What exactly does that rater do?

One of the keys to following a green building program is the third party testing and verification. These guys are called "raters" and in some programs "verifyers". I was lucky enough to get one locally that was HERS and NAHB certified. His name was Joe Gilmore. Great guy who helped me out a lot. Lots of people ask me how this sort of process works, and what goes on. I'll try to fill you in by telling what happened on my job. First, Joe took my plans and specs and used that information to build an "energy model" of my residence. The model takes into account all of the exterior envelope of the structure in relation to its surroundings. So you have the physical shape of the home, the normal operating temps inside, the average temps outside, the relative position and arc of the sun, and prevailing winds etc. Also included are the r-ratings of the surfaces, the walls, the roof, the flooring, and how much heat they transfer over time. Also you put in the locations and sizes of the windows, and the heat loss characteristics that are on the label from the manufacturer. Next then program accept values for overhangs and porches and their locations. Then we put in the internal loads, people, pets, tvs, appliances, etc. The output from the program can be used to tell you the loads on the building and how well it will perform. If you change the r-factor of components by changing the amount of insulation or the number of windows, the load on the structure changes also. It's a great design tool, because now you can get the feel for what upgrades get the best bang for the buck. Just by rotating my home 90 degrees and moving the western exposure from eleven windows to two had a huge impact on the amount of energy I'd save. Later during construction, the rater returns to inspect the air sealing of the shell and installation of the insulation. At this time we tested all of the ductwork that would be covered up for leaks. At the end of construction we test again for tightness of the envelope, final test of the HVAC systems, and if your rater is your verifyer also, he can affirm that you used all of the products required to get your points. Raters are the key to telling you how well your choices will perform, and helping you spend your green dollars in the right places. And they have the equipment to see things that will not be seen otherwise.