Heating and cooling are two of the biggest energy expenses that most consumers face. But hot air always rises, for free! The sun’s energy can be harnessed for heating and cooling that can save energy and money in homes and offices. While passive heating is familiar to many, few understand how passive cooling works in hot climates. This natural, energy conserving approach to cooling our structures can help us reduce use of fossil fuel driven air conditioners, while saving money. Join us to find out how you can put passive cooling to work.
Read the transcript below.
Welcome to Good Dirt Radio….reporting on positive solutions, taking root.
Heating and cooling are two of the biggest energy expenses that most consumers face. But hot air always rises, creating convection, which can be harnessed for heating and cooling in ways that can save energy in homes and offices. While passive heating is familiar to many, few understand how passive cooling works in hot climates This natural, energy conserving approach to cooling our structures can help us reduce use of fossil fuel driven air conditioners, while saving money.
Jim Hallock, designs and builds passively cooled adobe Earthblock houses in warm climates. He incorporates simple, inexpensive, natural systems to help heat and cool buildings for the rich and poor.
Hallock: Passive cooling is the use of the natural elements—sun, wind, shade—to make your living environment cool without the use of power. Historically, people did stay cool at the equator and warm in Greenland before we could plug in. So we are not so much pioneers as we are historians.
But natural elements are often ignored. For example, instead of using sunlight or CFL bulbs for daytime lighting, many people still use incandescent bulbs which waste around 90% of their energy as unwanted heat that further taxes air conditioners and energy use. Although you can augment convective airflow with solar fans, Hallock says that passive cooling doesn’t have to be expensive. It starts with knowing how the sun creates shady and hot sides on your structure.
Hallock: There’s a lot of things you can do to reduce your energy footprint of your home and many of those cost a lot of money. But there’s maybe 20 of them out there that are free. Orientation, shading, ventilation—things of that nature that will reduce the cost of energy. First of all, pay attention to where the sun is, in the morning and in the evening, and what parts of your house are warm or cool at those times of day. And use windows, opening and closing the appropriate windows, blinds. If you don’t have the ability to ventilate, appropriately, you could install some low or high windows to provide for passive ventilation. The additional cost of putting in some venting windows is going to have a quick payback in your energy costs.
Architects and energy specialists use natural cooling principals in new and existing buildings. Vegetation and eves for shade, solar chimneys, hallways, cupolas and clerestories are a few designs that can create convective airflow. Greg Madeen is an environmental architect who offers some simple tips about passive cooling.
Madeen: When it’s hot and dry, you can improve indoor comfort by adding thermal mass to reduce temperature swings. Adding humidity also helps. Plants in clay pots do both. Opening windows at night and closing them during the day is an easy routine. When its hot and humid, using natural cross-ventilation is key. Opening a smaller up-wind window and a larger down-wind window, opposite each other, increases your air speed. Moveable partitions can then funnel airflow. There’s many simple ways to lower energy costs while improving indoor comfort.
But Gordon Heinrich, a high performance-building consultant, says there’s another important aspect to passive cooling—insulation—which can often be installed by home and business owners for a fast payback.
Heinrich: One of the cheapest ways to keep the heat out in the summer and the heat in during the winter is by increasing your insulation, including radiant barriers. A radiant barrier looks like a large piece of aluminum foil stapled in your attic. It can reduce your cooling/heat load up to 40%,(Can only expect from 2%-10% savings on correctly installed radiant barrier) reducing the amount of air conditioning that you use, the amount of electricity. That saves energy, money and can reduce your carbon footprint for your home or business.
Whether you’re a business owner, renter or homeowner, smart use of the cool and hot sides of your structure can help reduce reliance on air conditioning, saving energy and money. Tax credits are available for improvements such as insulation, exterior doors, skylights, windows and weatherization. For more information about passive cooling, please visit us at goordirtradio.org.
Shift happens, from the bottom up, when enough people learn about their options and make beneficial changes. We urge you to check out issues you care about and get involved in the move toward sustainability.