Your question is still rather unclear. However, I assume you are you interested in whether you should use, from a power consumption point of view, your printer's wifi or the wired ethernet.
To be sure you should measure it with a power meter, but I think it won't make much of a difference, as I would be surprised if the printer is optimized towards this. Stating the make and model would also help. Also, you should check if you can disable the wifi on your printer. If you can't then it's even more likely that it won't make a difference.
IMO, if you're interested in saving power (good!), just turn off the printer when you don't use it (which seems to be often as you say it's "only used seldom"). As a bonus: walking to and reaching out to turn on the printer is a good exercise as well.