Ask the Builder: Whole-house, attic fans all about air movement – Entertainment & Life – The Columbus Dispatch
Q: What can you tell about whole house fans and attic fans? Are they really working on cooling an attic? If a person has air conditioning, should they consider a fan? What is required for them to work with maximum efficiency?
A: I can give a lot of advice to whole house and attic fans. I’ve installed a few of each and seen how effective they can be. Whole house fans are usually located in a second floor ceiling in a house.
A house-wide fan is used to draw air in through open windows and doors and vent that air through an outdoor attic. Some can move nearly 300,000 cubic feet of air per hour (CFH) through your home.
The fans can move so much air that when the windows are open in just one room, papers can be blown off the tables. When an air conditioner is running, you don’t want a whole house fan to blow the chilled air into your attic.
These fans were the cooling method of choice before modern air conditioning became widespread and affordable. They work well in climates with lower humidity, as the nighttime temperature can drop so much that you will need a blanket to sleep in.
Attic fans are very different. They are installed on a roof or through an external wall in an attic. A full-size fan may only move 72,000 CFH of air through an attic. You can get larger ones that move up to 360,000 CFH of air, but these are usually designed for wall mounting.
The roof fans simply pull air through a hot attic space to reduce the infrared heat gain you feel through the ceiling of your home. If you want your home air conditioner to cool you down better, you might want a roof fan or two.
In order for both fans to work well, they need large ventilation openings in the roof so that the moving air can escape. Whole house fans need windows and doors open, and loft fans need lots of soffit openings to draw cooler outside air into the hot loft. Without this open space, the fans won’t move a lot of air. It’s easy to install waterproof gable end or pot vents in the roof to allow air to get back outside.
Q: What’s the best way to patch asphalt? Does the cold asphalt really work in bags?
A: The asphalt material sold in bags and buckets really works. It doesn’t create the same silky smooth surface as hot asphalt because the cold material usually doesn’t have a lot of sand in it.
If you want to be successful with the asphalt sold in home centers and hardware stores, read the directions on the label first. Too many people skip this important step.
I’ve got the best results by chiseling the edges of the potholes that I’m filling with a cold chisel and 4 pound hammer. I want the edges of the plaster to be at least 1 inch deep and I do my best to tilt the chisel so that the bottom of the hole is wider than the top. This is how dentists keep a filling in your tooth.
It is very important to remove any loose material from the bottom of the pothole. When you have crushed stone with fine particles, put something in the hole and compact it well. Blow all of the dust out of the hole and brush the edges of the hole so the asphalt adheres well to the sides of the existing asphalt.
Tim Carter writes for the Tribune Content Agency. You can visit his website at www.askthebuilder.com to see examples of the projects mentioned.