Increase wood fireplace efficiency
I almost passed on this question, but couldn't resist. 

I have been involved in a lot of home energy audits lately. Having spent a lot of time with some very qualified experts, i've learned a lot. 

The one thing about a conventional fireplace is that they are for looks only. Even if the wood is free, it is costing you heating costs every time you light it. The real story is that for the chimney to draft properly and not fill the house with smoke, it has to pull tons, yes really tons, of air from the house to feed the flue. Only about 40% of the heat generated by the burning wood is actually sent into the house. The majority is sent up the chimney, as flue temps can reach 600 to 700. In order for this hot air to escape, it pulls the warm heated air from your home. So in essence, you are trading 40% efficient heat for the paid for heat at maybe 80% to 90%, depending on your heating system. Not a good trade, huh?

My advice is not waste your money on gimmicky promises of high efficiency gadgets. Just enjoy the fire as a romantic mood setting with a glass of wine, but don't forget to close the damper as soon as the fire is out to save your heating bills!