The laws of physics tell us that if you move air over a hot surface you will increase the heat transfer efficiency from that surface.
Many stoves and fireplaces come equipped with fans specifically for that purpose. Others provide air convection chambers so fans can be added as an option. Still others have no capacity for fans.
For some the debate for and against fans on stoves and fireplaces is a point of contention with arguments favoring both sides. Here is our take:
For products with integrated fan designs there’s evidence that efficiency is increased when the fan is in use. This increase while it is real, may be hard to measure in terms of how it feels.
Stoves and fireplaces heat in two ways radiant & convective. If a product is designed primarily as a radiant heater, then the presence of a fan often makes little difference in the amount of warmth you experience. If the product is designed as a convective heater, then the fan is apt to be more significant.
Keep in mind, most of our stoves and fireplaces are meant to work even when the power is out. When this happens of course the fan will not function. While there may be some drop in efficiency it is rarely significant and the stove or fireplace will continue to provide warmth.
Products designed for radiant heating will have very little if any benefit from the addition of a fan. Where they have been tested, the efficiency difference is approximately 2% – 3%.
The electrical requirement for fans means additional installation cost if power is not already present in that location. This is especially critical when inserts are installed in existing fireplaces. Another issue is fan noise. While fan technology has improved, there is going to be a certain amount of noise when they are in operation. Controls enable us to lower their operating level and their output, but if the room is quiet you are likely to hear it. Most of the fans utilized on fireplaces are capable of moving a maximum of 100 to 150 CFM. This means you will certainly feel the warm air when you are within 2 or 3 feet of the fireplace. However, this is typically not enough air movement to move heat from one room to another. Natural air currents in the house will be responsible for that.
If the fireplace you like and select has an integrated fan – don’t think twice. It will be great and with or without power the fireplace will still heat. If the fan is optional on the product you select then consider the expense of adding the fan relative to the benefit. If it is a high-efficiency fireplace or insert then the fan is not likely to make a big difference.