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.?

When I bought my house, it was an upside-down T, with the stem facing southwest. In last week’s post, I talked about installing sunny windows in the southeast and southwest walls for passive solar daytime heating. Now I was trying to decide how to further remodel for more solar gain.

I could have added a greenhouse on the southeast corner adjacent to the kitchen. This was very appealing as far as harvesting food and herbs. I’d also envisioned it as a sitting area, the breakfast nook, I suppose. But I enjoyed the new windows, and one was in my bedroom. I’d have missed that if it went into a greenhouse instead of to the moon, trees and coyotes.

The warmest winter sun hit the southwest corner, so I decided to add something there. I wasn’t sure what, but many pencils and eraser goobers later, I came up with this plan. Craig Simmons of Eco Builders fleshed out the details for me.

I was content enough with the heat produced through the new windows that I put these drawings away. I was also a working single mom of two young girls, and my time constraints prevented me from doing a lot of research into this project, never mind starting and completing it! I rolled up the drawings and propped them up on my desk.

In 1997, I lived in an old block home on an irrigated acre of land in Ojo Caliente – almost the adobe dream home! I was more interested in the land than the house, and we cultivated half of it with beans, corn, tomatoes, squash, herbs and flowers that we sold to friends and co-workers.

Out near the garden, there was a small frame greenhouse with translucent polycarbonate walls. I checked the overnight temperature in early spring to see if I could start my seeds in it. It was too cold, since it was not heated or insulated. It was essentially a cold frame with an 8-foot ceiling and roof.

I started researching greenhouses and was disappointed to find all standard greenhouses need supplemental heat. This is usually generated with electric heaters for something as small as I was looking at. Aside from growing food to eat healthy, cost needs to be taken into consideration. Heating a non-insulated building of plastic walls with electricity was not cost-effective.

I came across the Growing DomeR Greenhouse in a gardening magazine. It is still available, and I see them popping up across the landscape as food and energy costs rise. This is a passive solar, geodesic design with glazing on the south side and insulated solid walls on the north side. Planting beds and the concrete slab floor are the thermal mass, along with a pond. Do you remember the 55-gallon drums in the solar pods? Poisson knew water is one of the best materials for thermal mass. It must be sized properly so it can radiate heat effectively. The pond can hold fish or water plants, or boards can be placed across it to make more room for container plants.

The combination of masses in this greenhouse meant no supplemental heat. It was an environment that took care of itself – an ecosystem of sorts. I was sold on it immediately!

For a variety of reasons, though, I didn’t purchase one at the time, but this is the only greenhouse I recommend to anyone. It needs no extra heat, and the larger ones double as a small living space as well.

Ten years later, it is spring 2007, and I want to start my vegetables from seed. I am toying with the idea of buying a 12′ diameter dome greenhouse and putting it about 100′ from the house down the hill on my property. This is a sweet, quiet, sunny spot with completely different views and feel than the house. A few cottonwoods along the irrigation ditch give the space a cozy feel and summer shade. A passive solar greenhouse here would be an excellent get-away.

As I walked the land, I began to picture it. I imagined bringing in electricity and water, and building a path of crusher fines between the greenhouse, the house and the garden. I considered views, sun, neighbors and the heat the greenhouse would produce. I wanted to somehow move the extra heat back up to the house in winter. I thought of underground ductwork, insulation, fans….. My little greenhouse project was getting complicated, the kind a contractor would balk at.

In a split second, like the cartoon cliche of a light bulb going off over your head, my face went from bewilderment to wonderment and glee! I decided to build an attached passive solar greenhouse for heat and food. Remember the mention of this book??

I dusted off my original vision and the drawings Craig and I had worked on a few years before.

More info about:

Growing DomeR Greenhouse http://www.geodesic-greenhouse-kits.com/

Craig Simmons, Eco Builders http://www.ecobuilderstaos.com/

When everyone moves to Taos, they want to buy an old adobe home on an acre of irrigated land. I was no different. I searched for a house for three years. Some homes were perfect, but just out of my price range, some transactions fell through, and the perfect three-acre piece of land needed an expensive 1/4 mile long driveway through a swamp.

I stumbled across my current home in the newspaper in December 1998. It was nothing what I was looking for – 1800 sq ft of frame ranch on .87 acres of sagebrush – but it had three bedrooms, two bathrooms, a studio space and incredible mountain views. The biggest selling points, though, were the two covered porches (north and south) and the established flower gardens, strawberry patch and apple tree. It was in my price range, and the transaction did not fall through, so it was mine in January of 1999.

Do you remember my advice from last week? Don’t move in until the work is done! I hadn’t forgotten, so I shelled out one more months’ rent and upgraded my new home from afar.

I painted the walls with BioShield natural paint. I bought five gallon buckets of white and tinted them. The price was comparable to five gallons of toxic paint, so money could not keep me from creating a healthy home. I replaced the dark brown, cat-smelly carpet in the living room and bedroom with an oak Upofloor brand floating floor with a non-toxic finish.

While the contractors and I beautified my new digs, I watched the winter sun.

My observations showed that the winter sun drenched windowless walls. I was so in love with the porches, gardens and views that I hadn’t noticed! Common to Taos, picture windows face north and northeast to the mountain views. Very beautiful, but very cold! I knew then that my next project would be installing windows on the sunny side.

The house was oriented SE to SW, with the sunny side facing southwest. In a perfect solar world, a home should have an east-west orientation with the long wall facing south. This collects the most sun for maximum heat collection. You can have a variation of 15 degrees from true south, but up to 45 is acceptable. My orientation was ‘acceptable.’

That summer, I found a local warehouse of hundreds of wood windows recycled from a company that had gone out of business. I had measured my interior walls for available space and chose windows as close to the maximum size as possible.

In early October, just in time for winter, my new southwest facing windows were installed! While we had the walls open, we beefed up the insulation where it was thinning and sagging.

Over the following winter, I continued to watch the sun bathe the house inside and out.

The huge room my daughters shared was a two-car garage now enclosed in a previous remodel. The sunny side was mostly blank wall with two narrow windows across the top. I hired a builder friend to put in a glass door, and a large window on one side and a trombe wall on the other side.

A trombe wall is a window installed over a wall of thermal mass (concrete, adobe, water). Vents into the house are placed at top and bottom. As the sun heats the wall, warm air moves into the house through the top vent, and cooler air replaces it to be heated and moved back inside via convection currents.It is an effective way to use solar energy without having the sun directly in the house, if you don’t want to place a window to unwanted views, or if you want privacy.

The large window materialized, and the trombe wall did not (long, irrelevant story), but the solar energy I did harvest warmed the room during the day. It also hit the concrete slab and radiated a bit at night. This was not high-tech, but it served its purpose to cut the daytime heating down for that dark room.

Meanwhile, I observed the sun for several years. Plans for a major remodel percolated slowly and deliciously like fine coffee, and my restless, latent architect went to work with pencil, eraser and graph paper.

(Click for more information on trombe walls, Bioshield paint and Upofloor.)