by Shana Fong on August 18, 2010
Here’s a piece written by Matt Golden and Jess Chamberlain for Sunset Magazine on best practices for keeping your house cool, the environmentally friendly way.
To keep a house cool, it’s really about either:
- Keeping the sun out, or
- Keeping the air cool/conditioned
In a retrofit situation, you have to first assess what your possibilities are:
- Is there an attic we can insulate?
- Are there eaves that are blocking some of the summer sun?
- Is there an existing cooling system?
This really affects what the best approach to take is.
For an average house in a cooling climate with an attic, we’d recommend reducing the cooling load as much as possible and utilizing passive cooling:
1. Air sealing
2. Adequate attic insulation (min. R-38) to create a thermal barrier
3. Radiant barrier, if there are ducts in attic; on roof decking or in attic
4. Low-E glazing on windows
5. Whole-house fan
This route is very cost-effective from a long-term standpoint; i.e. you’re not paying to condition the air, you just pay for the equipment and installation.
The other option is to actively cool the house, in which case you’d invest in the fundamentals (such as air sealing and insulation), then install a high SEER-rated AC unit (min. 16-18 SEER rating) designed to ACCA’s manuals J, S, D & T. If air handling equipment is located in the attic we would recommend encapsulating the attic with air-impermeable spray foam and bringing the attic into the building envelope. This prevents hot attic air (150˚F+) from infiltrating the duct system.
Easy Cooling Tips:
- Keep your AC unit in the shade
- Keep the coils clean
- Install high efficiency lighting (it keeps house cooler)
- Turn plug loads off
- Stop the sun before it gets into your house – use external shading, overhangs, and deciduous trees
- Low-E coating on windows
by Shana Fong on July 19, 2010
The gaps you can find around the windows and doors of the average American house add up to the equivalent of a hole in the wall that measures 10 inches by 10 inches.
Your house has more leaks than the CIA. There are cracks all over the place. Your doors and windows don’t quite meet their frames; there are tiny spaces where the walls almost join the floor; there are open areas around your electrical and plumbing outlets. And these little gaps eat energy. In fact, an amazing amount of heat in the winter – or cool air in the summer – escapes through them. But you have two simple weapons to fight with: caulking and weatherstripping.
Energy Facts
- Caulking and weatherstripping an electrically heated home can keep some 1,000 pounds of CO2 out of the air. So if 1,000 of these homes were weatherized, over a million pounds of CO2 would be saved.
- Believe it or not, stopping air infiltration can reduce your home’s heating and cooling bills by up to 40%.
- People are concerned that although weatherstripping may save energy, it will keep fresh air out of their homes. While it’s true that some ventilation is necessary, it’s really not much of a problem – a typical house may get twice as much fresh air as it needs. In other words, the air is probably flying out of your house as quickly as you’re heating or cooling it.
Caulking vs. Weatherstripping
- Cracks without any moving parts – like the places where a wall in your house meets the outside edge of a window frame, or two other dissimilar materials come together – can be sealed with caulk.
- The places where doors and windows close into their frames can be sealed with weatherstripping – cleverly designed strips of felt, rubber, metal, or plastic that fill the spaces around doors and windows, and compress when you shut them.
- Weatherstripping materials come in many styles. Some are self-sticking, so you don’t even need a hammer to install them. Others must be nailed on. Still others are crafted so pieces on the frame and the door lock together when the door closes.
- One of the trickiest places to weatherstrip is where the door meets the threshold. Special “shoes” and “sweeps” are available to stop these air leaks.
- Besides saving energy, weatherstripping and caulking have an additional benefit: By stopping drafts, they’ll make your home more comfortable.
Leak Patrol
- Some evening, when your house is at least 20°F warmer than the outdoors, hold your hand up to various places around windows and door frames. If you feel any drafts, the windows and door frames need weatherstripping.
- You can also use a smoking incense stick to look for drafts. Hold the stick near places you think might have cracks; if the smoke dances or gets sucked in, you’ve found a place to seal.
- Many of the biggest air sealing opportunities are up in the attic and below your floors. For these harder-to-reach leaks, it’s a good idea to call in a trained professional such as Recurve to quickly identify and remedy your home’s major leakage areas.
Excerpted from 30 Simple Energy Things You Can Do To Save The Earth, by The EarthWorks Group.