I’ve heard you say many times that using an attic fan is just sucking your cooled air right out of the house and that it’s better just to rely on the soffit and ridge vents. My question is this: is that still true if you ONLY have soffit vents? We don’t have ridge vents and my husband reminds me how we fight with the extreme heat on our second floor. Also, is it still better to shut off the attic fan with just the soffit vents providing ventilation and just count on the A/C now? Or do you have another suggestion?
You are correct that using an attic fan is generally a lousy way to cool your attic when you have a central air conditioning system. And, you are also correct that the reason is that is will not only suck hot attic air out, but also the air conditioned air from inside your house. Passive ridge and soffit venting is a better idea. For the most effective ventilation, I recommend continuous soffit and ridge vents. Air will enter the attic at the soffit, run up under the roof sheathing when it carts heat away in summer and moisture away in winter, and exit at the ridge. This 24/7 ventilation solution is far more effective than any other type of mechanical or passive ventilation solution.
However, to answer your question, having ONLY a ridge vent will not work. To have an effective system, air must be able to enter at the soffit, travel up under the roof sheathing (removing heat in the summer and moisture in the winter) and exit at the ridge vent. If you only have soffit vents, it won’t work.
Once you have a properly functioning soffit and ridge vent system, you can shut down the attic fan for good!