The core concept in the Zero Net home
is to produce as much energy on-site as your home consumes in a year. For a typical home that is about 11,000 kWh's for electricity and 110 million BTU's for heating, the equivalent of about 19 barrels of oil (PDF)
. In order to even get close to achieving this type of energy production, you will have to do things -- get solar panels and radically reduce your heating and cooling load.
To date, there have been two significant set backs for solar -- up-front cost of installation and aesthetics. A standard 3 kW system can cost upwards of $24,000 (not including rebates) and though some find them attractive, many people do not like the techie look of solar panels on their otherwise traditional looking homes. An additional problem is that in order to get to Zero Net, your home will also need a "cool roof" to reduce the amount of heat that enters your home during the summer. Normal solar panels give you energy production, but they don't do much for reflecting away the summer heat.
A new innovative solar product manages to solve all 3 problems, for about 1/2 the price of a typical solar installation, according to manufacturer Redwood Renewables. Redwood's solar tile shingle made it to the finals of the California Cleantech Open (often referred to as the Oscar's of the cleantech world). Here's why. The tiles look just like regular slate-colored roof shingles, and they cleverly solve the aesthetic challenge by creating "dummy (non-PV) tiles" which match the solar tiles in color, size and texture. So you can place the solar tiles exactly where they need to go without disrupting the uniform look of your roof, and (you guessed it) the dummy tiles act as a "cool roof" surface, reflecting away summer heat.
There are many BPIV's on the market (building-integrated photovoltaics) that are designed to enhance the look of a traditional home, but this is the first one I've seen that incorporate the matching non-PV tiles and gives them reflective, cool roof properties. The manufacturer claims to be able to deliver a 6 kW system (enough to power both your home and a plug-in electric car) for about 50% of the costs of a normal solar installation. How? For starters you can qualify for both cool roof and solar rebates. But the big cost savings comes in installation. Normal solar panels are heavy and require brackets and complex wiring (about 200 holes drilled through your roof in a normal installation). The shingles, instead are very lightweight, require no brackets, and like christmas lights they are wired together so there is only a single hole drilled through the roof.
The other thing I find quite remarkable about the product is that it is made of recycled waste polymers that are de-vulcanized, meaning that at the end of their life cycle, they can be recycled and made into new shingles. You can read more by visiting the Redwood Renewables site