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. 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:

“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

Once the infrastructure decisions were finalized, Alex, the construction contractor, and I could firm up our plans. We knew where water and gas lines could go in the house and greenhouse.

Not only did I plan on the greenhouse addition, but I also made some drastic changes in the rest of the house.

1) I replaced all my single pane windows and sliding glass door with vinyl, double pane, energy efficient, low-e windows.

It’s important to choose the right windows for different areas of a home. Lighting, vies and orientation are taken into consideration.

There are several criteria to determine a window’s performance, two of which are:

• Solar Heat Gain Coefficient (SHGC) – the higher the number, the more heat the window transmits.
• U-factor rating of the National Fenestration Rating Council (NFRC) – the lower the number, the more efficient the window, based on the glass, frame and spacer material.

I have big pictures windows and a slider on the northeast side facing the mountains. Sun pours in here on summer mornings, so I chose windows with a low SHGC that let in sun and but heat. Obviously, on the southwest side, that’s not what I wanted, so I chose windows with a high SHGC that allowed the sun to heat the space.

Low-e stands for low-emissivity. There is an invisible, thin coating on the glass that controls the amount of heat moving through it and affects the SHGC and the U-factor. All windows should be labeled with this information.

2) I changed the floor plan in western 2/3 of the house to facilitate heating, which was difficult due to a remodel done by a previous owner. The traffic flow was choppy, which also prevented heat from being distributed evenly. I was spot-heating separate areas, which was a continual experiment and not very effective. If I could easily get the rooms heated, I would further reduce my energy bills.

3) I created two separate heating zones:

• The greenhouse, girls bedrooms, a bathroom
• The kitchen/living room, my room, a bathroom

Do you remember that huge room where I installed that huge sunny window previously? I split it in two and gave the girls identical rooms. The doors, which I recycled from other parts of the house, opened into the greenhouse, which would help heat them and the second bathroom. This area was separated from the kitchen/living area by a steel exterior door.

4) I added insulation in the ceiling over the kitchen/living part of the house. Since we put gas lines in the attic and access panels in the ceiling, we got a chance to look at the insulation. It was pretty thin, and we had disturbed a lot of it with our work. I decided to beef it up by having R30 shredded fiberglass blown in on top of what we guessed to be about R19 insulation. I was eager to see how my heating bills would react.

My original thought for the greenhouse was to create a 5.5′ wide passive solar hallway to the girls’ new rooms and bathroom. This would span the entire front of the space. After many measurements and number crunching, we decided to fill the entire corner with the greenhouse. It would be easier for Alex to build if we brought the exterior wall out even with the existing wall. This space was 8.5′ wide and allowed the planting bed to be included.

Once we had these dimensions, we could create a detailed design and start ordering materials.

More on energy efficient windows:

http://www.energysavers.gov/your_home/windows_doors_skylights/index.cfm/mytopic=13320

I will spare you the entire thought and building processes and show you what we finally decided on.

Since this is southwest orientation, my main concern was getting extra light and heat, since the winter sun does not come around to that side until late morning. I put three fixed skylights along the lowest part of the ceiling, which has worked well. The sun comes through them a few hours before it gets to the front.

In the New Hampshire house, the south facing windows were floor-to-ceiling. I wanted as much sun coming in as possible for daytime heating. Here in Taos, I wanted a planting bed close to the windows for maximum light, so the windows are in the 5′ space above the 3′ deep planting bed. In both instances there is a 1′ spacer between them for support.

Ventilation is as important as heating. Plants and people don’t like temperatures that are too hot, as much as they don’t like them cold. To keep everyone and everything comfortable, I installed:

• A glass door flanked by two double-hung windows. This allows more sun in winter and serves double duty to ventilate in summer.
• Two double-hung windows in the end wall
• Two VeluxR operable skylights in the upper part of the ceiling. This is where heat will rise, which made it the most logical place for a moveable vent. Air moves in through the windows carrying the heat out of the top vents. Moving air is cool air, so opening the windows and the vents cools off the greenhouse, even if it is hot outside.

The soil in the bed is to be part of the thermal mass. It will absorb the sun’s heat to keep the temperature levels even and keep the plants warm. The concrete floor and an adobe-lined wall on the northern side are also mass that will absorb sun and ambient heat to radiate back out at night.?

The ceiling is super insulated, and exterior doors lead into the four rooms of the house. There is no supplemental heat in the greenhouse. In the event there are many cloudy days in a row or old-timey winter temperatures of 40 below, I will sacrifice the plants as the greenhouse gets cold, but the heat in the other rooms will not be lost. The girls have small gas heaters in their rooms for the coldest days and nights.

The work was done enough by Thanksgiving to start seeing the benefits. My fuel bills that following winter were half of what I’d been used to paying. I cut my wood consumption by half with the new ceiling insulation and double pane windows, and my natural gas bill was about $40 a month at it’s peak with the girls using their heaters.

Come spring, I got an energy audit and a surprisingly good HERS (Home Energy Rating System) score.?

After graduating from UNH, I worked on a couple of vegetable farms and a u-pick fruit farm and did some landscaping. What I really wanted to do, though, was build solar greenhouses. I called a local company that retrofitted them onto existing homes. The owner was excited about my enthusiasm. Remember, this was the early 80s, solar was not an everyday word yet, and not many women were carpenters.

In our initial phone call, he asked if I had any carpentry experience, or if I at least knew the terminology. Although I’d wanted to be an architect my whole life, I didn’t have the knowledge he needed. He suggested I work in a cabinet shop for six months to a year to learn carpentry basics. He recommended a shop to me, where I got a job right away. I was excited to get started on this new path!

I built cabinet doors for several months. I played with pine, oak, cherry, maple and birch studying their grains and the differences in how they looked and felt, how each acted with a saw and a sander, and how each responded to stain and varnish. It was quite an education, and I loved it!

I spent a lot of my day sanding those beautiful raw woods. The orbital sander was my pal. I came home covered in and throughout with sawdust every night. It was exhausting, physical work, and the conditions were far from ideal, but I never lost sight of my plan to build solar greenhouses.

After six months of radial arm saws, table saws, circular saws and joiners, the lesson I learned was that I didn’t like power tools. The orbital sander remained my friend, but the rest were bigger and scarier than me.?

There went my carpentry career!

When I left the cabinet shop, I took my newly acquired knowledge of building, terminology and woods along with the few hand tools I had to buy. Little did I know the following year would bring me my first energy efficient remodel.

At the University of New Hampshire, my Soils Science teacher, Art LeClair, turned me on to solar energy. He was my favorite teacher – enthusiastic, intelligent, knowledgeable, experimental, fun and funny. I naturally absorbed what he conveyed.

On a winter field trip, our Soils class visited Solar Survival in Harrisville, NH. This was the home and lab of Leandre and Gretchen Poisson, authors of ‘Solar Gardening: Growing Vegetables Year-Round the American Intensive Way.’ They grew food all winter in frigid, frozen, snowed-in northern New England using solar pods, which they developed.

A solar pod is a 4′x8′ cold frame surrounded on the outside with rigid foam insulation and buried partially in the ground. The lid is not a piece of glass or an old window, like a typical cold frame. It is an arch of two layers of KalwallR greenhouse glazing with Angel Hair, a fine and translucent, yet heavy duty, insulation, sandwiched in between.

The thermal mass inside the pod is a black 55-gallon drum filled with water and laid on its side at the north end. During the day, the water absorbs the sun’s heat and slowly radiates it back out over night.

This photo is a series of pods lined up end to end. You can see the drum laying on its side at the far end of the front pod.

The translucence of the insulation is key. It must transmit enough solar energy in low-light winter for healthy plant growth and to warm the water in the drum to a high enough temperature that it can radiate heat on a cold New Hampshire night.

My friend, Hugh, and I partnered up in lab to build a solar pod. We didn’t get to grow anything in it, but witnessing that process at Solar Survival was proof enough that it worked. After that field trip and construction project, I was completely sold on solar energy!

Art shared another source of information with us, a book by Rick Fisher and Bill Yanda of Zomeworks in Santa Fe, New Mexico, called ‘The Food and Heat Producing Solar Greenhouse.’ It was published in 1980 and already out of print the following year. Solar hadn’t caught on yet, so I guess it was not deemed an important book. I tracked down a copy, though (remember, this was way before Amazon and used books!), and studied it as though I was having an exam on it. I now have a dog-eared copy, which I repeatedly refer to, because, like I said last week, solar principles never change.

After that semester at UNH, my love for solar construction and New Mexico was burgeoning.

(Glazing and insulation materials to build Poisson’s solar pod and solar cones are available from Solar Components, www.solar-components.com/sun.html)