- Vents: Your choices are gable, turbine, powered, or ridge. Most homes now are built with an ridge vent at the top of the roof, but the other vents are still in use. All that matters is that there is sufficient airflow to keep your attic within 20 degrees of the outside air. If it is 70 outside and 90 in your attic, you probably have enough airflow, but if its higher than that, you need to firstly check the intake vents along the underside of your eaves. Blow compressed air in them from the outside to clear any obstructions(usually blow-in insulation). If the vents are clear, you want to add a powered attic fan. You can use the wired kind or the more expensive solar powered versions, either way, 20 degrees is the target. Most powered fans come with a thermostat set to turn on at 90 degrees F. Here's an expert from an HVAC forum.
The rule with attic ventilation is 1 : 300 with a vapor barrier and 1 : 150 without a vapor barrier. So if you had insulation in the attic with a vapor barrier and the attic was 900 sq. ft., you would need 3 sq. ft. of free venting. If it was blown in insulation without a vapor barrier, you would need 6 sq. ft. of free venting. This is when you have an equal amount of square footage of high and low vents ( gable and soffit). Your concern about attic fans is correct. The problem is not the fan but the over sizing of attic fans. Most attics can only handle about 1500 cfm of ventilation because of the vents. Your fan that you have probably moves about 2000 to 5000 cfm. In which case it could cause a problem with drawing air from the home and causing the problems you mentioned. Properly sizing the fans is important because of this. You could increase the size of the vents but you're looking at more than doubling the amount. You're much better off putting in the proper size fan. The volume of air in the attic remains constant. So if the vents only allow 1500 cfm and the fan moves 2500 cfm, it will seek to get the air from somewhere, like the home. If the fan couldn't get the air from anywhere else, you would just burn out the fan.
So do the math, and either install more venting or get an appropriate sized fan.
- Radiant Barrier: EVERY ATTIC NEEDS RADIANT BARRIER!!!!!
Radiant Barrier (attic foil) blocks radiant heat from the sun from infiltrating the interior of the attic space. Radiant Barrier is usually stapled to the underside of the rafters. Radiant heat is bounced off the foil and back through your roof to the outside where you want it. This is the cheapest and most rewarding insulation job you can do if you have a hot house and don't already have radiant barrier insulation. Attic Foil Radiant Barrier provides a great product and is easy on your wallet.Best of all, it doesn't make you itch!
- Insulation: FiberGlass or organic insulation either laid out or blown in is the next layer of defense. Fill or lay in insulation to the level or even higher than the ceiling joists. Buy as much (R-Value) as you can afford. Its a proven investment. But only marginally effective if not combined with radiant barrier.
- Bathroom & Kitchen Fans: Make sure the baffles are working properly so that those vents are not leaking air to and from the attic when they are not in use. Look into replacing with better units.
- Attic Access: If you have an attic door in the interior of your house(not in the garage), Make sure it is insulated. If when closed, it is a different temperature than the rest of the ceiling, you need to insulate it. You can use a commercial product or simply aluminum foil, styrofoam sheets, and duct tape to get the job done.
- Appliances: Appliances generate heat, so make sure you have energy star rated appliances. Make Sure your refrigerator door has a good seal. Hybrid Hot Water Heaters actually take heat from the air and use it to heat your water, so its a win win situation. If your hot water heater is warm to the touch, go get some water heater wrap. If you have a window air conditioner, make sure the window is sealed. The plastic adjustable side panels don't work well at all, use aluminum foil and duct tape to make an air and radiant heat seal. You can then cover with a folded pillow case to make it look like a drape. Works and looks great. Check the space between the bottom window and top window, on some older windows, when the bottom window is open to allow for the air conditioner, there is an air space at the top of the bottom window, if there is, seal it. Consider using your microwave and toaster oven instead of your full size oven and range. Saves energy too.
- Dryer Vent: Add a baffle or better yet 2 baffles 5 to 6 inches apart in the dryer vent close to where it goes outside. This will help prevent outside air from getting into your laundry room via the vent hose.
- Electronics: Turn them off when not in use. They create heat when in standby. Check out these smart powerstrips that turn off other electronics when the main outlet senses the main appliance is off. Electric wall plug timers have been around a while now and are great for lamps and other small electronics you want on a schedule.
- Shades: Invest in some good insulated shades to reflect the heat back out the window. A good shade should be thick and have a white outward face. These Roman Shades work well.
- Weather Stripping: On Windows and ESPECIALLY DOORS!!
You want to stop air from getting in. You can get this anywhere, even walmart.
- Central Air Intake: Make sure you have a clean filter, and replace regularly. Make sure the intake chamber is sealed from the rest of the wall. An unsealed air chamber can pull hot air from the attic down the wall and make the A/C work twice as hard. Make sure there is no furniture on top of the exhaust vents.
- Closets: Check your closet ceiling, is it drywall or is it plank? If you find its plank, seal with drywall or aluminum foil and duct tape.
- Cabinets: Check your cabinet ceilings, is it drywall or is it plank? If you find its plank, seal with drywall or aluminum foil and duct tape.
- Ceiling Fans: Install one in every room that you spent a lot of time in. They make the room feel cooler. You can find them as cheap as $11 when walmart has a sale. Found some for $21 HERE. My Lowes has some for around $25.
- Light Fixtures: Insulate the light fixtures so attic heat is not pouring down through it into your living space. If the metal of the light fixture is warm after the light has been off for hours, it needs to be insulated. A $3 can of "Great Stuff" expanding foam can insulate at least 4 fixtures. Insulate the ceiling fan mounting points too.
- Computers: Decide on a time when a computer should be turned off and set a scheduled shutdown time. Go into Control Panel -> Scheduled tasks and create a task that runs for example at 10pm and issue the command "shutdown /s" to shutdown the computer to save energy and reduce heat.
- Windows: Obviously triple pane is best, BUT that can get expensive. Simply adding storm windows is adding another layer. You get the same R-Value as if you had double or triple pane with an added benefit. If a storm window breaks, its $40 for a WHOLE window, MUCH cheaper than replacing or fixing your standard window. The best color for a window is white.
- Roof: The one thing most people never acknowledge is that the best color for a roof to be is WHITE. If you want to paint (coat) it white with a Hydrated Lime and water mortar, go ahead, for less than $100 you can coat your entire roof. Barring that, choose the BRIGHTEST shade shingle you can stand. DIY examples HERE.
- Walls: AGAIN, WHITE, especially in the south. If you have a brick house and want to go white, consider wrapping the house in standard or preferably aluminized house wrap, then install vinyl siding, the extra layer of insulation will keep the brick from absorbing heat all day long and then dumping it into your house while you try to sleep.
- Crawlspace: Reports have shown that you can seal the whole crawlspace to lower your electric bill, insulate the foundation walls, lay down good moisture barrier and optionally install gas aware vent fans. You then open a small section of ducting so the crawlspace air is conditioned by your heatpump to control moisture. You can also optionally install an automatic sump pump or stand alone dehumidifier.READ THIS
- Central Air: Make sure it is clean and has a full charge of refrigerant. If it is in the sun, you can paint it white. If it is a package unit, it could use more insulation like this. Check to make sure that your outside unit fan is not blowing hot air against the eaves of your house. Air rises in a cone, not a straight column. This heated air can cause your attic to get hotter than it needs to be. It also can cause nearby windows to become hot from the heated air rolling down the wall. To solve the problem, make a cowl out of a material of your choice and direct the air away from your house. Economical high SEER units HERE
- Landscaping: Plant some shade trees. If you plant trees near your house, choose trees that consist on many SMALL trunks, not one LARGE one. Stay away from oaks and pines, if it falls on your house, you won't be happy. Consider white pebble stone instead of black asphalt for your driveway.
- Climate Control: Invest in a programmable Smart Thermostat. It will keep your house comfortable and your electric bill low.
- Lights: Replace your incandescent lights with CFL. Save 60 - 80 watts per light bulb. They also produce that much less heat. LED lights are even better.
- Water: The less you use, the less you have to heat. The more money you save. Look at this and this. I mentioned Hybrid water heaters earlier and wanted to reiterate that Hybrid Hot Water Heaters use 60% LESS energy than standard element heaters. Heat Recovery systems give you hot water using waste heat from your air conditioner/heatpump like THIS one.
DOE Energy Saving
Waste Oil Heater
Drain Heat Recovery
13 Free or Cheap Ways To Keep Your Home Cool This Summer
Advanced Energy - crawspaces.org