Cooling a house with Shrubs, Trees and Vines

Trees - or vines and shrubs - around a house can be much more than just an aesthetical element: their shade can be a strategic element in your home's cooling.

Windows and roofs may absorb heat and, consequently, increase your air conditioning bill. Incorporating trees in your house landscape may reduce these cooling costs.

Trees and bushes may also be planted and located to provide a conduit for breezes and winds, or to reduce snow problems: see Windbreaks.

 
Trees, Shrubs, Wall Vines

Trees, shrubs or wall vines are excellent to shade a home. Just choose the plants carefully, according to your purposes.

Before planting trees or other plants, you should know their characteristics: future size, foliage density and crown shape, or if they are of evergreen or deciduous type.

The foliage density, the crown height and spread or the maturing cycles of the plants vary considerably and may have huge and very different impacts on your home cooling requirements. Just pay attention to them:

- Trees with high canopies are useful for shading roofs and large portions of the building structure.
- Shrubs are particularly appropriate for windbreaks and for localized shade for windows.
- Wall vines are particularly suitable to reduce summer heat and radiation.
- Vines in pergolas are excellent for home's cooling and shading

Note:
Besides shade, trees and shrubs provide cooling by transpiration - that’s why grounds around the house should involve lawns and plants, instead of pavement.


Shade & Deciduous Trees

Use deciduous trees, to avoid the sun heat to be blocked in winter. In cold and temperate climates, avoid evergreen trees – they provide inconvenient shade in winter.

Trees with low crowns can be planted to the west/east side of the house, where shade is needed from lower afternoon sun angles.

Main solar protection is provided by trees located in the south side of the house (in the northern hemisphere) or in the north side of the house (in the southern hemisphere).


Vines, Bushes and Shrubs

You may plant bushes or a row of shrubs to shade patios or driveways, or plant an hedge to shade a sidewalk. Indirectly they are a way of cooling your home. 

Planting bushes, shrubs and vines next to your house's walls may be an excellent cooling strategy. They will create dead air spaces that will insulate your home and cool it all over the year. Just take some cares.

Do not plant the bushes and shrubs too near the walls. The adult plants shouldn't be to close to your house's walls and foundations: they should be at least a foot away (30 cm) of the house's walls.

Climbing vines may damage the house structures or its walls (in the case of clinging vines) if they are planted too close to the house. Pay attention to their characteristics.

Notes:

- If wetness and humidity are among the problems of your climate zone, you should avoid plants near the house's walls. The ventilation of the walls through wind is absolutely necessary in this case, since it keeps the home and soil dryer.

- Bushes and trees can be used to keep the air conditioning unit in the shade, reducing its energy demands.

- Planting bushes and trees in an unplanned way can also clash with renewable energy and solar systems. Towering trees can block sunlight to solar panels (yours or those of your neighbors).


Vines

There are very different kinds of vines, climbing and behaving in different ways. They are usuallly grouped in three main species:

- Clinging vines stick to solid objects, and develop aerial roots into the smallest of crevices. They can damage the walls, especially brick walls. These vines comprise species as trumpet creeper, winter-creeper or climbing hydrangea.

- Twining vines as kiwi, bougainvillea, morning glory, american bittersweet, honeysuckle, american wisteria, are fast-growing species that need something to twist around and to support them as they grow.

- Vines with tendrils: grape, passionflower…  These vines need strings, wires, or other supports to grasp onto.