Sunday, December 12, 2010


How I Got Started

I've wanted to get solar panels for at least the past 10 years. Every time the idea came up, I was either too busy on other projects or the funds were not available. This year was different. In October of 2010, I was doing my annual "price out a whole house solar array" when I came across a wholesaler called Solar Home. 
They had very good prices for complete solar systems around $3.40/watt. At the time that was an amazing deal, (
Today you can get the materials for an entire array for under $1.50/watt). You could barely buy the panels for that price let alone all the roof mounting hardware (racking) and a grid-tie inverter. But there it was, just waiting for me to buy it. Also there were some amazing state and federal rebates and credits totaling 55% of the cost of the whole system.
Just then, a Wells Fargo solicitor called trying to get me to take out a home equity loan. I replied with my usual, "No thanks but I am not interested in a home equity loan," but then I paused. "Wait a minute, that's it! I can take out a loan for the solar panels and when the rebates come in, I can pay it off. "I'll take it!"

Before we bought a solar system large enough to power our whole house, I had to figure out how much electricity we required each year. Being the big nerd that I am, I already knew that and kept a spreadsheet for my monthly usage for the past 4 years. 



Our average electric usage, (since we moved into our new house) was 1080 kilo-Watt-hours/month. I should add that we live in a 5000 sqft house that is fancy but fairly energy efficient (R-13 in walls, R-38 in the attic, low-e glass windows). It has a ton of south-facing windows that provide plenty of sunlight in the daytime. To make it more efficient, we also did the following shortly after we moved in:
  • Swapped out incandescent lights for CFLs (there were almost no bulbs in the house when we moved in anyway).  
  • Added curtains to cover windows (so we can reduce direct sunlight during the summer months).
  • Added an attic fan (to help vent some of the heat from the attic).
  • Added more insulation around the cold condenser pipes running from the central A/C compressor and condenser.
  • Added more insulation to low spots in the attic (some places got missed when they built the house). 
Our average electric usage would have been about 35-45% higher had we not done these improvements. In any case, after all these improvements, 1080 KWH/month is our baseline electrical usage. 



It's a Good Start But It's Not Enough: 

My target 6.42KW solar system will only generate 960 KWH/month of electricity.  In order for the solar panels to cover 100% of our house electric needs, We needed to shave over 120KWH off our total usage.
I recently found a really cool website on how to save electricity
http://michaelbluejay.com/electricity. It is one of the best ones I've seen about energy conservation and saving money on all your utilities.

The best way to get your house onto solar power is to reduce your use first. Why pay for a super expensive solar system when with a tiny bit of tweaking you can get by just fine on a smaller and cheaper one?


Using a Kill-A-Watt meter, I was able to plug in and measure the energy usage of almost every appliance in my house. Some things like the refrigerator you leave plugged in to the meter for a few days to get the average usage of the appliance.














I made a spreadsheet that shows what every appliance uses and what it is costing me to run.

It's all About duty cycle:

Surprisingly, some appliances use a lot of energy but don't really contribute to your total electric bill that much. Others don't consume a lot of energy but over the whole month it adds up to a lot. For example the glow-in-the dark clock on our microwave oven uses more energy in 24-hrs than the microwave oven does to cook something for 2 1/2 minutes.


Each of my two super-energy efficient desktop PCs (Intel i-3 processors with WD green hard drives and 80 plus power supplies) that we keep on 24-7 use more energy than our electric range does to cook a meal 30 minutes each day. Obviously there were things that we could still do to reduce our total energy usage.

My goal in reducing our KWH consumption was to reduce energy usage without sacrificing convenience and luxury.

To make a long story short, in addition to the improvements I did when we moved in, I also did the following:

  • Swapped out the electric clothes drier to a gas one, (reduced by 130KWH/month)
  • In the daytime (except summer), open curtains and turn off all lights (20-45KWH/month reduction).
  • Set the computers to go to sleep after 5-10 minutes of being left idle. (15KWH/month per PC).
  • At bedtime, turn off all lights and use LED night lights (3 KWH/month reduction).
  • Use only LED Christmas lights, (234 KWH/month reduction in December).
  • Added a ceiling fan in the main living space, (estimated 200KWH reduction in the summer months).
  • Get the kids to actively turn off the lights when they aren't using them (work in progress). As part of their weekly jobs, one of the jobs is titled the Energy Conservation Advocate.
As you can see, the clothes drier brought me all the way to my goal with the other stuff just being extra. 
















That was so easy that I want to see how much we can reduce it further. After all, why waste energy and money if you don't have to?

I still want to do the following additional energy reducing enhancements:

  • Upgrade our PCs with solid state hard drives (3KWH/month per PC).
  • Add more attic ventilation. 
  • Air seal windows, doors, light fixtures, exterior plug sockets and switches. 
  • Solar Tube skylight in the dining room and hall way, http://www.solatube.com/
  • I am anticipating that having 500 sqft of solar panels on our south-facing roof will reduce the solar load on my home as well.