What makes a comfortable home? Lots of natural light and fresh air, comfortable warmth in winter and pleasant coolness in summer. All of this is possible with passive solar design. Let’s break down what passive solar is and how it works.
Passive solar design is based on a fundamental understanding of how sunlight interacts with buildings. Knowing these principles, we can naturally heat, cool, ventilate and light living spaces by reflecting, absorbing and transmitting solar light and warmth.
By itself, passive solar design requires no special equipment, ongoing investment, or effort. All objectives are met through thoughtful design, material selection, and building orientation. Yet, these aspects should be considered before construction begins, as changing them later will be hard or just impossible.
Solar panels also love the south-facing side. If you want to install a solar system, make sure you have enough space on the southern slope of your roof.
South-facing windows capture the most sunlight during the day, especially in the winter months when the sun is lower in the sky. The south side is best for playrooms, living rooms and spaces you spend most of your day in. The east side is ideal for bedrooms to wake up with the first rays of the sun, while the north side is good for rooms that don’t need daylight, such as the garage or bathrooms.
Windowsills can help increase the amount of light in the room. They should be light-colored and slightly angled to the room. This way, the sunlight falling on them will be reflected and scattered, making the room brighter. You may also use window light reflectors for the same purpose.
It costs us a lot to maintain a comfortable home temperature. Heating and cooling account for about a quarter of your electricity bill, according to the U.S. Department of Energy. Passive solar offers you two ways to give your air conditioner and heater a small break and lower your energy costs. Passive heating is achieved with the help of thermal mass and trees.
Thermal mass materials absorb, store and release heat. Common examples include concrete, brick, stone, and tile. During the sunny part of the day, sunlight streams through windows and warms these thermal mass elements. The absorbed heat is then released gradually throughout the cooler evening and night, providing natural warmth.
Thermal mass works best when combined with good insulation, slowing down the heat transfer process
Polished concrete floors or exposed brick or stone walls can be a beautiful design feature, while also providing thermal mass benefits. You can use them as an accent or incorporate them into your passive solar house plan. Large tile walls and countertops can act as thermal mass elements in kitchens, absorbing heat generated during cooking and releasing it later.
In summer, thermal mass materials work the other way around. Cooled down during the night, they keep your home comfortable during the day, slowly absorbing the sun’s heat to release it at night, providing passive heating.
Wind increases the rate of heat loss from your home. Even if the air temperature isn’t that low, the wind makes it feel colder. Evergreen trees or shrubs placed on the north side of your home can create a barrier that slows down and disrupts winds approaching your house from the north. This reduces the windchill effect on your exterior walls, keeping the heat inside.
Evergreens also provide a secondary layer of insulation. They can act as a snow catch, trapping snowfall near the foundation. This trapped snow acts as an additional insulation layer, further reducing heat loss from the house.
In summer, southern rooms may face the overheating problem, when the sun turns them into a greenhouse, trapping heat inside. The best way to avoid this is to protect south-facing windows with a special awning or to extend the southern slope of the roof. The summer sun rises high in the sky and this awning will safely hide you from its scorching rays, while not preventing the low winter sun from entering the room.
Ponds or fountains add a cooling element to your outdoor space, particularly in drier climates.
Trees planted south and west of your home or vines on pergolas or south-facing walls can also provide shade in summer, acting like a natural awning. Their leafy canopy blocks the sun’s rays during hot months, keeping your home cooler. In winter, they shed their leaves, allowing sunlight to penetrate windows for natural warmth.
Consider prevailing wind directions when designing your house layout and window placement. This will help you maximize airflow through the space.
Natural ventilation is all about using nature’s forces to bring fresh air into your home and remove stale air, instead of relying on fans and air conditioners. There are two main drivers of natural ventilation: wind and temperature differences.
By opening windows and vents on opposite sides of your home, you can let winds blow through your house, forcing hot and stuffy air out faster. During cooler nights, this also cools the thermal mass elements which can then absorb heat slower the next day when the sun warms the space.
Stack ventilation uses temperature variations to induce airflow. Warm, less dense air rises, and buildings can be designed to take advantage of this. For example, opening high windows allows hot air to escape, while opening lower windows on the opposite side draws in cooler air.
Passive solar design not only reduces energy consumption and reliance on traditional HVAC systems but also creates a more comfortable and sustainable living space. Yet, it’s just one piece of the puzzle. Introducing energy-efficient practices, using renewable energy sources like solar panels – there are so many ways to make our homes a better place. Stay tuned and check out our articles for more sustainable tips.
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Years of experience in translation and a love of nature help Julia find the right words to encourage going solar. She joined the team in 2023 and is happy to make her contribution to a greener future.
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