One of your best options for a fairly straightforward conversion will be a product such as the Flame Monaco XTD EPA Zero Clearance Wood Burning Fireplace
. Unlike a traditional open fireplace, this unit is essentially a closed combustion wood burning stove built within a fireplace chassis. This allows the unit to be safely installed into a framed wall cavity. The limited amount of combustion air and recirculating design means that the fireplace utilizes fuel efficiently and burns for long periods. The unit also has the ability to use a heat duct and fan that can duct heat to your HVAC system.