Passive Solar Home Design: Letting the Sun do the Work

Posted: April 5, 2019 Author: zach

If you are planning on building a new home or contemplating a remodel, it might be worth your while to consider the benefits of passive solar design before you approve those final plans.  Although still not as popular as many renewable energy options, passive solar design can significantly reduce your energy consumption through eco-friendly techniques.

Passive solar design relies on a building’s site, materials, and orientation to either capture or avoid thermal energy from the sun, depending on your seasonal needs. The purest designs combine several passive solar features to produce natural climate control, or at least environments requiring little heating and cooling.

Southern Exposure is the Key to Passive Solar Design

We have all heard about southern exposure but has anyone stopped to think about what that actually means? In passive solar design, the southern exposure is critical to site selection and building orientation. Why? Because the most light comes from the South with the least amount of accompanying heat. The key to passive solar design is using southern facing windows to accept light and transfer the corresponding heat to materials inside the home, for later release when needed.

Thermal Mass and Direct Gain

To capture and release thermal energy, materials with high thermal mass are utilized. Concrete, brick, and stone are commonly found in such applications. Each is capable of absorbing significant amounts of heat during the day and slowly releasing it throughout the evening to normalize the interior temperature of your home. This concept is called Direct Gain and can be enhanced at times by using water-filled containers to effect even greater transfer of heat.

Indirect Gain is Also an Option

Even if your home does not have southern facing windows, passive solar can still work at your site. Indirect Gain can be produced by creating an exterior masonry wall, normally eight to sixteen inches thick on the south side of your home. A sheet of glass is hung just a few inches from the wall. The sun’s energy passes through the glass and collects in the thermal mass of the dark wall. Hours later, this heat is slowly released into the interior of the home, bringing the living space up to a pleasant temperature. This set-up is also called a Trombe Wall.

You May Already Have an Isolated Gain Features

Sunrooms and solariums have long been part of some regional architecture, although designed more for aesthetics than energy conservation through Isolated Gain. Sunrooms are versatile.  They can either cut off the heat of the sun from the rest of the house or capture and direct it to the interior.

Landscaping, Shade Structures, and Air Flow Also Contribute to Passive Solar Design

There are many other techniques inherent in good passive solar design.  Landscaping, shade structures, and air flow are a few of the ways sunlight and heat can be manipulated for your comfort. Each passive solar home is unique in its design, as success is wholly dependent on the site and local climate. But one thing is consistent, incorporating passive solar design in your home’s construction will reduce energy consumption. For this reason alone, it is worth considering before you break ground on your eco-friendly dream home.