Trees make a big difference in home heating/cooling costs

Willow shade trees, Bayside Cabins in Bigfork

Willow shade trees, Bayside Cabins in Bigfork

By Catherine Haug, May, 2015, in honor of Arbor Day (Photo, right, by C. Haug)

Here in the green Flathead, we perhaps take our trees for granted, and forget that they provide many other benefits besides beauty. Here’s just a short list:

  • Shade;
  • Windbreak;
  • Carbon sink (store carbon in the ground rather than as particulates and CO2 in the air);
  • Ground water filter;
  • Erosion prevention;
  • Food (as fruit, nuts); and
  • Medicine.

Trees for shade and windbreaks is the topic of this posting.

When landscaping your property, be mindful of the ways that smart placement of trees can significantly reduce your home’s energy consumption. In fact, they can be as effective as other energy-saving home improvements, such as insulation and air-sealing measures on windows and doors. (1)

According to the Department of Natural Resources, a minimum of three large shade trees planted around your home can reduce air conditioning costs by 30%, if sited properly. (1) In open areas, properly placed tree-windbreaks can cut fuel consumption (for heating) by 25 – 40%. (2)


The proper selection and placement of trees (by type and size) can maximize the benefit of shade/absence of shade.

When placed on the sunny sides (south and west) of your home, deciduous trees:

  • provide shade to cool your home in summer, and
  • let the sun shine through to warm your home in winter.

Additionally, provide shade for all hard surfaces such as driveways, patios and sidewalks to minimize landscape heat load (1).

If you live in an arid area that experiences significant heat from sunrise to sunset, plant deciduous trees to shade east-facing walls and windows from 7 to 11 a.m. and west-facing surfaces from 3 to 7 p.m. during June, July, and August. (3)

  • Trees with mature heights of at least 25 feet should be planted 10 to 20 feet east and west of the house. (3)
  • Plant smaller deciduous or evergreen trees with lower limbs northwest and northeast of the building to provide late afternoon and early morning shade. (3)


When I was growing up, Mom and Dad took me across the highline from Bigfork to Scobey to visit family and friends. This trip impressed me with two weather related things:

  • The prevalence of ‘snow fences’ across open fields, to minimize damage to buildings and soil from winter blizzards;
  • Tall poplar trees around every home in an otherwise open field, to protect the home and outbuildings from wind.

Heating the home can be costly in winter, and even more so if there is no protection from cold winter wides, especially those from the north.

While the deciduous poplar trees were used in Eastern Montana, evergreens such as Douglas fir, grand fir, spruce, cedar, juniper and pine trees provide the best protection in Western Montana. The density of their needles intercept and slow the force of winter winds.

However, when planted on the sunny side of the home, they block the sun in all seasons, which is advantageous in the summer, but not in winter when the sun’s heat would be beneficial. Therefore, site evergreens on the north side of the home for maximum benefit. Depending on wind patterns in your local area, it may also be beneficial to plant on the west and northwest sides of a building (3).

Windbreak trees can be planted in straight or curved rows or in linear groupings. They should be close enough together so their crown edges meet within a few years without overcrowding.

Note that wind protection extends downwind ten to twenty times the windbreak height, so the trees need not be planted close to dwellings to be effective. Keep in mind that snow drifting will be the worst at two to three times the windbreak height downwind. (3)

Related articles on The EssentiaList:


  1. Northwester Energy’s Energy Connections, April 2015
  2. Smart Landscaping and Energy Efficiency (
  3. Planting Trees for Energy Conservation: The right tree in the right place (

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