i usually tell my customers it's a personal prefrence. The downside to having the fan run all the time is it dosen't allow all the water to run off of the coil in the cooling mode. When this happens it gives the house a more humid feeling...esp. if you live in a humid environment and that's what it's trying to do anyway is get rid of the humidity.
Personally i have mine on an intermitent setting where it'll cycle off for a short period and then the fan will come back on. whether or not the system is calling.
How you use the system is for you to decide. As to the pros and cons, there are a few considerations. For example:
During the cooling season, at the end of a cooling cycle the fan should turn off for about 2-3 minutes, then restart. The 'off' cycle is to allow water condensed on the indoor coil to run off the coil and out the system drain. That keeps evaporation of that water to a minimum, thus enhancing the dehumidification process. If you elect to have the fan continue to operate absent a cooling call, you'll likely be comfortable at a slightly higher temperature setting due to the movement of air in the rooms aiding in evaporation of moisture from your skin. If you elect to have the blower off absent a cooling call, when sitting still your body may warm the air surrounding it, thus making you feel warmer than the room temperature. For that reason, continuous fan operation is a plus in the cooing season.
If you use the same system for heating, you may prefer to have the blower cycle 'off' absent a call for heating.
But if you have IAQ products installed, their operation is improved substantially when the blower is turning slowly, as it does with the Infinity variable speed products.
So depending on the season, depending on the system components and depending on your personal preferences, it's all very clear and simple, right?
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