What you plant (and where you plant it) can impact your utility bills.
If you want to avoid high energy bills from running your AC at full blast all summer long, there’s one often overlooked feature that can help: Your landscaping can help to keep your house cool in the summer by adding shade to areas that would otherwise absorb a lot of heat. Adding plants and other smart landscaping features can make a big difference in keeping your interior cooler and reducing utility bills.
According to the U.S. Department of Energy, trees can cool the surrounding air by as much as 6 degrees Fahrenheit—and because hot air rises, while cooler air tends to settle near the ground, the temperature in an area shaded by a tree can be up to 25 degrees F cooler than unshaded blacktop. For your home, this means that shade trees, as well as hedges and even vines, can play an important role in saving energy during warm weather. While shade trees can take a decade to mature, and tend to be a long-term investment, hedges can fill out in about three or four years, providing faster shade. Using trellised vines for an even faster-growing shade can give you results in a single season.
The sun is strongest on your windows on the East- and West-facing sides of your house because you will get the most direct sun through windows when the sun is low on the horizon. To reduce heat absorption through windows, plant your shade trees and other plants on the East and West sides of your home. Make sure to take into account the area that a plant's root system will need, and space them safely from your home to avoid damage to your foundation.
In areas that are cold in winter and warm in summer, deciduous trees and shrubs are an excellent choice because they will drop their leaves in fall, shading less during winter months when sun exposure is desirable for heat retention. In areas where sun exposure is never desired, like in hotter climates, you can choose coniferous trees and shrubs that will hold their leaves or needles all year, continuously shading your home from sun exposure. In colder climates, you might choose less shade on the sunny sides of your home, allowing sunlight to help warm your house.
If you live in a warmer area where creating a cooling breeze is helpful, having shade trees on one side of your house and then a wall, a hedgerow, or fence on the other side can have a wind tunnel effect, encouraging a breeze. Air will move faster below tree branches than through them, so trimming the lower branches of shade trees will help to create more air circulation that can help with cooling.
While your air conditioner is designed to work in the summer heat, adding some shade can help it to use a little less energy. Planting a coniferous tree that will shade your unit all year long is a good choice, but you will need to remove needles at least once per season to make sure your AC is clear of debris. Avoid planting anything within two to three feet of your AC unit to keep the air around it moving freely.
Highly reflective materials that could reflect heat and sunlight onto your house, like lightly colored gravel or concrete, can increase your home’s interior temperature. In general, large, unshaded areas, especially on the East and West facing sides of our home will make it warmer inside, so larger shade plants are a better idea for these areas. You should also avoid dark-colored awnings or patio covers because these will absorb sunlight in the form of heat, and hold in heat close to your house.
