Not all blower motors are designed for ON mode!
Check if the fan is rated for continuous use. If your fan isn’t rated for continuous use but you still elect to run the fan in ON mode, budget to replace the fan sooner than normal with a fan that is designed for continuous use.
- Filter gets dirty faster, system works harder.
Remember the filter we discussed in Part 1? The filter clogs up more quickly if you run the fan continuously. A clogged filter makes the blower motor work harder and uses more electricity. If you run the fan in the ON mode, change your filter every month.
- Unconditioned air is always in the loop.
If supply ducts are in the attic or crawl space, unconditioned air will circulate into the home all year round, which may cause the system to cool or heat more frequently.
- Humidity increases, moisture is introduced into the house.
During the cooling season in humid climates, running the fan in the ON mode can actually increase humidity inside your home, which introduces moisture into the house.
- Environmental issue
Last but not least, there also is an environmental issue…see Part Tres of Three!