Install a Direct Current Indoor Fan Motor

Installation of a DC motor in HVAC for Energy Efficiency does reduce watts and increase system SEER.

Do this as a retrofit option on an existing system.

Here are at least two of the motors out that we have installed:

Fieldpiece Concept 3 LER. You can see this motor for sale at Amazon. This motor is good for smaller HVAC units that are not packaged all in one units. It only comes in 1/2 hp. The airflow maxes out at 1400 cfm and you would not want to run it at that high of CFM. That makes this motor good for only a small range of systems for airflows up to 1200 cfm or so. The wiring is simple but does not wire in like a regular fan motor, so it will take a little skill with instructions and schematics. The motor speeds are basically controlled by the thermostat. For dry climates this motor has a built in extended run time relay that helps save on AC costs. It does also have a torque adjustment screw. This is nice because you can manually set the airflow with it – but be careful to install it where you can access the adjustment screw. Also the motor is not reversable – so if the blower wheel does not go the direction you need it to – then you would need to get a new blower wheel. A benefit to this motor is that if you want the fan only to run it will run at 50% speed, and this is nice for air circulation without burning up watts.


Emmerson EcoTech®. This motor is easy enough to find online or at local suppliers. This motor costs a little more. This motor has several different models. I has 3 sizes 1/2, 3/4, and 1 hp. You essentially would install the same horsepower that would be taken out of any existing unit. It also has options for 110v or 220v – so pay attention to what is needed before you buy. Having these options means that you will likely find a motor that can actually works for your installation. It does have 4 speed taps and wires in like a typical motor that comes out. It also has a reversing function if you need it to turn an opposite direction. The drawback to this motor is that if you want a slow speed just for the fan to run – you will have to pull out your inner genius and wire in some relays to get it to power on the slowest speed tap, when the thermostat is only telling the fan to run. It is not easy to figure this out, unless you have done it before.

Genteq EverGreen. This one is for sale at Amazon as well. We do not have experience with this motor yet. This motor looks good, and I believe I studied this motor out few years ago and has a wiring system similar to the Fieldpiece Concept 3, where the speeds are controlled by the thermostat.

[If anyone has experience with this motor or other DC motors please comment and contact me so that I can add to this post]


One thing to be real careful about with these motors is the brackets that hold them in place. Some manufacturures of existing equipment like to use special mounts for motors. In a lot of cases you will need special retrofit mounts that are available. Fasco Belly Band is one and there are other mounts available at suppliers. In some cases even these mounts are not compatible with some blower units. There is nothing worse than going through the motions and then finding out that it cant be done in the end. In some cases you may not be able to find a bracket that works for some particular systems. 

Remember that just dropping in one of these motors does not guarantee that you will get energy savings.  Please review this post first: .. Cutting Fan Watts in Half.






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Posted on April 13, 2012, in Training. Bookmark the permalink. 1 Comment.

  1. I installed the evergreen motor when I looked into it I found I needed a 1hp to replace a 1/2hp due to 4 tons of AC.The belly bend was neeeded.

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