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The Grande Finale – an Energy Audit & HERS Score

October 26th, 2009
Written by Nan Fischer

My friend, Alva Morrison, has been in the weatherization industry for many years, working for the state of NM helping families in need tighten up their homes with insulation, caulking and funding. As energy audits got popular for the general public, his natural next step was to become an Energy Rater. Special training and equipment is needed for this job, which entails sealing up a house, running air through it, analyzing air leakage through computer software and offering recommendations.

When my construction was done, Alva and I decided to do an energy audit. Instead of guesswork, I wanted documentation of my energy savings were and how I could make improvements to further save.

A blower door test determines energy usage. Alva determined the volume of the house, then we talked about construction details. He plugged that information into his software, then we sealed up the windows and exterior doors, leaving the interior doors open for maximum air flow.

He installed the blower in the kitchen door. blower door_3631 The red canvas was sealed all the way around to make the door air-tight. The blower was plugged into his laptop, then turned on to create air movement, which was registered in the software. We looked for areas where air was coming in. Alva caulked a few old window frames, and rechecked the figures.

We were surprised at some of the results and recommendations. Here are his comments:

generic viagra “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 2×4 insulation in a 2×6 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!”

As you can see, an energy audit gives you a lot of information on how to improve your home. I had him calculate a HERS (Home Energy Rating System) score, because I wanted to be able to show others the entire process.

The number of a HERS score is based on the International Energy Conservation Code (IECC), which is 100. My score was 88, meaning my house is 12% more efficient than the code. The lower your number, the more efficient your home is. When I make improvements, Alva can plug that information into his software, re-analyze the results and give me new recommendations

Many municipalities, including Taos, are beginning to require HERS scores on new construction. I highly recommend an audit, and, speaking as a RealtorR, I use them as effective marketing tools for homes. Buyers can see current efficiency and how it can be improved. There are fewer surprises and disappointments after purchase.

Food has been coming out of the greenhouse year-round. Due to some unanticipated condensation problems and failing flashing around one skylight, the greenhouse is not in full use. There is no soil in the bed yet, but I have been successfully growing in containers. This picture is my tomato garden on Jan 31, 2009. Once the construction issues are resolved, I will have achieved my goal of a true food-and-heat-producing solar greenhouse.

Find a certified local Energy Rater through RESNET – Residential Services Energy Network http://www.resnet.us

The entire remodel with more details and pictures is on my website: Solar Retrofit 2007 http://www.nanfischer.com/remodel1.html

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