Entire-house followers and attic followers: Two totally different approaches to cooling
QQ Tim, what can you tell me about whole house fans and attic fans? Are they really working on cooling an attic? Not sure which one to consider as I have air conditioning. What does it take for you to work with maximum efficiency? – Robert T., Rockdale, Illinois
A. I’ve installed some whole house and attic fans and seen how effective they can be. Whole house fans are usually located in a second floor ceiling in a house.
A whole house fan is designed to suck in air through open windows and doors and let that air out into nature through an attic. Some can move nearly 300,000 cubic feet of air through your home per hour.
The fans can move so much air that when the windows are open in just one room, papers can be blown off the tables. You can imagine how it would cool you down with so much air flowing over your body. If you run air conditioning, you don’t want a whole house fan to blow that chilled air into your attic.
These fans were the cooling method of choice before modern air conditioners became widespread and affordable. They work well in climates with lower humidity, as the nighttime temperature can drop so much that you 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 normal-sized man may only move 72,000 CFH of air through an attic. You can get 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 loft 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.
The moving air tries to cool the entire attic of the wood because without the fan the temperature of the entire roof assembly and the attic wood can rise to 160 F or more. Think of your entire roof assembly as a huge glowing ember trying to roast you like a marshmallow over a campfire.
In order for both fans to work well, they need large exhaust openings in the roof so that the moving air can escape. Whole house fans need to open windows and doors, and attic fans need many soffit openings to draw cooler outside air into the hot attic. 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.
I have fan tips and videos for the whole house and attic at http://go.askthebuilder.com/fans
QQ Look for quick advice on patching asphalt. Does the cold asphalt really work in bags? I have time and energy, but not a lot of money. – Susie P., Riverside, California
A. The good news is that 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 doesn’t usually contain a lot of sand.
If you want to be successful with the asphalt sold in home centers and hardware stores, first read the directions on the label. 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 patch 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 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 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.
Please visit my website http://go.askthebuilder.com/ blacktop for detailed step-by-step tips and videos of tips on how to patch Blacktop
Tim Carter can call you for free to solve your problem. Go to his website and fill out the form on this page: www.askthebuilder.com/ask-tim/.