The heat from car engines just returned to the garage is bad enough, but when your garage doubles as a hobby or work area, the added heat summer brings can make working in it unbearable. The amount of work you spend on cooling down your garage marks the difference between a somewhat cooler garage and a comfortable working space.
The Cross Breeze
Create a cross breeze in a garage with a window on one wall and the garage door. Open up the window that doesn't face the sun and is in line with the breeze. Adjust the garage door so it is open at least a foot on the bottom. This helps draw in the cooler air close to the bottom and take the warmer air out the open window. Since hot air rises, an attic vent can also remove some of the garage's heat during the summer.
An exhaust garage or attic fan placed in the drywall ceiling of the garage with side vents in the garage roof gables and a slightly open garage door or window can suck all the heat from the garage. Exhaust fans, when used indoors, are called whole-house fans. They are relatively quick to install and come with a switch you can place on a wall. If you open the garage door too much, the exhaust fan loses effectiveness and, as the day heats up, it brings hotter air into the garage.
Nothing Like Insulation
With insulation, you have a solution that benefits you during both summer and winter. Adding insulation between the rafters of the garage's ceiling and inside its walls if it is unfinished significantly can affect the garage's indoor temperatures. Insulation creates a buffer zone that impedes thermal flow through it, rated by its R-value, or its resistance to thermal loss. When installing fiberglass insulation, choose the batts that fit between the studs and are sized to the stud's width.
Garage doors act like solar blankets, heating up when pelted by the hot summer sun or cooling down when doused with winter's wet weather. An insulation package made for garage doors – available at most home improvement and hardware stores – can affect the comfort factor inside the garage. These aftermarket products are quick to install.
Plant a Tree
Nothing works quite as well as nature at cooling down a hot garage. A large deciduous tree -- one that loses its leaves in the winter -- provides ample shade when placed between the garage and the afternoon sun. Fast-growing leaf-shedding trees include the hybrid poplar, weeping willow and silver maple. Check your region's hardiness zones before planting a tree and set it back far enough from the house so that its roots won't interfere with foundations or underground plumbing lines.