High Efficiency Fireplace Inserts
When heat is the goal, efficiency is key
A fireplace insert is essentially either a woodstove or a gas fireplace that is designed to be installed in an existing fireplace enclosure, usually requiring a masonry fireplace due to safety issues regarding proximity combustible materials. These inserts typically require that a stainless steel chimney liner be placed inside of the existing stone or brick chimney to provide temperature-resistant and easily cleaned ventilation for the insert.
Most fireplace inserts are at least 80% efficient, with some approaching 99%. It is important to note that at the highest efficiencies, so much heat stays inside the house that the temperature of the exhaust gases are low enough for water to condense out, causing problems with traditional ventilation systems. As a result, high efficiency fireplace inserts typically come with their own ventilation requirements, whether they are fuelled by wood or natural gas. Unlike furnaces, there is no specific percentage efficiency which manufacturers are required to maintain in order to claim the term "high efficiency" for a fireplace or fireplace insert. As a matter of course, however, any fireplace or woodstove with efficiency greater than 70% is considered "high efficiency".
As a practical matter, ventless natural gas fireplace inserts are among the most efficient options available for the simple reason that they do not exhaust any air, so no heat escapes. All of the heat that is generated by the fireplace remains in the room where it is located. The only disadvantage to these devices is that any hazardous emissions (such as Carbon Monoxide) would also remain in the room. As such, it is important to properly size the fireplace, ensure adequate ventilation, and install the necessary safety and monitoring equipment if you plan to make use of these technologies.
If you are only concerned with enhancing the aesthetic charm of the room in which you have a fireplace, any fireplace insert which meets local emissions regulations will do the trick – the increased price tag of a high efficiency unit likely won't be worth your while. But if you are interested in purchasing an economical supplementary heating system for your home and you already have a traditional wood-burning masonry fireplace, a high efficiency fireplace insert will be an excellent option for you. If you enjoy a wood fire, then a wood-burning insert will allow you to continue to use your fireplace essentially the same way that you always have while offering reduced fuel bills (in terms of wood burned) and lower emissions. If convenience is the major goal, a natural gas fireplace offers greater ease of use and faster startup and shutdown times than a wood fireplace.