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Reduce Energy Costs

The sun is our original and ultimate source of energy. Understanding how to control and use sunlight gives us new and better ways to make use of solar energy.

Every homeowner should take sunlight into consideration to reduce their energy costs. If there is sun shining on your house, it has some effect on indoor temperatures, either positively or negatively. Windows are one of the biggest areas of concern when it comes to the influence of sunlight on your home's heating and cooling.

A Little Solar Science

Solar heat gain, sometimes called passive solar gain, is the term used to describe how a home is heated by solar radiation. Sunlight contains different wavelengths of radiation. Objects in sunlight absorb short wavelengths of solar radiation, which is what causes them to warm up.

When sunlight shines on a window, the amount of solar heat gain inside the room depends on how much radiation gets through. There are multiple factors involved here, including the number of hours of daylight, whether the sky is clear or cloudy, the angle of the sun in the sky, and the direction in which windows face.

Taking Advantage of Solar Heat

Controlling solar heat gain is not all about keeping solar radiation out. Homeowners spend money to heat homes as well as to cool them, and solar heat is free heat. This means the best methods for you to control solar heat gain will depend a lot on the prevailing climate where you live and the amount of sunlight your home receives. Homes in temperate climates can benefit most from flexible solutions that let in winter sunlight but block sun in the summer. Homes in extremely sunny climates will need to rely most on methods for keeping sun out, and vice versa for homes in cold climates or areas with little regular sun.


Windows Make a Difference

Windows themselves can be constructed to minimize solar heat gain. If you replace the windows in your home, look into energy-efficient options such as double glazing or ones that feature low-E coatings, which are made from transparent metallic oxides applied to the surface of the window. These coatings reflect long wavelengths of radiation, including the infrared radiation that we feel as heat, but let the visible light pass through. Low-E coatings help to control energy costs in both summer and winter, keeping summer heat outdoors but holding winter heat inside the house.

An alternative you can use to block some of the sun's rays on existing windows is solar film, which functions similarly to low-E coatings. There are multiple types of window films available, including insulating films, solar films, and privacy films, so you need to make sure you choose a film with the right characteristics to block solar radiation.


Window Treatments

Solar Shades are one type of window treatment to help manage solar heat gain. Blinds and shades can also offer significant protection against solar radiation, especially if you choose the right types for your home.

Blinds enable you to completely cover the window or let a little bit of light through the entire window surface. Horizontal blinds enable you to block most sunlight, but you can also adjust the blinds so that a little bit of sun is reflected up onto the ceiling, which will help to illuminate the whole room. This is a great choice for people who prefer natural sunlight but need to block the full intensity of sun.

Shades also enable you to block most of the light, especially if you choose a blackout version. Cellular shades offer improved energy efficiency, as they help to insulate the window from heat radiating through by trapping air in the specially designed honeycomb-shaped pockets.

Vertical Blinds are ideal options for covering glass doors or large windows. They are made in a range of opacity options, giving you the ability to control light when you louver the vanes. While vertical blinds are the most familiar to many homeowners, other alternatives are now available, including panel track blinds and vertical cellular shades. Vertical cellular shades offer better insulation, as do horizontal cellular shades.


Outdoor Solutions

Efforts to control solar heat gain may benefit from extra solutions outside of the house, especially in hot climates and in areas with a lot of intense sunlight. If sunlight is blocked from ever reaching the window, then the amount of solar radiation absorbed into the house is greatly reduced.

Any objects that provide shade to the house and windows help to minimize solar heat gain. Where blinds and shades block sunlight at the inside of the window, awnings and roof extensions block sun from reaching the outside of the window. Installing an awning is one of the simplest ways to shade a window from the exterior, and it also provides extra shade outside so you can enjoy sitting outdoors. A retractable awning provides the same flexibility as indoor window treatments, allowing sun through the window when you want it.

When building a new house or addition, planning a roof extension is a more durable alternative to an awning. But roof extensions are very difficult to incorporate into existing rooflines, which makes awnings more practical for most existing homes.


Using the Landscape

Even farther from the house, you can use landscaping to provide extra shade. Planting trees or tall shrubs is a great way to provide shade to a house, though it may take several years of growth before you receive their full benefit. In temperate climates, deciduous trees offer the best advantages for solar heat control, as summer leaves provide shade while bare winter branches allow sunlight through to the house. In sunnier climates, trees that keep their foliage year-round are better choices.

A house's orientation also affects the degree of solar heat gain. South-facing windows receive the most sunlight, while north-facing windows receive the least. Houses that are oriented to account for solar radiation help their homeowners to better manage energy costs. For example, a house in a colder climate can take advantage of large south-facing windows to bring in as much solar heat as possible, while in a warm climate, smaller windows on the south side of the house will minimize heat gain.

Even in an existing home, being aware of orientation can help you make the smartest choices for controlling solar heat. Rooms that receive the most sun need the most help from window treatments or other means to create shade. Rooms with little or no direct sun will not experience a lot of solar heat gain, but may benefit from measures to make the most of the available light such as light-colored walls and furnishings.

Let There Be Light

Understanding and working with solar radiation will help you reduce your energy costs. By maximizing solar radiation when you want it and blocking it when you don't, you will improve both heating and cooling costs, as well as giving yourself the benefit of free, natural heat and light for your home.

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