Heating Duct Fans

furnace and heating duct fan locationHeating duct fans are an ideal way to increase the energy efficiency in your home. The operating principle is pretty simple, but they can make a big difference. The blower in your furnace is the primary means by which warm air is pushed through the ductwork and out into your house.

In some cases, though, the airflow has lost a lot of momentum by the time it gets to the vents and doesn’t enter the home with enough force to disperse evenly throughout the home. The result is patchy temperatures. One spot may be quite warm while another area near by is quite a bit cooler.


There are several ways that heating duct fans can be installed. Ideally, they will be built right into your ductwork when it is originally installed. These fans are made to fit perfectly into the factory ductwork and are the quietest and most efficient. The duct fans are hardwired into the furnace switch and only operate when the furnace blower is on. This decreases the amount of electricity that the fan would use by operating a separate thermostat and switch.


In the event that you are trying to retrofit a heating duct fan into your ductwork, then your choices are a little bit different, but they can still work quite well. Certain manufacturers have designed small, quiet, but very powerful fans to sit in a small housing that can be mounted inside of your ductwork very close to the vent. Not only do these fans push a greater volume of air out of the vent, they also draw more air up through the ductwork at a greater speed.

It can be difficult to wire these fans if you don’t have any electrical experience. The best way to do it is to fish a power source right up through the vent, but you may need to get a licensed electrician to help you connect that power source into your breaker or fuse box. There is a saying when it comes to working with electricity. Better safe than dead. Get some help if you’re not sure what you are doing.

Shopping Tips

When shopping for heating duct fans there are a few details that you want to watch for. The first piece of information that you need to acquire is the CFM rating of the fan. CFM stands for cubic feet per minute. This is a measurement of how much air the fan moves per minute. As you are shopping, check the CFM rating on different models so that you get a good idea of what the norm is for the type of fan that you are looking at.

You will also want to check the noise rating of the fans. Some fans work very well at moving air, but are pretty annoying when they are on. The noise and vibration that they produce make it seem like the increased airflow is hardly worth it. Each fan should be rated for noise. Make sure that you choose a quiet one. Even if it is a little more expensive, in the end you will be glad that you spent the extra dollars.

photo by Justin Baeder -CreativeCommons attribution