Direct Vent -aka vented gas fireplace, sealed gas fireplace, solid glass fireplace Pros - - much more efficient than traditional open fireplaces - Sealed to prevent exhaust fumes from entering the home - Doesn't require a chimney to be built outside, above the roof - Doesn't use or lose air from inside the house - Many designs available - Contributes to Energy star rating for your home - More realistic flames and logs Cons - - Sealed fireplace doesn't have that "open hearth" feel - More expensive than non-vented appliances - Logs and burners are non-interchangable Average cost to install - $4500
Vent Free - aka ventless or non-vented Pros - - 99.99% efficient - Instant heat - Can be installed nearly anywhere - No venting or holes in the house needed - Can change logs and burners for upgraded look or performance as technology advances Cons - - Releases a quart of water per hour into the air inside the home; can promote mold in lower levels and well-sealed homes - Reduced overall indoor air quality; you're literally burning the air in the house and returning it back inside the house - Often associated with a smell; NOT recommended for bedrooms or for people with breathing issues (asthma, COPD, etc.) - Flames and logs are often less realistic than their vented counterparts