Q: I know that a standard open wood fireplace is not an efficient way to generate heat for my home. What can I do to make it more efficient?
A: There are a number of improvements that you an make to an open wood burning fireplace that will improve its efficiency. Lets talk first about the ways a person can make their fireplace more efficient while it is not working and dormant. They vary widely in cost and effectiveness so i will list them in order of cost.
1) Chimney Balloon
If you use your fireplace at all it is likely that your damper is not in prime condition. The US Department of Energy says that on average 15% of a homes heat loss is through the fireplace damper. They are made of metal and they are heated and cooled regularly so they tend to warp and corrode over time. Unfortunately, they are tucked up out of sight inside our chimneys so they are not regularly inspected and they are dirty to deal with. I have been very impressed with a product called a Chimney Balloon that is a fireplace damper insulator. It acts like a draft stopper for your fireplace damper and plugs the flue and damper area air tight so no heat escapes and no cold enters. It works particulary well in chimneys that have no damper and can allow the homeowner to save 30% on their heating bill when used in this type of application. They can be found at www.chimneyballon.us
Cost $40-$50 for standard sizes.
100% efficient in saving heat while fire is not going.
2) Tight fitting glass fireplace doors
Installing tight fitting fireplace doors can help you control the amount of inside air your fireplace has access to while it is burning and while it is dormant. Installation of a custom sized fireplace door is reasonably easy for a Do-it-Yourself minded person with some familiarity with hand tools. Glass doors restrict the air flow to the fire during the burn by drawing air only from the bottom of the hearth (since heat rises therefore air at the floor level is always the coldest.) in order to use cooler inside air for the combustion process. Glass doors can also help control the smoke from a fireplace. It tends to force the smoke up the chimney. Unfortunately, using glass doors actually reduces the amount of radiant heat your fireplace can cast into the home. This can be counteracted by using a heatilator. They can be purchased through online distributors like www.northlineexpress.com
Cost: $350-$600 for a good quality set.
Only around 60% efficient if used without a damper in a dormant fireplace
3) Chimney Top Dampers
There are some great chimney top dampers on the market most of which are made by Lymance. This is a particularly usefully product if you have no damper on your fireplace at all. This damper is installed on the top your your chimney like a cap and it has a spring loaded closure system that allows you to close the cap when you are not using the fireplace. This helps to prevent the massive heat loss caused by a chimney that is always open.
However, There is one known negative issue to this solution. Since you are closing your chimney from the top you are still allowing much home heat to rise and fill the chimney. This air eventually cools and sinks and can create a slight cold draft sensation at the hearth. Furthermore, it can make your fireplace give off a foul odor since the fumes from the deposits in the chimney are not allowed to exit the chimney. After years of regular use a locktop damper can warp [Since it is made of metal] and become less efficient. This usually takes longer to happen than a standard damper though since it is further from the heat source.
Many locktop users have informed our helpline that they bought a fireplace plug draft stopper like the Chimney Balloon to close the flue down low by the damper as well, in order to stop this cold air convection process and stop the draft sensation and odors.
Cost: $500-$800 installed
100% efficient at first but decreases after a few years of heavy use.