounds complicated and expensive, and probably is, which is probably why the previous owner put in ventless. Although electric would not give you the kind of performance you get from gas, I would not dismiss it. Some electric units are pretty good. Just stay away from gas ventless.

Greg here from Hansen Wholesale, where @tigerdunes purchased his ventless logs. I am also the one who has published all of the details at the Hansen Wholesale website regarding the pros and cons and differences between vented and ventless gas logs. Truth is, there are many considerations and we handle each case separately when dealing with our customers. In some cases, ventless makes sense, but in most cases vented gas logs are the best choice. The original thread here is 3 years old, but as I read the entire thread there is some confusion about welding the damper open when installing a direct vent gas log. I think Anapolitan may have confused "Vented" gas logs with a "Direct Vent Insert". There are no "Direct Vent Gas Logs". Direct vent refers to sealed metal box that you insert into the fireplace. There are two ducts that get run up the chimney with a special chimney cap installed at the top. One vent draws outside air down the chimney for combustion while the other is used for exhaust. It is an air tight sealed unit. Because there are 2 ducts, the damper would have to be propped open to feed the ducts up the chimney. Vented gas logs require that the damper is open when they are burning. Some municipalities may require you to weld the damper open when using a vented gas log. The reason vented logs need the damper open is because they burn more like real wood where they intentionally do not completely burn the gas. This creates a wafty yellow flame very much like real wood. It also produces Carbon Monoxide (lethal gas), Carbon Dioxide, Water Vapor and Soot. Hence the reason the damper needs to be open. With the damper open, most of the heat goes up the flue. Because ventless logs burn the gas completely, at least in an ideal situation, the byproducts are Carbon Dioxide and Water Vapor, neither of which present a health issue when used in moderation. Since the damper is closed, 99.99% of the heat produced by burning the gas will come into the room, so ventless gas logs produce a LOT of heat, sometimes too much. The R. H. Peterson ventless gas logs are rated as both vented and ventless. Technically, if they are intended to be used as vented logs the damper must be propped open permanently, but most people ignore that. The best solution to the issue of leaving the damper open all the time is to add a glass door to the fireplace so you can close the doors when the fire is off. Anyways, I have much more detail on our website and in the heads of our gas log experts. Anyone reading this may want to talk to us directly because each case really does need to be handled on an individual basis. Profided by: Greg Tillotson Hansen Wholesale: Gas Logs and Fireplace Doors Feel free to email me directly. If you do, be sure to include some pictures of your fireplace along with the inside dimensions: gregt@hansenwholesale.com P.S. If this comes through all in bold, I tried turning the bold off, but it wouldn't listen.

You couldn't give me a ventless fireplace. We have a second house with one. They deplete the oxygen in the house and when operation they emit lots of water (probably not an issue in AZ) carbon dioxide and other small amounts of combustion by products. while I don’t normally suffer allergies there are three things that cause a slight asthmatic like symptoms in me: dogs, mold and ventless fireplaces. These units all have oxygen sensors which is a primitive electomechanical device which is supposed to shut down the heater when the O2 level drops to low. When not operating properly they can like any combustion device emit carbon monoxide. When we rented the property we had to disconnect it beacauss local codes prohibit these in rental properties. I believe most building codes near me prohibit new installs in any property .

Vent and exhaust are often used interchangably in building construction but not in building codes. In building codes a "vent" is a required system integral to a gas appliance that allows all by-products of combustion and some indoor air to exit the house by gravity or fan through a single-wall UL-rated metal duct. The codes consider a gas cooking range to be "vented" to the room and consider a fan driven hood above the range be an optional "exhaust" that recirculates air to the room or forces it to the outside. A bathroom fan is considered an "exhaust" to the outside. A "direct vent" gas fireplace is a closed system that draws outside air through a vertical or horizontal double-wall duct to a glass-fronted firebox and allows that air to return to the outside along with the by-products of combustion in the inner part of the double-wall duct. The odor of gas indicates the presence of unburned fuel from a malfunctioning gas appliance. CO is so incredibly dangerous because its odorless. One of my clients had a masonry wood burning fireplace removed and the contractor didn't realize the chimney was illegally shared with a gas-fired swimming pool heater. She had headaches and some nausea every morning but it wasn't unitl the flowers that had been delivered for a party wilted overnight that she called her husband who was a doctor and he told her to leave the house immediately and wait for the ambulance.