Eco Building

The Drawbacks of Angled Windows in Passive Solar Building

by nan on 2011/11/07 · 1 comment

A friend of mine is adding a solar greenhouse to a long south wall of his house. He was toying with the idea of angling the windows to catch the winter sun more directly. I told him not to. Here’s why.

Angled windows, yes, do catch the low angle of the winter sun very well. But they also allow the captured heat to escape. Heat rises, and the window is an upper surface, not unlike a ceiling. Heat rises and goes out the window. (photo: flickr jessicareeder)

In summer, angled windows catch unwanted sun and heat up the house, which calls for more cooling and unnecessary energy spent. Shade cloth does not block enough sun to warrant angled windows. (photo: flickr stereogab)

I have never had a problem with heat loss and overheating with windows placed in a straight wall. If the windows face due south and have an overhang, the high angle of the summer sun will not reach inside. Winter sun shines in easily. This is the basis of good passive solar design. (photo: Wikipedia)

A few years ago, I was in a small earthship style home that was originally built with angled windows. The owner said it was 85˚ indoors late at night in winter! There was too much heat absorbed in the thermal mass. Overkill. The owner rebuilt the wall with straight windows and lived much more comfortably after that.

I hope my friend heeds my advice, especially since he is planning on running ducts below his planting beds. He wants to circulate the heated air under the soil while sun beats down on his plants year round. I say more overkill, but I’ll keep you posted on this project!

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Are Earthship Tires Toxic?

by nan on 2011/08/23 · 0 comments

Living in Taos, New Mexico, the birthplace of the Earthship, I frequently get asked about earthships. They are an ‘oddity’, not seen in most parts of the country, so when people come here to visit, they always have to make a stop at Earthship Biotecture at the Greater World community.

When people ask, I explain how earthships are self-contained:

> Solar PV and wind turbines provide electricity, which is stored in a battery bank.
> Rainwater is caught from the roof, collected in underground cisterns and filtered for washing and consumption. Grey water from the kitchen and shower is recycled and filtered again to water interior gardens and flush the toilet.
> Sewage (black water) is contained, treated and recycled to water exterior gardens.
> Planting beds provide food, filter water and oxygenate the air. photo flickr theregeneration

The questions of construction come up next. The crux of the earthship is the used car tire. Tires are laid out like brickwork row by row on the north side and packed with earth. They become the thermal mass for passive solar heating and cooling. In winter, the tire walls absorb the sun that streams in through the south facing glass, hold the heat, and release it slowing and evenly after dark. In summer, they absorb ambient heat and hold it.

When I explain this, the first remark is, ‘Do the tires off-gas? That’s probably toxic!’

This is an understandable concern. I am very sensitive to petroleum products. I gag when I have to buy new tires or get a flat repaired. The smell of all those new tires on display racks makes my throat tingle, and my asthma starts to act up. I react the same way around motor oil, WD40 and even gasoline. Good thing I never wanted to be a mechanic! If you have ever been to a landfill full of tires, that same smell emanates from old tires.

I have never been in an earthship that smelled like tires or gave me an allergic reaction, so from personal experience, I always told people that I was not bothered. If anyone is going to have a negative reaction, it would be me! photo flickr marvins_dad

Out of my own curiosity, I decided to look up the actual answer to this basic question. Earthship Biotecture calls off-gassing a ‘non-issue’. An extensive study by the University of Wisconsin-Madison determined that ‘Tires are hazardous in piles, not Earthships.’ The leaching of hazardous pollutants is minimal. Quite the contrary, they absorb toxic chemicals and are not a potential water table polluter.

An engineer in Alamosa, Colorado, an hour north of Taos, says that tires will break down into toxic, carcinogenic vapors when exposed to ‘high temperature, exposure to light, or the presence of strong oxidizing chemicals.’ When a tire is inside an Earthship wall, encased in stucco and not exposed, it is less toxic that when it is breaking down in a landfill.

Using tires in Earthships is a huge benefit to the environment.

> First, tires are kept out of landfills. The volume of tire waste takes up an unthinkable amount of room, and as they sit in the sun, they release carcinogenic vapors. By using tires in Earthships, landfill space and toxins are not issues, and the tires become inert.

> Tires as walls are the heating and cooling thermal mass of an Earthship.

> An Earthship helps the environment by recycling this potentially toxic product into a building material that eliminates the need for wood, which saves tree, and saves energy through heating and cooling.

Tires are a win/win for the environment!

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Facebook Pages for This Blog

by nan on 2011/08/15 · 0 comments

I’ve had a long history with the Facebook Fan Page. Taos, New Mexico Green Homes was born to promote this blog, green building and my real estate practice. No longer in real estate, I closed it in the beginning of the year.

For months, I have vacillated about starting one specifically for desert verde, always thinking I will stop blogging. I guess we all ponder closing up our blogs now and then. I have decided to stick with it for a variety of reasons, too lengthy and irrelevant to bore you with here.

There are two fan pages now:

> desert verde for green building, green living, gardening, farming, climate change, the environment, ecology and so on. I’ll also post other pertinent info you might want to read and share.

> Journal Inspirations for journaling prompts, writing exercises, discussion and support. I had a journaling website for about ten years. I closed it and started desert verde. In the journaling section of this blog, I am recreating the website. The FB page will be an extension of it with more quotes and exercises.

You can like one or both on the right side of the page. Please join me! Thanks!

Here’s a little nature to inspire you, the Rio Grande in October:

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Passive Solar – As Old as the Sun Itself

by nan on 2011/07/25 · 1 comment

There is nothing new about heating a living space with the sun. Ancient cliff dwellings in the American Southwest were dug into a south-facing cliff to capture the heat of the low, southern winter sun. At night, the rock walls radiated the stored heat to keep the occupants warm. Do you know how a sidewalk is hot in summer? That is the sun’s heat radiating to your feet. photo: NMSEA

In summer, the sun moves north and climbs high in the sky, almost directly overhead. By digging a home into the cliff wall, the native people created an overhang that kept out the high, mid-day summer sun.

I am sure civilizations older than this used the sun’s warmth to their advantage, too. My dogs lay in the sun on chilly days and move to the shade as they warm up. When they get chilled, they move back to the sunny spot. This is primal, innate behavior, which our oldest ancestors probably exhibited. photo: flickr PhillipC

Why haven’t we been using these principles of solar energy through the centuries? As energy prices remain unstable, solar is becoming more necessary and will need to become mainstream.

Fossil fuels are finite. They will not be available forever to heat and cool our homes. As they get depleted, prices will rise. We cannot grow more oil, natural gas and coal, but we can always capture sun, wind and water.
Fossil fuels also cause political struggle, greed and other negative energies. No one needs to die in the battle for fossil fuels when the sun, wind and water can supply our energy needs.

According to the EPA, buildings in the US account for:

• 39 percent of total energy use
• 12 percent of the total water consumption
• 68 percent of total electricity consumption
• 38 percent of the carbon dioxide emissions

It is clear that saving energy in your home will have a positive impact on the planet and your wallet. An energy-efficient home is a buffer against fuel price increases.

So… why not passive solar? When did our homes become fortresses against Mother Nature? Sure, we want protection from rain, wind, snow and critters, but from the element that warms and cools us? I don’t get it.

What are we afraid of?

Here are homeowners’ fears of passive solar heating:

> Their fabrics are going to fade.
> There will be too much glare.
> They’ll lose their privacy.
> The house will be cold.
> They have to keep the windows closed to keep the heat in, making the house stuffy.
> It’s expensive.

There are solutions to all of these:

1) The best thing to do is keep upholstered furniture out of the sun. There are fade-resistant fabrics, but the sun and the heat it produces are brutal on fabric no matter what you do.

2) Rotate upholstered furniture regularly to keep it from getting too much sun. I love rearranging furniture, but not everyone does, so this solution may not be for you.

3) Passive solar windows do not need to be across the entire length of the south wall. Depending on the size of the room and the wall, you can leave a generous space between windows. This creates shade in the home, a good place for upholstered furniture. This could also reduce glare.

4) Place light and open outdoor furniture where the sun comes in. The sun does not damage metal or wicker tables, chairs and etageres. Save your upholstered furniture for the north side.

5) Put no furniture on the south side, and let the sun drench a concrete floor that acts like the rocks in a cliff dwelling – thermal mass.

6) If you are worried about privacy, you can cover the windows with a film that blocks the view from outside, but is barely noticeable from inside.

7) A trombe wall will give you plenty of solar radiant heat without a window to the world. This is the best solution for privacy.

8) Window coverings and window films keep heat inside. Even if you don’t have passive solar, all your windows should be covered at night in winter and during the day in summer.

9) A heat recovery ventilator (HRV) efficiently exchanges stale indoor air with fresh outdoor air with no heat loss. I’ve been in homes and offices where an HRV was installed, and they never felt stuffy.

10) It’s not expensive to build a passive solar home or to retrofit an existing home. I have inexpensively put windows in sunny walls, which cut down on daytime heating. The money and fuel saved quickly offset the cost.

I think something solar should be written into building codes – a sunny window, a trombe wall or a sunny entry way/mud room. There is no excuse for not taking advantage of free, available sunshine, especially in sun-drenched places like the southwest desert, where I live.

Passive solar is an inexpensive way to save money and get a quick return. It’s a simple way to save natural resources, too. An added bonus is that there are no moving parts to break or maintain. Passive solar simply and quietly takes advantage of free, available sunshine.

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What Are Your Criteria for Building or Buying a Home?

by nan on 2011/07/11 · 2 comments

My friend, Drew, who has built a tiny house in North Carolina, posted a question on Facebook that generated a huge variety of ideas in the comments. The question was:

What are the TOP 5 things you think are important when considering the purchase or building of a home? For me it is overall cost (meaning final cost…after 30 years of mortgages), quality of materials, location, amount of windows for natural light, space for children.

This was my answer:

When I bought the house I’m in now, I was sold on two bathrooms, two covered porches, awesome views, close proximity to town, and incredible solar potential.

I’ve been thinking about this question ever since I wrote that. My response was based on my living situation almost 13 years ago when I bought this house. I was a brand new single mom with two young daughters, 4 and 8 years old.

> Two bathrooms were crucial as I envisioned my daughters as teenagers.
> Sitting outside to watch a New Mexico rain shower and lightning storm has been a big part of my life since I’ve been here (23 years).
> This house was as far from town as I was willing to live. The next village is seven miles beyond me, and that was a long haul for school, soccer and gymnastics.
> Most of the south side of the house was blank and screaming for windows!
> The views are endlessly changing and have a meditative quality.

Views from the porch – rainbow, sunrise and sunset

Empty Nester

My older daughter is gradually detaching herself from the home front, visiting less and less now that she has a full time job, is in nursing school, and is oh-so-grown-up at 21. The younger one will be a senior in high school this fall, then it’s off to college for her.

I have a 2000 square foot house, and I personally live in about 600 square feet of it. The rest won’t be necessary once I’m an empty nester.

So, ever since I answered Drew’s question with past information, I’ve been asking myself what I would want in a home once I am living by myself again.

A friend of mine owns a duplex. One side is 665 square feet with one bedroom, a full bath, a full kitchen and a living room. A storage area between the two units serves as a buffer for each. It also holds a washer and dryer, adding a little square footage, but not much.

This sweet place is built of super efficient pumice and has south windows for passive solar gain. There are rights to add another 400 square feet, but when I saw it, I knew it was enough room for me as it stood. I wanted to buy it once my kids grew up, but my friend turned it into a profitable vacation rental. Consequently, it has been my inspiration for downsizing for the last five years or so.

Empty Nester + 1

In the last few months, my situation has changed. A man I have known for 23 years and who I was deeply involved with 11 years ago is back in my life. We will probably join forces within the year.

My house seems like too much room for two people, but we both love solitude and alone time. This home grants that as well as office space for both of us.

Other benefits:

> There is enough room to grow food all year.
> The mortgage is cheap.
> Utilities average less than $100 a month.
> The views from the covered porch are incredible.
> It’s close to town.

So what happens to the 665 sq ft dream home? I can’t visualize us living in a space that small. I have mentally moved myself into it already, and I take up all the room! Where would I put Daniel?!

Option #2 – I could move out to his place, but it’s colder there than Taos, which is already too cold for me.
Option #3 – We could sell both properties and start over.

So much is still in the wind and will not be dealt with seriously until late fall, after farming season ends for him and school ends for me.

No matter what happens, my criteria for a home are:

> No wasted space
> Enough room for togetherness and private time
> Space to grow food
> Energy efficient
> Passive solar and solar hot water
> Views and a covered porch to enjoy them from

It sounds like I should stay put and do some gentle persuading………. And if that doesn’t work out, I’m still inspired by 665 square feet.

What stage of life are you in, and what are your criteria for buying or building a home?

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More on Solar Hot Water

by nan on 2011/05/06 · 2 comments

My friend, Eric Olriksen, a NABCEP certified solar thermal installer in Taos, New Mexico, has made this amazing video about how solar hot water is installed, how it works, and its applications. He has his own business now, Samson Energy LLC, but he installed my system when he worked for that company. Aside from being educational, this is inspiring, and I love the client comments at the end!

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My Solar Retrofit – An Energy Audit and a HERS Score

by nan on 2011/02/28 · 1 comment

(This is Part 7, the final installment of a series about the solar remodel I did on my house in 2007. Start here.)

The interior of the remodel was not complete, but the envelope was done enough to conduct an energy audit. I called my friend, Alva Morrison, who is a Certified Energy Rater. He’s been working in the state weatherization program for a long time and is very knowledgeable about energy conservation. Becoming an energy rater was a natural next step for him in his career.

We were going to conduct a blower door test. A huge fan was placed in the opening of an exterior door and sealed to be air tight. Then we sealed up the other exterior doors, closed all the windows and left all the interior doors open. We were going to need the air in the house to flow to the fan and outside in order to determine leaks.

Here are pictures of the fan from inside the kitchen and outside.

Alva measured the house to determine to volume of air it holds. He also asked me a lot of questions about my heating systems, insulation, building materials and the foundation. I also gathered up my utility bills so he could see my average annual energy use. All that data was input into the software on Alva’s laptop.

We put the laptop on a table by the door, and connected the fan to the laptop. You can see all the cords in the photo on the left. We turned on the fan, and it recorded the air flow through the house. At the same time, it analyzed the results based on the other information I had given him.

While it was running, we went around the house looking for air leaks. We were surprised to find them in some places and not in places where I expected them! The older windows had some spaces around them, and we caulked them. There was also a small space in the panel where I gain access to the attic space. We tightened that up, too, then rechecked the figures the software was spitting out. With just sealing up those areas, we had improved the house’s energy efficiency.

We were surprised at the analysis, recommendations and ROI, too. Alva included them in his report:

“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!”

Hopefully, I can get that work done this summer. It’s kind of back-breaking for me, but I have some energetic friends that could pull it off.

I had Alva calculate a HERS (Home Energy Rating System) score, because I wanted to be able to show others the entire process. Tangible results say so much more than academics.

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, analyze the results again, and give me new recommendations.

Many municipalities, including Taos, are beginning to require HERS scores and/or LEED certification on new construction. This is the only way were are going to get our building to be more efficient. I have found over they years that voluntary energy conservation doesn’t work. Mandates do.

I have now lived in the house for four winters since the remodel. My energy bills are very low. Here are some thoughts on energy:

> My gas bill for hot water, cooking and heating my daughter’s rooms rarely goes over $30, and in summer, it’s usually $18.

> Instead of burning 5-7 cords of wood, I burn about three. This is always hard to judge, because there’s usually wood leftover from the year before, and I burn a lot of scrap lumber and paper trash when it’s not very cold in spring and fall.

> I did not install solar PV, because my electric bill is about $25 a month. It would not be cost effective to install, since the payback would take so long. If I were gung ho about generating my own power and returning it to the grid, I would definitely have PV on my house. It would be a wonderful experiment!

> When I think of selling and moving closer to town for walkability and a smaller home, I figure my bills will be much more than they are here. Even though I have more space than I need, and I have to drive everywhere (I don’t drive to town every day, though), I am still using less energy than I would in a smaller home closer to conveniences. The gas bill in my hybrid car is certainly less than an increase in rent and utilities, so from a financial point of view, I am probably better off staying put until I sell and move away. There are always trade offs in the energy conservation game.

> I’ve cut my grocery bill by being able to grow food indoors year round. It doesn’t take much to do this. A few pots with greens and other cool weather vegetables offsets my food bill.

> Low-e windows and insulation work wonders to reduce energy consumption! I also bought a front-loading washing machine just before this remodel, and it measurably cut back on my hot water.

> Find a certified local Energy Rater through RESNET – Residential Services Energy Network.

Thanks for reading about my remodel! If you have any questions, please don’t hesitate to email me! nan at desertverde dot com.

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My Solar Retrofit – Solar Hot Water

by nan on 2011/02/22 · 3 comments

(This is Part 6 of a series about the solar remodel I did on my house in 2007. Start here.)

One thing I had wanted in a home for many years was solar hot water. I’ve had solar showers for camping (and power outage emergencies!), so I was aware of the power of the sun to heat water.

I understood how it worked, but I did a lot of research anyway. I found this at www.energysavers.gov:

Solar water heaters—also called solar domestic hot water systems—can be a cost-effective way to generate hot water for your home. They can be used in any climate, and the fuel they use—sunshine—is free.

Solar water heating systems include storage tanks and solar collectors. There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don’t.

Most solar water heaters require a well-insulated storage tank. Solar storage tanks have an additional outlet and inlet connected to and from the collector. In two-tank systems, the solar water heater preheats water before it enters the conventional water heater. In one-tank systems, the back-up heater is combined with the solar storage in one tank.

Two tank solar hot water system:

One tank solar hot water system:

My next step was to call installers for quotes. I first called (and ultimately hired) Valverde Energy. Larry Mapes, the owner, came out to the house, and we talked about my energy needs. My daughters were in high school and close to going to college. We decided to size the system for my future use living here alone. It could be added onto later when a family lived here again. The system would have been too large if I’d put in enough panels to cover laundry and hot shower needs for me and two teenage girls.

We installed a two-tank, active system, like the top image. The cost was about $7000. We crunched numbers and saw that it would pay for itself with energy savings in about six or seven years. I am halfway there! Actually, with tax credits, I’m probably even closer. I haven’t calculated that figure, but nevertheless, I love that the sun heats my water and that in a couple more years, my hot water will be free!

My solar panel being installed on the roof:

To make the most of solar hot water, it needs to be used in the middle of the day while the sun is doing its work. Later in the day, it is still effective, but not so much. I’ve already written about how to maximize your solar hot water.

My girls were home for two years before heading off to college and boarding school. Once I was home alone, my gas bill for hot water was about $15/month. I don’t make elaborate meals for myself, so that cost was mostly for hot water needs. When the girls are home on vacations, the gas bill does not go up much, since they sleep late and shower in the middle of the day or in the evening. I now have one living at home, and even with heating that room, my gas bill is not above $30. I credit this to the solar hot water AND a front loading washing machine.

Move on to Part 7, the final installment!

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My Solar Retrofit – Thermal Mass

by nan on 2011/02/14 · 2 comments

(This is Part 5 of a series about the solar remodel I did on my house in 2007. Start here.)

The way passive solar works is that the sun hits a mass, which absorbs the heat. As temperatures drop, the heat is radiated out from the mass. It’s a constant cycle of absorb and release based on the thermodynamic law that heat moves to where it is cooler. Again, I’ll bring up the hot summer sidewalk example. When it’s hot, it is absorbing the sun’s rays and heat. At night, it sends that heat out. This is why cities don’t cool off at night. Their concrete and asphalt are radiating daytime heat into the cool night air.

I have several sources of thermal mass in my greenhouse. An adobe wall was built along the north wall. The sun hits it, it absorbs the heat, then sends it out at night to heat the space.

This is the wall as the contractor was in the process of cleaning the mortar off of it:

This is my garden on January 1, being heated by the thermal mass:

This is a close-up of the tomato plants along the adobe wall on January 1:

The concrete wall of the planter bed also gets a lot of sun. I walk along the top of it to close the the curtains at night, and it is toasty! The soil in the bed and the concrete floor serve the same purpose. There are many areas where the sun comes in during the day, and each has the ability to absorb its heat.

The beauty of this radiant heat is that there are no cold spots in the room. It’s comfortable everywhere. It’s a very gentle heat.

Water is another excellent thermal collector. I’m sure you’ve seen pictures of solar greenhouses from the 70s where 55-gallon drums were painted black and filled with water as thermal mass. Sometimes you’d see the north wall of a greenhouse lined with 1-gallon jugs painted black. It’s all the same – mass to collect the sun’s energy to heat the space at night.

It’s great to have sunny windows to heat your home during the day, but they are even more effective when you can store the heat with some type of thermal mass for nighttime use.

Move on to Part 6!

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Green Home Recap 2.4.11

by nan on 2011/02/04 · 1 comment

As I sit here on Friday morning with no natural gas due to gas line disruptions in Texas, it’s a great time to reflect on green building. I’ve been wondering what I can do to make my house completely self-sufficient, short of turning it into an earthship. lol Thankfully, I heat the main part of the house with wood, and I have a solar greenhouse to help heat the bedrooms that have gas heaters in them. That works well when the sun is out. The weather forecast is for sun today, but then another round of snow and cold for five days. Maybe as this situation continues, I’ll get more creative in my problem-solving. In the meantime, here is some green building news I found over the past week.

> Blue Sky Homes to Build New Eco Home

> South Carolina church built with 2-ft. thick rammed earth walls

> Empire State Building Saving $4 Million with Windows Upgrade

> A Green Home Design by Anderson Anderson Architecture

> How to Maximize your Interior Views with Outdoor Landscaping

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