This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
In terms of basic human needs, shelter comes in right after food, air, and sleep. Over years of human development, buildings have become some of mankind’s greatest achievements. A look at the skyline of any major city showcases centuries of technological advancements and creativity. Yet, the impacts of buildings on the environment and our resources are rarely at the forefront of the energy policy dialogue.
We tend to focus on the sources of energy like wind turbines or nuclear power plants when discussing our energy sources. At the end use side of the equation, we look to light bulbs and cars. Buildings? They aren't exactly sexy.
Consider this: according to the U.S. Energy Information Administration, our nation’s buildings consume over 40 percent of the energy consumed across all sectors - that is even more energy than consumed by the transportation sector (29 percent). And in our homes and apartments, nearly half (49 percent) of all energy is used for heating and cooling.
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Buildings consume energy in a number of ways: lighting, heating, cooling, appliances, etc. These are all very important, but in light of the record temperatures sweeping the country, we'll start by looking at heating and cooling in homes. The U.S. Department of Energy and Environmental Protection Agencies have put together a handy graphic showing the common areas where a home loses its heating and cooling energy.
Some of the areas are no brainers, like around doors and windows, but some are not as common, like openings in the attic for ductwork, or under your kitchen sink. Also notice that a home loses energy not just by losing cool air to outside, but also taking in cold air during the winter.
Depending on the home, a significant portion of energy used for heating and cooling is wasted. The reason is that over time, a house or apartment settles and develops leaks here and there; insulation is trampled down, and appliances get dirty and become less efficient through normal wear and tear. You can think of a building as a complex machine with a lot of moving parts, and over time, things start to wear out and performance decreases. So just like a car, bicycle, or airplane, a house can use a tune up every now and then to get it performing at its optimum level.
In my own home, I am surprised to see light framing the doors, meaning air has no problem seeping through. The house was remodeled just a few years ago with energy efficient appliances, materials, and weatherstripping, so I had little reason to suspect our home was losing energy. In a cruel turn of events, the hot and dry weather have dried out the clay soil under the house, leaving the foundation to sink and causing the all sorts of openings in our house. You can (literally) see the kilowatt-hours slipping away.
So how do you know if your home needs a tune up? Sometimes it’s obvious (like my house), and sometimes not so much. The first step would be to perform an energy audit - that is, assessing the current condition of your home to see if there are areas where air is leaking in or out of the house, if insulation has been trampled down, or the original air conditioning unit can be swapped out for a modern, more efficient model. The quality and detail of energy audits can very widely. If you’re looking for a quick, non-intrusive first glance at your home’s performance, you can check out online energy audit tools. A quick Google search pulls up Energy Savvy and the Department of Energy’s Home Energy Tool.
For these online tools, you enter information about the characteristics of your home: year it was built, if it has single- or double-paned windows, type and condition of your A/C system and water heater, and so on. These online tools excel at giving you an idea of how your home is performing from the comfort of your computer.
However, having an in-person energy audit will provide the most amount of detail. Typically, an energy auditor will perform a walk through of your home and visually inspect around doors and windows, measure insulation levels in the attic, and ask about any comfort issues or other problems you are experiencing. It’s a good idea to have air infiltration tests like a blower door or duct blaster performed to identify any hard to reach leaks. From my experience, energy auditors have also found things that a computer program can’t, like ventilation ducts that aren’t hooked up to rooms in a house.
While the general public might not think about building efficiency all that much, governments have recognized the impact of buildings and their occupants and have launched programs to encourage energy efficiency. The U.S. Department of Energy and Environmental Protection Agency administer programs like Home Performance with Energy Star and the Better Buildings initiative that encourage whole house energy retrofits. Many state and local governments help low income residents weatherize homes to save money and energy, while utilities are recognizing the cost effectiveness of building efficiency.
By making modest improvements in heating and cooling efficiency, we can relieve stress on electric grids while possibly saving some dinero. Leaky ducts and walls are just the tip of the building efficiency iceberg, though. There is a whole world of light bulbs, appliances, smart homes, water heaters, and more to discuss. In the meantime, stay cool!
