March 25, 2017
Planting trees can be useful for more than just landscaping aesthetics. The sun’s heat can increase cooling costs during the summertime, and strategically placed trees can block the most powerful rays from shining directly on your roof or through your windows. Unfortunately, reducing solar heat gain inside of a home is not quite as simple as planting new trees or letting current ones reach maturity. The U.S. Department of Energy points out that there are several important variables that homeowners need to understand if they want to create the optimal shading strategy for their property.
Know the Local Climate
In colder climates, solar heat gain is a welcomed occurrence. When the sun shines through windows during the wintertime, its rays warm the inside of a home and reduce the need for artificial heat from a furnace or radiator. At the same time, winter winds can make a home cooler, especially if there is no foliage to block the gusts from hitting the sides of a house. In warmer climates, homeowners often want to avoid the sun year-round, and they welcome the wind as a natural source of cooling. Homeowners should understand their specific shading needs before starting a major planting or tree removal project. There is no one-size-fits-all strategy.
What Trees Work Best?
The U.S. Department of Energy (DOE) suggests that in four-season climates, deciduous trees are the best option: they provide the ideal amount of shade for each season. In the summer, leaf cover will provide the necessary barrier to block out the sun; during the winter, leafless branches will allow for many of the rays to shine through and provide solar heat gain for the home. Evergreen trees, on the other hand, are superior for wind blocking. The DOE recommends planting coniferous trees or shrubs by the sides of a home to deal with wintertime wind gusts. Offering continuous shade, evergreens are also a wise option for homeowners who want to avoid solar heat gain throughout the year.
In terms of shading, placement matters as much as the tree type. To block summertime rays, the DOE recommends planting deciduous trees with tall, wide crowns (of branches and leaves) on the southern side of your house. Doing this provides the maximum benefit during the hottest part of the day in the warmest months of the year. Shorter leafy trees, meanwhile, are most beneficial when planted on the western side of the home. The sun moves towards the west in the afternoon, but it is lower in the sky so that it may shine underneath trees with high canopies. Shorter trees will be able to block the afternoon rays. One notable exception to the placement strategy has to do with solar power. Solar panels need the maximum amount of sunlight possible, so creating shade for a roof that has solar panels is counterproductive and will keep the home from getting the full value of this renewable power source.
Patience Pays Off
One final bit of advice from the DOE is that patience pays off in the long run. Fast-growing trees will provide shade sooner than their slower-growing counterparts. Slower-growing trees live longer overall and have stronger branches and roots, making them better equipped to withstand high winds, heavy snows, or ice buildup. Also, because their root system is more developed, slower-growing species are more durable in drought conditions.
Other Consideration Factors
Other variables for tree placement include adult size and potential obstacles. It is important to know roughly what size an adult tree will grow to, in terms of both its height and crown width. This knowledge will save you from planting trees that lack the height to provide adequate shade and, more importantly, it will allow you plan seedlings or young trees the appropriate distance from your house (so they provide shade in adulthood without being too close). This will save the home from problems such as branches falling on the roof and roots damaging the foundation or plumbing.
Most people are knowledgeable enough to avoid planting trees directly under power lines, but it is also vital to understand the potential size of a tree’s crown. Full-size branches may grow to touch nearby power lines. If this happens, frequent trimming by a professional may become necessary. To avoid this, trees should be planted at least one-half of their mature crown width away from any obstacles.
If a property lacks mature trees, it could take years, even decades, before saplings grow to the size necessary to provide beneficial, energy-saving shade. Vines are quick-growing alternatives that can be planted at the bases of trellises or similar structures. These plants will grow upwards quickly, providing some shade within a matter of months (instead of years). Annual vines can cover a reasonably large area by the middle of the summer, so they should be long enough and dense enough to help with shading during the hot summer months. Preferable for colder climates, annual vines can be cut back during the winter to allow for beneficial solar heat gain.
Perennial vines need to be trimmed during the colder months so they can allow heat-giving wintertime rays to permeate. Another quick fix is to create shade over home’s air conditioning unit during the summer, which can increase the appliance's efficiency by up to 10 percent. Homeowners can also install shutters in front of windows that receive direct midday sunlight. Because heat passes through windows with ease (as opposed to insulated walls), simply closing the shades and curtains with the sun is blazing can have positive effects on summertime cooling costs.
An alternative to shading is to reflect the sun’s rays; this can be accomplished with “cool roofing.” A cool roof has reflective capabilities that keep the sun’s heat from being absorbed into the house. The unique shingles may have a lighter color, or they may use a special composite that has strong reflective properties – some of which has received Energy Star certification.
An upgrade to a cool roof may qualify for Property Assessed Clean Energy (PACE) financing. These programs, approved by local authorities, allow homeowners to finance energy-saving upgrades for no upfront cost, and then pay for them over time on their annual property tax bills. Therefore, homeowners can essentially use the money saved on summertime air conditioning bills brought about by their new roofing to pay for the improvement over the long-term.
Shading and Solar Heat Gain Can Be Powerful Efficiency Tools
The benefits of strategically placed shading are well-documented. Shade provides natural cooling, which can save on summertime air conditioning bills. And in cooler months, solar heat gain can help reduce artificial heating needs. In four-season climates, having a comprehensive plan for blocking the sun’s rays or letting them through, depending on the season, can lead to significant energy savings throughout the year – which is good for both homeowners and the environment.
Want to contribute to a greener planet by becoming more energy efficient at home? Contact Ygrene at (855) 901-3999; firstname.lastname@example.org.