It appears that gas fireplace inserts are common in a direct vent configuration (where combustion air is brought in from the outside).
Are there wood burning fireplaces that are direct vent? I'm not finding any with my web searches. Do they exist under a different term? Or do they not exist and, if not, why is that?
Depends on how you are defining direct vent. The usual definition is the gas combustion products are vented directly through the wall and no conventional flue or chimney is required. They also draw combustion air from outside, and the combustion chamber can be sealed off from the house entirely.
You will not find a wood burning fireplace that does not require a chimney. Such a contrivance would not draw properly and would be dangerous for burning solid wood fuel. There are a few pellet stoves listed for this configuration however, but not for logs.
If your main concern, as you mention, is only that combustion air be drawn from outside, there are many fireplaces that offer this configuration as an option, including the ability to seal off the combustion chamber. They typically do this by inserting some device that blocks the device's usual combustion air intake from the house and instead provides a 4" dia. duct connection. It's up to the installer to route the duct to the outside. These all still will require a chimney terminating above the roof, typically 6" dia.
I would start searching for such devices by searching wood burning fireplace outside air. You should find many fireplaces have this option, though sometimes you need to dig in the fine print to see that it's available.
Yes, they certainly do, but require drilling a hole or running a pipe up the flue. There are also no vent logsets that work great. Just close the damper and feel the heat. The non-vented logsets are a great way to use an existing wood fireplace with a new hight tech much more efficient and cleaner fire.
I have installed quite a few wood stoves that had options to directly bring in fresh air to the stove. In some cases I have been able to use the ash clean out for the source of fresh air on fireplaces that did not have an ash clean out I have opened a hole and lined with duct work. These are the main types of venting I preferr, there have been a few that I added a vent through the wall but this allows cold air into the house. I have never run an air supply line up the flue and was thinking if it was done this way would the draft have problems as the stack heated up and now the supply air is getting heated would this cause draft problems?
