Q. I have a built-in, direct-vent propane fireplace in my living room. The unit was installed nine years ago, and almost immediately, we experienced soot buildup on the glass screen and around the ...

A typical vented gas fireplace can be fueled by either natural gas or propane (some models run dual fuel) with two vents that run to the outside of your home.

Gas fireplaces, including inserts, can be direct-vent or ventless. Direct-vent systems are usually more expensive and less energy-efficient since heat escapes up the chimney.

Vented gas stoves are more popular because they produce more heat than the ventless stoves. Not only that, vented stoves have larger flames so they look more like authentic stoves or fireplaces.

In most cases, a wood-burning fireplace can be converted to gas. With propane, there are direct and vent-free units. Direct-vent gas fireplaces offer the authenticity of wood-burning fireplaces.

We can smell the odor around the stairwell and an intake vent. We had a ventless propane fireplace put in two to three years ago. Does propane have the smell I have described ?