Seal building envelope first
With rising energy costs, many homeowners are looking for ways to make their home more energy efficient. Net zero is the ideal, with a home producing as much energy as it uses. It is possible to bring an existing home closer to net zero standards.
I will address building envelope issues first. Your first move should be fixing these issues. Once you have maximized these effective weatherization measures, then it's time to go with technology. If you don't seal the building first, to create a tight envelope, it's the same as walking around in the middle of winter with an unzipped jacket and buying warm pads to stay warm. The logical thing would be to zip your jacket first, or, in this case, sealing the building envelope.
The most effective way to identify problems with your building envelope and other inexpensive solutions prior to going with fancy technologies is to hire a professional home energy rater. Depending on your area, they will have different names, but most likely you will find them listed as HERS raters or as a building analyst with the Building Performance Institute. Also, don't forget to check with your utility company as they might provide incentives to cover the cost of the improvements.
Now, assuming you have addressed the basics, now it's time to find ways to bring your home closer to net zero. You can either go with geothermal or solar. Although these approaches have a big upfront cost, in general, you can recoup your investment in 7-9 years. If you chose to go with a geothermal HVAC system, then it makes sense to go that same route with your water heater. You are using the heat pulled from the earth to heat your water as well. With the solar option, you can install photovoltaic panels, and add solar thermal. The latter option introduces a renewable energy option that you can also couple up with your geothermal system to try to cut your energy usage as much as possible.
If you opt for solar, first check with your utility company to see if they accept net metering. You do not want to store your generated solar power in batteries, it makes the system cost prohibitive. Keep in mind that if you use geothermal, it makes no sense to go with solar thermal for your water heater. You will be spending too much money to accomplish the same goal.
Additional thoughts on adding features to make a home closer to net zero is available here on ProudGreenHome.
Luis Imery Luis Imery, through his business the Imery Group, is a full service construction, home energy performance, green certification and real estate group specializing in infusing sustainability in every facet of the real estate cycle. Its construction division has become pioneers in the Athens, GA area in green building of speculative, custom and design-built construction. Just in 2011 they have over 110 units slated for green certification under the EarthCraft program. www