Homes That Work With the Sun: Principles of Passive Solar Design

The sun is an exploding furnace of gas, and it is anything but passive. Designing your home for the best possible use of solar power is also a very active experience. So what is passive solar design, and why the name?

Passive solar design gets its name because it does not involve machines with moving parts. As a homeowner, the thought of no moving parts is often attractive. There’s nothing to break. However, the process of passive solar design does require a large amount of consideration. Passive solar design creates a home that collects and releases the sun’s energy at times that work for you. To design in this way, you need a deep understanding of your building site and the ways in which the building will interact with that place.

If you love the way your front yard tree provides shade for your home, you know something about passive solar design. However, to be a true designer you need to make an investment in building your knowledge of the site at the outset and make adjustments to the building and the site.

What do you need to know to begin to understand your building site and translate this into a good passive solar design?

Choosing a building site for passive solar design is more complex than it appears. You do not want to simply choose the first site with a lot of sun. To choose a good building site, you need to consider the latitude of the site. In part, the latitude determines the climate. Is this place hot in the summer and cold in the winter? Is it mild and humid all year round?

Track and understand how the sunlight changes over the course of the year or even the course of the day. You may think that the sun rises in the east and sets in the west, but where does it go in between? There’s a big difference between summer and winter sun angles. Build a home that changes with the seasons by capturing the sun’s rays when you need them. Online tools such as Sun Angle can help you calculate the altitude and declination of the sun at different times of the year. You need to know your latitude and longitude to use the program.

Walk around the site and map the ways in which major landscape features change the levels of sun, shade, and wind present on the site. Every small part of the world has its own micro-climates. Landscape features such as large trees and other buildings will change the amount of heat and light that are present on each part of the building site. Trees, walls, buildings and arbors also change the way the wind moves through the area. Be conscious of the ways in which any future buildings will change the sun, shade, wind and humidity on the site.

Where do you go first thing in the morning? The kitchen? The living room? If the sun is not too harsh, use it to warm living spaces in the morning and sleeping spaces in the evening. Orient the house on an east-west axis so that you can use the sun to your advantage. Strategically control shade and micro-climates to create the climate you want in each room. Use outdoor and indoor blinds and arbors to make certain rooms shadier at certain times of the day.

By using passive solar design, you can construct or renovate a home so that it requires fewer machines to heat and cool the air. For your budget and for your repair bills, that can only be a good thing.

Posted in Solar.

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