Thursday, October 30, 2008

Energy rating test for our house

A report mainly for myself...

This morning we had the energy rating done for our house. The Alaska Housing Finance Corporation (AHFC, at has a Home Energy Rebate Program where they reimburse some costs of improvements done to a house. First, an energy rating has to be done for the as-is conditions. So that's what we had done. Considering that on the radio, they said that AHFC was trying to train more testers because there was a long waiting list, our 2-3 week wait was relatively short. The rating cost $500, of which $325 will be reimbursed by AHFC.

The technician got a feel for the house, asked about our electricity and heating oil usage, measured the sizes of doors and windows and estimated the insulation below our house (since it sits on pilings) and the insulation in the roof. Then he hooked up a door frame made out of tubing and thick fabric, with a hole in the center for a fan, and did the actual blow test. Everything that circulates air was turned off for the test: mainly oil monitors in our case. During the test, the fan sitting in the improvised doorframe blows air out of the house, so that the air in the house is below ambient (outside) air pressure, and an instrument measures how fast air leaks back in from the outside.

With the testing parameters, the air in our house would be exchanged 4.5x per hour just due to the leaks in various places. This apparently corresponds to 0.3x under normal conditions: I assume that means that within 3 hours, all of the air is effectively circulated to the outside, or that the house would cool down considerably within 3 hours. Since we don't have an air handling system, there should be some leakage of air, but not as much as we had - may be around a value of 3.5 instead of the 4.5.

View of our entryway. The main door is wide open. In its place is the temporary fabric door, red in color, with a fan, almost ready for the blow test.

After the blow test and some notes, the technician connected the fan one more time, to underpressurize the house again. And then we went around, using our hands to feel for cold spots, where the cold outside air (0 F or about -15 C) was seeping in. That was rather interesting. In the original log-house, some of the windows do not have as much insulation above or below them as others, and a couple of them we will definitely insulate better. One window, which does not close (since our house is a bit tilted) was ok. Our bedroom door is a major problem - it was even singing from the air flowing into the underpressurized house. And, one area that I did not expect that had a lot of air leakage, were the corners where the addition that was put in later met the original log house. Where the logs were originally outside (but now are inside), they were not chinked, there is no squish-able insulation between the logs, they just sit one on top of the other, and are very drafty.

Chink these logs!

Insulate above the windowframe!

Interestingly enough, an arctic entry was not suggested. What was strongly suggested as cost-effective measures to reduce heating costs were installation of better doors, and caulk and seal the holes in between the logs. Also, as secondary measures, the technician suggested an on-demand water heater that would also run on the #1 heating oil we use for heating (instead of the traditional big water heater); installing a passive wall vent (making a hole for air intake for the wood stove so that the wood stove does not create a draft in the house); installing new bathroom fan or rangehood; and replacing refrigerator as needed.

Overall, we have a 3 star plus rating, 77 points. Three-star-plus is higher than 3-star but below 4-star.

I am glad we got the rating done. It was eye-opening.


Matt Heavner said...

We love our hot water on demand. Good job on the energy check!! We are on the waiting list, hoping for the inspector to call.

Carrie said...

We are finally getting our house tested tomorrow. I'm very interested in what they say! It was fun to read about your inspection.