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)
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!
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.
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.
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.