Gas fireplace logs: vented or vent-free? Text

When you convert a wood-burning fireplace to gas, you get to choose the style of your new gas logs and the pattern of the flame.
First, though, you choose whether to buy logs that require a vent for the gas byproducts, or logs that allow you to burn them without a vent.
Vented gas logs
If you’re converting a wood-burning fireplace to gas, and the fireplace has an operating chimney, Rosie recommends vented gas logs.
Once plagued by a “fake” look, today’s vented logs, combined with multiple burners underneath, produce a flame that looks so much like a wood fire you’ll be able to fool anyone who visits your home.
The drawback: They’re not efficient as a heating source. You need to leave your chimney’s damper partially open to vent the carbon monoxide that the gas fire produces, so much of the heat generated by a vented gas log set goes up the chimney.
Vent-free logs

Vent-free logs are an efficient heat source because you can operate them with the chimney flue closed—so the heat they generate stays in the room. 

That “positive” creates a downside, though: Because they operate without a vent, the logs don’t light up with a tall, roaring, realistic fire like the vented logs do.
Vent-free heaters add moisture to the air, so it's important to install them in a room with proper ventilation to avoid formation of mildew. Few in Arizona report problems with this because the climate is so dry.
You may not use vent-free gas logs in bedrooms, bathrooms or recreational vehicles. Place them at least three feet away from furniture, drapes and other flammable objects.
Some do report the smell of burning kerosene coming from their vent-free logs. If you have a sensitive nose, this style of logs might not be for you.
Rosie loves the look of a natural wood fire when it’s raging safely in a fireplace. So he recommends vented gas log sets with multiple burners that can produce a fire that looks like the real thing.