Gottfried Green

In Category 1: Energy, the FGBC offers 2 points for each HERS Index point below 100. I scored an 88 as my HERS Index which means I receive 24 points on the FGBC checklist in the Energy category 100-88=12 and 12x2=24 points.

Labels: Cat1Energy, FGBCchecklist, HERSindex

I spoke with Calcs Plus who did the HERS rating on the house. I wanted to know a little more about what I could have done to receive a better index. One of the main hits was taken in having the ac duct work under the house and not within the envelop. This is energy efficiency 101 because with the ac ducts outside the insulated envelop the conditioned air in the ducts is exposed to fluctuating outside air temps. In my defense I have the ducts wrapped with insulation on the outside so they are not completely vulnerable. Also, the tankless water heater uses too much electricity. I chose tankless, on demand hot water because I thought it was more efficient than the traditional hot water storage tanks. Instead of heating water 24/7 in the storage tank with a tankless you only heat the water as needed and therefore use less electricity. The problem is that the intensity of electric needed per use turns out to be higher; at least in the tankless unit I have.

Labels: HERSindex, tankless

The energy rater had estimated the house should score around 80 and in fact the house come in at 88 which is not very good. I am going to have an energy modeling done to see where I could have improved on some of my decisions. It has to be said, however, that I did the best I could working with subs etc. who had only vaguely heard of green building and had no interest in it beyond that. Energy modeling allows you to run hypothetical scenarios into the Energy Gauge software and see how your results come out differently based on changes you make. For example, my spray foam insulation only had a R value of 15 vs. the desirable R19. This I can't change of course but it will be helpful to see where I could have improved. In my reading I thought it did have the R19 value... so I'll learn more on that later. As for the FGBC checklist, with a HERS rating of 88 I will receive 24 out of the 74 maximum points for the energy category.

Labels: FGBCchecklist, HERSindex

FGBC uses a whole house energy performance rating called the HERS (Home Energy Rating) Index vs. an exhaustive list of energy saving alternatives. The energy rater just left this morning and it looks like the house will score ok. The list above shows what's involved in the rating. It takes into account not just heating and cooling and water heating but also, lighting, appliances etc. I receive the HERS score in 4 weeks.

Labels: FGBCchecklist, HERSindex