Friday, September 24, 2010
What are the Two Types of Energy Codes?
The construction industry is starting to introduce and enforce more energy codes that architects, engineers, manufacturers of building products, lighting designers, and others to follow. The energy codes affect how we build homes and our commercial buildings.
There are two types of energy codes. One is “Prescriptive” and the other if “Performance.”
What is a Prescriptive Code?
Prescriptive codes are the ones that tell you exactly what you can or cannot use in certain parts of the building. When you have a cold and you go to the doctor, the doctor prescribes a pill for you to take to give your body at least the minimum level of chemicals that will make your fever go down, your head and throat aches to go away, and whatever else the pill is supposed to do for you. This is similar how the people who wrote, adopted, and are enforcing the energy codes (like the doctor) are prescribing the minimum levels of “R values in the walls and windows (an “R value” is a measure of thermal resistance. The higher the "R-value" the lesser amount of heat will be allowed through itself), lights with certain “watt per square foot” values and so on.
The prescriptive codes are being used in a growing number of states throughout America. Your designer should find out if they are supposed to comply with any of them. The Department of Energy created free software that anyone can download that will prescribe what energy saving properties must be in homes.
For residential construction, they created "ResCheck"
For commercial construction, they created "ComCheck".
Since every state has their own weather patterns, there are different prescriptions for each state. So, download the software for the state that applies to your project. These codes affect the remodeling of an existing space, addition to a building, and new construction.
In 2012, the Department of Energy will make their prescriptions even stricter. They intend to include the energy that plugged in appliances give out to the space and other things. This will give us new incentives to keep the owner’s manuals of all our electrical gadgets.
What is a Performance Code?
Performance codes give the expected outcome of an overall design of a space or building but do not prescribe exactly what values the walls, ceilings, roofs, floors, and window need to have. Its kinda like if you went to a Naturopathic Doctor when you have a cold and they recommend that you purchase certain salts, herbal teas, powders, candles that are suppose to perform different healing miracles that has not necessarily been tested in the laboratory and documented to match exactly what you will purchase and use.
Performance codes give the designer a lot more room for creativity. But, it can be a lot more expensive because newly designed building systems will need to be built and tested in laboratories to obtain some energy value. Then, after the building systems meets the performance codes, they might be audited again after the real building is put together to see if it maintains it performance codes parameters with people and equipment working and living in them. If they do not comply, then the owners might be required to spend more time and money to remedy the deficiencies.
Due to time and money restraints, we will find that most buildings will be designed while using the Prescriptive codes instead of the Performance codes.
We will discuss who are writing these codes (what gives them the authority), if they are being adopted by all states and communities, and if the codes are being interpreted and enforced equally in all areas of the country during this coming podcast on Monday, Sept 27th, 2010 at 5:30 pm EST. Can't join us at that time? No problem. Just click here at "The Best Architecture Show Ever" and download the podcast onto iTunes by clicking on the iTunes icon while at that website.
Check out our discussion of LEED certification (prescription code) results on lighting and HVAC in my book "The Designed Office"
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