Solar Power Systems: Does Size Matter? (Part 1)

One of the most common questions potential solar customers ask is, “What size solar power system do I need to offset my electricity bill?” The Reader’s Digest version of the answer is that, from a financial standpoint, you don’t want your solar investment to far outweigh your immediate need. Yet you also don’t want to be short-sighted when it comes to your future energy use.

It’s fairly easy to get an idea of current requirements by reviewing your energy usage over the past few years. There are also some tools you can employ to get a more accurate idea of how you currently use energy, such as having a professional home energy efficiency audit conducted, and adding a Smart Meter that identifies consumption in more detail than a conventional utility meter.

You also will need to consider how you may or may not change the way you utilize electricity in the coming years. Some of the variables that can affect change in energy consumption include:

- Long-term or permanent changes in family size. If you have children heading off to college or out on their own, are just starting a family, or have Grandma or Grandpa coming to live with you, your energy usage could change significantly.

- Appliance upgrades. Swapping out your old, avocado-green appliances for new Energy Star models not only makes them easier on the eyes--it can also dramatically reduce your household energy requirements.

- Creature comforts. Installing central air conditioning systems or hot tubs always serves to increase your energy bills.

- Gettin’ your Prius on. Driving hybrids is great for the environment, but remember that you will need to charge your new car’s batteries in order to reap the benefits to your carbon footprint.

- Home improvements. Making changes to the infrastructure of your home, including installing a programmable thermostat, weatherproofing doors and windows, insulating your hot water heater, replacing single-pane windows with their double- (or even triple-) paned counterparts, mounting an attic fan to drive warm air out in the summer, and adding extra insulation to attics, crawl spaces, and basements, can all add up to big energy savings.

These changes, made incrementally over time, generally don’t provide an immediate huge impact on your energy bill. But down the road, you will definitely notice a significant 5- or 10-year change in consumption—and that sustained change is what you need to consider when configuring your solar energy system.

In my next post, I’ll talk a bit about the different levels of offset you can achieve for your energy bills with a new solar power system. Stay tuned!