Solar Retrofit 2007
Once the house was completely enclosed, Alva Morrison, a local Energy Rater, came over and did a blower door test. We sealed up the house, closing all the windows and exterior doors. We left the interior doors open so air could move freely.
Alva then sealed up the kitchen door. See the photos below. This is a piece of canvas that makes the door airtight. There is a fan at the bottom that draws air to the outside. When it was turned on, we walked around the house to all the places we thought air would be leaking in. I found one particularly bad spot around an old window in my bedroom. There were insignificant leaks around the access panels to the attic space. Places I expected leaks were ok, and I found leaks where I did not expect them, so it was very informative.
INSIDE:
OUTSIDE:
Before getting to this point, Alva had determined the volume of the interior of the house. If you look to the right of the top photo, you will see a gizmo on the door that records the amount of air being moved by the fan. This information is input directly into his laptop, where he has data about the construction of the house. With this combined data, the computer modeling program tells Alva how much air is moving out of the house and what sort of upgrades the house can use to lessen that movement.
The subsequent rating is based on the International Energy Conservation Code, which is 100. My rating came in at 88, meaning my house is 12% more efficient than the code. The lower your number, the more efficient your home is.
Here are Alva's comments about my test, rating and recommendations:
"Nan’s house is a great example of what can be done to turn a pretty average house, built to code a couple of decades ago, into a modern energy-efficient home. If built as is today, it would exceed qualification for the USEPA Energy Star certification, even though many of the walls still have 2x4 insulation in a 2x6 wall. The main factor driving the house’s lean performance is a thick blanket of attic insulation. But the solar hot water and the balmy sunroom with a thick adobe wall to catch and hold the heat provide solid backing. Add to that a refrigerator which squeezes kilowatts until they scream, and you have a working person’s house to take us all through the next century of global warming both economically and comfortably. All these things were added to the house by Nan at moderate expense.
"Analyzing possible improvements was very interesting. Tearing off sheetrock and re-insulating the walls seemed like it should be a no-brainer. But when we ran it through the computer, it only showed a savings of around $25 a year- not much reward for all that trouble. The moral is, heat goes up, not sideways.
"However, we found another weaker spot in the building’s “heating envelope”: the uninsulated foundation. A quick rework of the house through the energy rating software showed that digging a barrier of four inch rigid foam in around the perimeter of the foundation would return $175 a year - and that’s if the cost of wood and gas stays the same (don’t hold your breath for that!). Get out your shovel, Nan!"
Very funny, Alva!
Once you have an energy rating, you can take that data to a mortgage broker and get an energy efficient mortgage (EEM) to pay for the upgrades. The premise behind an EEM is that you will pay for the upgrades, but you must be able to save at least double the monthly cost in energy bills. If you're mortgage goes up $25, you will have to be able to save at least $50 on your energy bills. A blower door test, an energy rating, and an EEM all go hand-in-hand.
You may also be eligible for a rebate from your local utilities. PNM, here in New Mexico, is giving 25% rebates on blower door tests and any kind of weatherization you do to your home. There may also be tax credits. Check with your accountant.
Please feel free to contact me or Alva for more information. My contact information is at the top of the page. Alva's email is alvamorrison@gmail.com, and his phone number is 505.579.4136.
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