Energy and Atmosphere is the largest section in the LEED for Homes Rating System, accounting for 28% of the total possible points (see post on LEED for Homes Categories). Critics of the LEED Rating system often argue that it focuses too much on energy efficiency. Personally, I disagree — I think it is probably the most important thing for our climate. According to the LEED Reference Manual, the average certified LEED home uses 30%-40% less electricity and saves more than 100 metric tons of CO2 emissions over its lifetime. Additionally, and perhaps most importantly, almost every investment in this category pays for itself through decreased utility bills–so financially these credits are usually worth the upfront cost.
In the book I am working on, I contend there are only three reasons to go green:
- Financially. Upfront investments lower utility and maintenance bills, saving you money in the long run.
- For your health. Many standard construction materials off-gas and can cause respiratory illness. (This subject is addressed in LEED’s section on indoor air quality.)
- To feel good about it. Anything you can do to go green is better for your family, the environment, and our children’s future.
Energy and Atmosphere fits into category #1, but if you take it further, reducing electricity usage also reduces the burning of fossil fuels, which affects our health…so it really fits into all three categories.
There are two paths in the LEED Rating System: the performance path and the prescriptive path. The performance path requires the use of energy analysis software known as the Home Energy Rating System (HERS). Our green rater, Jimmie Sparks, uses this software. It is an easier path to go down because you get one number that incorporates a rating for the following:
- insulation
- air infiltration
- windows
- heating and cooling equipment
- heating and cooling distribution system
- appliances
- renewable energy
Then, that leaves just 3 other areas to address:
- hot water distribution system
- hot water pipe insulation
- residential refrigerant management
If you go the prescriptive path, each one of these is its own sub-section (so there are ten, instead of three + the HERS rating). We are planning on going down the performance path, because we already got our HERS rating, and it is easier. But I am curious as to whether we would end up with the same number of points if we went down the prescriptive path. And, for the purposes of this blog, it is good to address each of these sub-sections, since they all represent very significant choices we made in the building process. So, I will go through it both ways and see how we come out in the end.