Tag Archives: shade

I keep track of my year-over-year electrical use so I can tell, in a general sort of way, which of my energy savings methods is working and which give the best return on investment.

General background on my house

  • 1,100 square feet
  • Single story
  • Built in 1939 out of bricks laid in a Flemish bond pattern
  • One human occupant, two cats
  • Central air conditioning (heat is gas)

The numbers

2011 is the baseline year: 6,813 kWh used – highest usage is in summer with the A/C running.

In March, 2012, I had additional insulation blown into the attic to bring it up to code (R38) and 5 roof vents put in.

      • Project cost: $1700
    • Energy savings over 2011: 407 kWh
    • Cost savings over 2011: $52
    • Amount of time to see return on investment: 33 years

In May, 2013 dad put up three cheapo exterior blinds from Home Depot across my front porch which faces west. It’s also the side of the house with my biggest windows – ugh! I also started paying meticulous attention to my daily energy use by checking my account on aps.com. I am on their 7PM to noon plan whereby energy is less expensive during those hours and more expensive during peak usage times from noon to 7 PM. I found that by keeping the thermostat at 86° during peak times and 84° during the other times in the hottest months actually saved me money over trying to sweat it out with NO A/C during the hottest part of the day and suffering through indoor temperatures often in excess of 92°.

  • Project cost: $40
  • Energy savings over 2012: 1536 kWh
  • Cost savings over 2012: $115
  • Amount of time to see return on investment: Immediate!

APS 2011_2012_2013

So the winner by a long shot is “exterior shades and paying attention to thermostat settings”!

I’m glad I insulated and vented the attic too – don’t get me wrong. I can feel the difference the insulation has made especially in the really hot months when the heat build-up in the attic would make my interior walls warm to the touch. That doesn’t happen anymore.

I’m still working on strategies to keep even more heat off my house in the summer to stop the bricks (thermal mass) from heating up. Here’s one of my strategies from a few years ago – use summer vines to shade the porch. This worked pretty well and had the added benefits of being pretty and green and also, being a plant, transpiring a little, thus adding a tiny bit of cooling. But it wasn’t solid shade like the blind, and there was no way of covering the middle bay of the porch which leads to the front door.

passive shade, wix 071209 004

Here’s the front of the house with the blinds – notice that all three porch bays have a blind on them. They did an amazing job shading this western side of my house, especially in the evening when the sun was low enough to slide under my tree canopy.

front yard1 052213

Plans for more energy savings in 2014

With our intense summer heat and with my biggest windows on the HOTTEST side of my house (West), I’m investing in a “hedge fund”. What’s that you say? Yes – a hedge fund – basically some tall shrubs placed strategically along the inside of the fence surrounding the front of my property. These shrubs will ultimately grow to a height where they will act to block that low, setting sun in the summer, thus acting as another “solar baffle” to keep the heat off my house.

Basic model of the west side of my house at 6 PM on June 22nd without tall “solar baffle” shrubs.  Note the low sun angle in the evening allows the sun to shine right under my tree canopy and hit my house – including my windows.
Basic model of the west side of my house at 6 PM on June 22nd without tall “solar baffle” shrubs. Note the low sun angle in the evening allows the sun to shine right under my tree canopy and hit my house – including my windows.
Basic model of the west side of my house at 6 PM on June 22nd WITH an example of a tall “solar baffle” shrub.  Note the shadow of this shrub (6 ft) now blocks out that low sun angle and shades my front porch.  The idea is to plant a variety of “solar baffle” taller shrubs in the yard that will serve as another layer to protect against that low summer setting sun while simultaneously making the air around my house cooler with their evapotranspiration.
Basic model of the west side of my house at 6 PM on June 22nd WITH an example of a tall “solar baffle” shrub. Note the shadow of this shrub (6 ft) now blocks out that low sun angle and shades my front porch. The idea is to plant a variety of “solar baffle” taller shrubs in the yard that will serve as another layer to protect against that low summer setting sun while simultaneously making the air around my house cooler with their evapotranspiration.
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Climbing nasturtiums are overtaking the eastern wall of the propagation area.  Although the leaves and flowers are edible (and delicious), I don’t eat from these particular plants because they are watered with greywater from the outdoor shower.
Climbing nasturtiums are overtaking the eastern wall of the propagation area. Although the leaves and flowers are edible (and delicious), I don’t eat from these particular plants because they are watered with greywater from the outdoor shower.

Have you ever noticed how the low angle of the rising and setting sun can really heat up your house?  Living in the Sonoran desert, it’s hard to avoid noticing when your house starts to heat up before 8 am!

However, trying to block that sun can be tricky due to the angle.  While trees provide shade overhead, that low sun is going to slip right under them.  It’s the same with porches on the east and west side of the house - the sun will sneak under those porches early in the morning and in the evening.

So what can you do?

In my case, my solution was to design a multi-purpose shade house that runs across the back of the house.  It contains my plant propagation area, outdoor shower and the hen yard with two built-in compost piles.  The idea was that the structure itself, along with some trellised grape vines (deciduous in winter), would help keep the sun from hitting the east side of my house in the morning, preventing that early morning heat gain that’s so undesirable in the summer months.

Before:  This picture of the eastern façade of my house was taken at 7:41 am on September 26, 2006.  The high was 102° that day.
Before: This picture of the eastern façade of my house was taken at 7:41 am on September 26, 2006. The high was 102° that day.

I tried to address as many permaculture principles as possible in creating this project.  The following principles really stand out:

  1. Observe and Interact – I observed that the low rising sun was prematurely heating up the mass of my house early in the day and transferring that heat inside.  In the hot desert summer, this was costing me money on extra electrical usage.
  2. Catch and Store Energy – In the summer, I want to deflect the sun’s energy away from the house (to save on the amount of electricity I use cooling my house).  In the winter, I want to capture that sun for passive solar gain.  Deciduous vines are perfect for this.
  3. Obtain a yield – Eggs, grapes and compost are all generated in various parts of the shade house.  Plus I save money on electricity and water because the shower greywater waters my grapes.
  4. Integrate Rather Than Segregate (also known as “Stacking functions”) – This design is a fairly decent application of “stacking functions” whereby each individual element in the system supports several functions and each function is supported by several elements.  While the ultimate goal of the project was to passively shade the eastern façade of my house and save money on electricity, the shade house in its entirety does more than that.  The combination of the structure and plantings does shade this façade in summer and still lets light through in the winter.  The plantings are watered by the outdoor shower.  The floors of both the henyard and propagation area are infiltration basins that collect rainwater runoff from the roof and compost woody mulch in place.  The two compost bins in the henyard receive kitchen and yard waste and are turned by the hens.  That compost is used in a potting soil mix for the plants grown out in the propagation area and also as top dressing for the vegetable beds.
After:  The eastern façade of my house after the shade house is fully constructed.  You can see a lot of the back wall of my house is blocked by the physical structure.  As the grape vines grow, I’ll get even more vertical shade in the summer, but I’ll get passive solar gain in the winter when the vines are dormant.
After: The eastern façade of my house after the shade house is fully constructed. You can see a lot of the back wall of my house is blocked by the physical structure. As the grape vines grow, I’ll get even more vertical shade in the summer, but I’ll get passive solar gain in the winter when the vines are dormant.
The beginning of the shade house.  You can see my exterior blinds covering my windows in the background.  It’s amazing how much sun and heat exterior blinds can block.
The beginning of the shade house. You can see my exterior blinds covering my windows in the background. It’s amazing how much sun and heat exterior blinds can block.
My dad, a civil engineer, built the shade house, but it was up to my mother and me to do the endless painting.  So much painting…
My dad, a civil engineer, built the shade house, but it was up to my mother and me to do the endless painting. So much painting…
The hen yard with built-in compost bins.  The hens perch over the bins at night and drop “nutrients” into the compost while they sleep.
The hen yard with built-in compost bins. The hens perch over the bins at night and drop “nutrients” into the compost while they sleep.
Hens processing green waste into eggs!  Note the deep litter on the floor of the henyard.  This serves as a rainwater infiltration basin for any rainwater that runs off the back part of the roof.  You can also see into the side of the propagation area in the back.
Hens processing green waste into eggs! Note the deep litter on the floor of the henyard. This serves as a rainwater infiltration basin for any rainwater that runs off the back part of the roof. You can also see into the side of the propagation area in the back.
Four young ladies huddled in the same nest box.
Four young ladies huddled in the same nest box.
The corridor between the back of the house and the shade house.  The metal gates can be locked and I can open my back windows to let airflow through while still maintaining safety without ugly security bars.
The corridor between the back of the house and the shade house. The metal gates can be locked and I can open my back windows to let airflow through while still maintaining safety without ugly security bars.
Winter crops being grown out in preparation for planting season.
Winter crops being grown out in preparation for planting season.

 

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