I suspect that's the case. Less work being done means less power consumption. But @MisterBill2 said

If it is the typical Radial 'squirrel cage' looking fan then it should reduce current when progressively blocked off.
Same as the typical vacuum cleaner etc when you block the suction (Radial fan). the current goes down drastically.
Most radial and axial fans have this effect.
Modern HVAC systems typically use a ECM (electronically commutated motor) , these are 3phase motors with the commutation electronics internal.

 

Judging from the age of the neighborhood and the looks of the small unit - I'd say it's probably a 1960's model. Probably the basic operating system, the fire box gets hot, triggers a switch that turns the blower on. Fire box cools, switch opens and the blower shuts off. IF it's a multi-speed fan then it's likely dependent upon which wire is connected. With Heat and AC, they sometimes utilize a different speed, one for heat and another for AC. These Utah homes didn't come with AC back then. If you have it either you've upgraded or bought a newer home recently built during the land boom. Every farmer's heir is selling property to make quick big bucks and developers are building those cheap cookie cutter homes. The look real nice, but they don't last like the old brick & mortar homes. However, they're probably stronger in earthquakes. We had one here last year and I was in the basement when it hit. I don't recall how many steps it took me to get up stairs, but I'm betting it was around six steps, all the while exclaiming SHIIII - - - (you guessed it), over and over until the shaking stopped.

I grew up in Los Angeles. Earthquakes, scary as they are never shook me up like this minor quake did. But then this is the first brick home I've ever lived in. Knowing how unsound they can be during earthquakes, I was afraid of a collapse. Here's the home security video:

https://www.cnn.com/2020/03/18/us/utah-earthquake/index.html
I'm about 35 miles north of that area. Shaking here wasn't that bad, but still scared me out of the crap.

OK, I watched the video. I have had the ground jumping under my feet, but it was because others were making "very loud noises" a few hundred feet away. And it was in an area with ground not as solid. Not pleasant at all.

 

On all Centrifugal type Pumps or Blowers,
the Load is directly affected by the Volume of moved medium,
and is roughly inversely-proportional to the Pressure or Vacuum created.

These trends are not affected by the type of Motor used.

AC-Blowers have "Forward-Curved" Blades, ( as opposed to "Backward-Curved" Blades ),
Forward-Curved-Blades favor high-volume, low-pressure-differential, applications.
Backward-Curved-Blades favor lower-volume, higher-pressure, applications.
Backward-Curved-Blades usually produce less noise.

It would be an interesting experiment to flip the Squirrel-Cage so that
it's Blades are facing "backward", instead of "forward".
This "may" result in quieter operation,
and will definitely provide greater suction for handling clogged, or under-sized, Filters.
.
.
.

 

On all Centrifugal type Pumps or Blowers,
the Load is directly affected by the Volume of moved medium,
and is roughly inversely-proportional to the Pressure or Vacuum created.

These trends are not affected by the type of Motor used.

AC-Blowers have "Forward-Curved" Blades, ( as opposed to "Backward-Curved" Blades ),
Forward-Curved-Blades favor high-volume, low-pressure-differential, applications.
Backward-Curved-Blades favor lower-volume, higher-pressure, applications.
Backward-Curved-Blades usually produce less noise.

It would be an interesting experiment to flip the Squirrel-Cage so that
it's Blades are facing "backward", instead of "forward".
This "may" result in quieter operation,
and will definitely provide greater suction for handling clogged, or under-sized, Filters.
.
.
.

Reversing the blower wheel would be far more bother than it was worth. I had to replace my blower motor a few years back and I know.

 

Backward-Curved-Blades usually produce less noise.

It would be an interesting experiment to flip the Squirrel-Cage so that
it's Blades are facing "backward", instead of "forward".
This "may" result in quieter operation,
and will definitely provide greater suction for handling clogged, or under-sized, Filters.

Wish you would have told me this before below:

 

It would be an interesting experiment to flip the Squirrel-Cage

Well, the results are in. Having swapped the squirrel cage around (blades facing backwards) the fan is a lot quieter. However I also notice a lower volume of air being moved. When blocking with my hands, the air doesn't seem to resist any more than when around the other way.

Another thing about this rig - someone replaced the factory original motor. This motor is the same size as far as shaft and mounting hardware, but it's far bigger than what was originally in place.

And this is the way it's going to stay. I'm not pulling it down again and disassembling the motor and cage just to reverse the cage back to OEM. It's moving less air but it's moving enough air. When on High the fan seems to hum. Didn't notice it before, maybe because of all the noise. Hums also on Medium. On Low if it's humming I can't hear it. And again, the air movement is satisfactory.

Thanks for the suggestion. Only, it didn't result in higher pressure; just lower air and noise. But that was something I was after when considering some kind of fan speed moderation. This works. And I'm happy. Thanks.

Thanks ALL. And hope your 2022 is better than the last few years have been - FOR SURE! Happy New Year All.

 

Well, the results are in. Having swapped the squirrel cage around (blades facing backwards) the fan is a lot quieter. However I also notice a lower volume of air being moved. When blocking with my hands, the air doesn't seem to resist any more than when around the other way.

Another thing about this rig - someone replaced the factory original motor. This motor is the same size as far as shaft and mounting hardware, but it's far bigger than what was originally in place.

And this is the way it's going to stay. I'm not pulling it down again and disassembling the motor and cage just to reverse the cage back to OEM. It's moving less air but it's moving enough air. When on High the fan seems to hum. Didn't notice it before, maybe because of all the noise. Hums also on Medium. On Low if it's humming I can't hear it. And again, the air movement is satisfactory.

Thanks for the suggestion. Only, it didn't result in higher pressure; just lower air and noise. But that was something I was after when considering some kind of fan speed moderation. This works. And I'm happy. Thanks.

Thanks ALL. And hope your 2022 is better than the last few years have been - FOR SURE! Happy New Year All.

And I am thinking that it was quite a bit of work, like I guessed it would be. I am glad it produced the results that you wanted.

 

Thanks Bill. Yes, it was a bit of work. Had some difficulty getting the cage off the motor shaft. Once I had it off I used some fine sand paper to clean the shaft and the blade went back on no problem. But I had to pull the box down and take the face (blower assembly) out. Then I had to take the blower off the face. Once the blower was liberated I had to take out the choke plate and slip the cage off the motor shaft and swap it around. Then I had to put it all back together again. I'm on the fence as to whether it was worth while, but I have to think it was. I still get satisfactory air flow AND I don't have to deal with all the noise. So in the end - yes - I'm happy about it.