“I live in a 2000 square foot house. How many solar panels do I need?”

If I had a 200 watt panel for every time I’ve been asked this question, I would’ve solved the world’s energy problems long ago. Alas, I wish there was a simple answer to this question. The answer lies not in ‘how big’ your house is, but rather ‘how big’ your appetite for energy is. A simple illustration of two identically sized houses should shine some light on this topic.

Tommy and Eric live next door to each other in identical tract homes.

To the casual observer, the only obvious difference between Eric’s house and Tommy’s is the paint color. However, if we analyze the cost of operation of each of these buildings (yes although you may not like to think of your cozy little home this way, it is indeed just a building) we’ll discover dramatic differences in both the volume and application of energy.

Knocking on Eric’s door we discover he’s a friendly bachelor who works at home as an outside sales rep. He travels a lot on business, so he often asks Tommy to feed his cat. Of course, Eric has the usual things, a 60” flat screen tv with surround sound and the latest gaming consoles of choice. As to be expected he also has a refrigerator, electric stove, dishwasher, central air, washer & dryer, and home office complete with computer, printer, wireless internet, Gibson electric guitar, amplifier, and a charging station for all of portable electronics. The lighting in his house has been almost entirely changed to compact fluorescent bulbs. Since Eric travels a lot he doesn’t get to enjoy his home theater as much as he’s like and since he prefers eating take-out his kitchen appliances (other than the fridge) are hardly touched. In addition, the local cleaner happily washes and presses most of his clothes. Eric’s annual electric bill is around $600.

Tommy on the other hand is a father of three: Jimmy (age 12), Johnny (age 8), and Sally (age 4). Tommy’s wife Molly is a homemaker and makes the best chocolate chip cookies in town. Upon entering Tommy’s house, we find many of the very same appliances Eric has, with one major difference – they actually get used!

With three kids to look after, Molly is very busy. Every morning she turns on PBS for Sally and throws in a load of laundry. It’ll be the first of many throughout the day. While Tommy and the boys take showers, she makes breakfast (and later dinner) for the family using some combination of electric and microwave oven. She empties last night’s clean dishwasher load and fills it right back up after breakfast with plates, glasses, coffee cups, utensils and pans. Then Molly runs a vacuum over the house.

Even though the sun is shining in the house’s east windows, almost every lightbulb in the house is on and they’re all incandescent! Jimmy left the bathroom lights on as he hurried out to school (he also left his computer and stereo on). Three of the bedroom closet lights are on. The lights in the family room where Sally enjoys morning cartoons and the twelve canned lights in the kitchen are always on – 24/7.

At 11:00am every morning, the pool pump kicks on. This bad boy runs for 6 hours a day everyday of the year. To make matters worse, it’s 102 degrees outside, so Molly cranks up the AC and leaves it on late into the night since the second floor gets incredibly hot and the family has a terrible time sleeping in such heat.

Can you guess what Tommy’s annual electric bill looks like? Well, I can tell you that if Tommy lives in California his average monthly electric bill is in the $500 – $600 range putting his annual nut at a whopping $6,000 – 7,000!

This financial drag would be bad enough for poor Tommy and his family, except his utility just notified him that they’ll be increasing tariffs next year by 14%. This is the equivalent of adding a thirteenth month to his bill! I hope Tommy gets a pretty hefty raise next year. He’s going to need it.

I wish I could say that I made this story up, but it’s based on the very real differences in power consumption I see every day. Are you more like Eric or Tommy or are you somewhere in the middle? You must answer this question for yourself before buying solar panels from anyone. This self analysis is critical if you’re to get the biggest bang for your solar buck.

In my next post, I’ll help you determine your ‘Energy Profile’ and how your use of energy impacts the cost of going solar.