Cool Down with a Solar Attic Fan

solar_fan_roofOur prize for winning the 4th quarter of the Energy Showdown last year was a very cool solar attic fan.  It took us awhile to get around to installing it but we found plenty of motivation and dry weather in July.  I convinced my dad to come help, despite his preference to stay at ground level.  I took the fun job of cutting a hole in the roof (gotta love those sawzall projects) and then he helped me install the fan itself.

We were both a little surprised when the fan started spinning as he handed it up to me.  But it was sunny and the air temperature was above 80 and that’s all it takes for the fan to get to work.  The brand we got is called “the SunRise” from SRS (SunRise Solar, Inc) and it was made in Jordan, Indiana.  I’m happy to know we have some solar manufacturing in the state and so far I’m definitely impressed with the fan.

It’s a very simple one-piece unit that was pretty easy to install.  (For detailed instructions, check out this article from Home Power Magazine.)  My first step was to climb into the HOT attic and pick a location near the roofline and near the center of the attic.  I drilled a hole halfway between two rafters and left the drill bit in place. Then I climbed up on the roof, found my drill bit, stuck on the circular cardboard template that came with the fan, and used the sawzall to cut out a circular hole.  (I did nick the rafters on both sides but only a tiny bit.)

solar_fan_caulkAfter that, we pried the neighboring shingles loose so we could position the fan unit into place.  A few screws, a huge tube of caulk, and we were done!  We probably could have done the whole thing in under an hour but of course we had to take two trips to the hardware store – one for screws and a second one for a star-shaped drill bit that fit the star-shaped screws we had picked out.  Good times.

It’s hard to tell for sure how much of an impact the fan is having but it has definitely been running a lot.  The mechanics are pretty simple – there’s a photovoltaic panel attached to the motor but with a thermostat so that the fan will only run if the air temperature is above 80, which it has been for most of the last six weeks.  The goal is to pump hot air out of the attic, keeping it a little cooler and slowing down the amount of heat that seeps into our house.  I think it does reduce the burden on our air conditioner.  Yes, we have been running the air conditioner (set at a modest 81 or 82) although it’s mainly to keep the humidity down since we’re in Indiana swamp season (90% humidity nearly every day).  We also use fans, which make a huge difference.  Right now we only have a ceiling fan in the living room so we have a couple of box fans.  The trick is to minimize power use by only turning the fans on when you’re in that particular room since they don’t actually cool the air temperature; they just make you feel cooler by blowing away the layer of hot air around your body.  (Check out this post about staying cool from Mr. Electricity for a nice graphical explanation and some other non-AC cooling tips.)

Eventually we hope to add more ceiling fans but that will require an electrician.  For now, I’m planning to stick just with projects that involve cutting and gluing, which I think I mastered in kindergarten.

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Green as a National Park

Solar Panels in Denali Visitor CenterWill and I were lucky enough to travel to Alaska last month with his family and visit several amazing national parks.  Denali was probably the coolest (grizzly bears!  caribou!  huge mountains!) but I also was super impressed by the Kenai Fjords National Park with its coastal glaciers.  It’s pretty humbling being next to a giant river of ice and to watch an immense chunk break off with a loud “CRACK” and fall into the ocean.  Amazing.

While we loved the wildlife and the beautiful landscapes, we also enjoyed seeing all the ways the parks strive to be green, including quite a few renewable energy technologies.  It seemed like every building (even the outlying bathroom structures) had a solar panel on it.    Eielson Visitor Center, deep into the tundra of Denali National Park and with spectacular views of Mt McKinley, was the most impressive and is a LEED platinum building.  It’s essentially built into a hill with tundra plants growing on the roof to help it blend even further into the landscape.  One of their challenges (and motivations) is that there is no electric grid available 66 miles into the park.  So, the building uses several different energy sources (solar panels, hydroelectric generator in a nearby stream, and small propane generator) and was designed for maximal passive heating and lighting.  One advantage they have is that the center is only open for four summer months (June – September) because it is snowed in the rest of the year.

We happened to visit on the summer solstice, when the official sunrise was at 3:45 AM and official sunset was at 12:21 AM the next day (a 20 hour 36 minute day) but it never got truly dark –  just dusk-like.  You can generate a lot of electricity from solar panels on a sunny day in that part of the world!  However, they also have a lot of cloudy days so it has been an experiment to see how solar electricity and solar hot water work for the center.  I think it’s awesome that the parks are able to try out different technologies and do the best they can to have a minimal impact on some of the best natural landscapes in our country.

Electric Car for RangersIn Kenai Fjords, I snapped a quick picture of an electric car driven by the rangers.  I expect it makes a lot of sense for traveling between their two visitor centers that are about fifteen miles apart over flat paved roads (as opposed to driving through the backcountry).  We are still intrigued by the idea of getting an electric car for our household since so much of the driving we do is short distances on city streets with low speed limits.  However, it doesn’t look like it will bubble up to the top of the priority list anytime soon.  I guess we’ll let the parks work out all the kinks and then we’ll adopt the refined version.

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One Step Closer to Solar Electric Panels

Solar Pathfinder Reading of Our RoofThe good folks at SIREN gave a stirring presentation last month about how now is the time to switch to solar electricity.  Panel prices have fallen significantly due to the recession, electricity prices look poised to raise (at least here in Indiana where Duke Energy is spending several billion dollars to construct a coal gasification plant in Edwardsport and pass costs on to customers), and there’s a brisk market for renewable energy credits.  We had already caught the fever a bit and the talk just convinced us it was time to get an actual site assessment and cost estimate.

We’re working with Alex Jarvis of Solar Systems of Indiana, a quirky guy who knows a heck of a lot about solar.  He came out to discuss some different options and to do a site reading of a few potential spots using his handy dandy Solar Pathfinder.  It’s a very simple little device that maps shade to determine if a particular spot has a good solar window.  The image above is from the middle of our roof, which has a very good solar window of about 85% between the key sunshine hours of 9:00AM and 3:00PM – solar time.  (See rant on Daylight Savings Time below.)

pole-mounted-solarHe also measured a few other spots in our yard so we could think about doing a pole-mounted solar panel.  You could argue that the pole-mounted systems are a little on the ugly side but they are very practical in terms of maintenance – no climbing on the roof, no trying to patch the roof under the solar panels – and they are great for houses that have a shaded roof but sunny yard.  We are leaning in that direction simply because our roof is 20 years old and will need to be replaced well before the solar panels.  Alex actually has his panel (shown at right) configured so he can move it around during the day to maximize its exposure to direct sunlight and therefore maximize electrical generation.  He is the first to admit that is way too hardcore for most people but he is a tinkerer and enjoys fiddling.  Most people just retilt their panels twice a year at each solstice.  At the spring solstice, the panel is tilted closer to horizontal since the sun is higher in the sky during the summer.  At the fall solstice, the panel is tilted more vertical since the sun is low in the sky during the winter.

After that is the decision of what kind of solar panels and inverters to get, which I must confess is mostly Greek to me but Will is drooling a bit at the thought of enphase microinverters that broadcast all kinds of exciting data for him to analyze with a fine-toothed comb.  We’re looking at getting six modules that are each rated somewhere around 240 watts, giving us a system that is around 1.44 kilowatts.  Here in southern Indiana, we average about 4.7 hours of direct sunlight per day once you factor in cloudy days and the fact that our days are significantly longer in the summer but shorter in the winter.  In a perfect world, our solar panels would produce 6.8 kw-hr per day (1.44 kw x 4.7 hours) or 2,470 kw-hr per year.  However, there are some losses that we have to take into account with our lovely fudge factor friend, the derate factor.   The derate factor has several components:

  • Shade on our system.  Our solar window is about 85% open, 15% shade.
  • Losses from the inverter, connections, and wiring
  • Losses from dirty solar panels (we’re going to assume we can keep ours clean – with a hose if needed)
  • Losses from improper angling (again, we’re in good shape with a pole-mounted system that can be tilted at least twice a year)

In the end, we figure our derate factor is about 0.8 (meaning we lose about 20% of the ideal production level), which reduces our expected output to about 5.4 kw-hr per day or 1,970 kw-hr/year.  That should still just about cover our needs and in our area it’s not worth overproducing since the electric company will just keep rolling over our credits until we move.  If you’d like to try this game at home, check out the PV Watts calculator developed by the National Renewable Energy Lab.  Soon we should have some prices to go along with our power estimates but for now we’re excited about the possibilities and also trying to brainstorm how we might landscape our yard to make the solar panels blend in a bit.  Any and all suggestions are welcome!

Daylight Savings Time Rant:  Indiana only recently adopted Daylight Savings Time while staying in the Eastern Time Zone, and I am not a fan.  Today the sunrise was at 6:30AM and sunset at 9:15PM, which means our solar noon is really about 1:50PM and our key sunshine hours are 10:50 to 4:50.  It also means that the fireflies don’t come out until 10:00 and it’s awfully hard to schedule fireworks, bonfires, or drive-in movies that children (or I) can stay awake for.  I liked it better when we were in straight-up Eastern Standard Time and never had to worry about changing our clocks.

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Solar Furnace Verdict: We Like It A Lot But Our Savings Are Minimal Because We Live in the Cold

solar_furnace_2Winter has passed, giving us time to sit and review how our solar furnace worked.  It’s a bit tricky to evaluate exactly how effective it was since we made several other changes to the house last fall (sealing up gaps around windows, turning our thermostat down to 59) but we feel it made a huge difference.  Here are our thoughts and I’ll dig into the numbers down below.

The Good

  • Mmmmm, warm.  We enjoyed the sunny days when the solar furnace raised our indoor temperature to 72 while our gas furnace thermostat stayed set at 59.
  • Warm air did circulate fairly well through our house (although it did stay warmest in our living room, which is where Will has his home office and where the dog likes to spend her time).
  • The solar furnace reduced our output of carbon dioxide by 1,792 pounds between the electricity and natural gas conserved.
  • Since this was a demonstration project cost-shared by SIREN, it was a low-cost way for us to enjoy solar technology.

The Bad

  • Solar furnaces do absolutely nothing when it’s cloudy and can not fully replace a regular furnace.  (Having one made me much more conscious of when we have sunny days.)
  • Our dollar savings were pretty minimal, about $52 for the season.
  • Payback time would be 58 years (40 if you get the tax rebate) but “normal” people would see higher savings (see note below)

The Ugly

  • Someone who keeps their thermostat at 70 during the day would see much, much greater savings because they would be replacing a lot more gas/electric furnace time.
  • Someone who relies on electricity for heat would see much greater savings because it’s more expensive than a gas furnace (even counting both the gas and electricity needed to run a gas furnace).
  • Someone who lives in a place with more expensive electricity would also see higher dollar savings – our electricity is nominally 9.7 cents per kWhr, which is really about 12.5 cents with the fees added in.
  • It’s likely our solar furnace would be even more effective if we increased the thermal mass in our home to absorb that heat on sunny days and keep it longer into the night.  We could also use more insulation in our attic and crawlspace.
  • All these numbers should be taken with a grain of salt as we changed a lot of variables at once, which is a common challenge as people green their homes – who wants to make just one change and wait a whole year to document how effective it was?!

Now some numbers.  Last winter (November 2009-April 2010) we used about 352 CCF of natural gas (one CCF = 100 cubic feet of gas) while this past winter with the solar furnace (November 2010-April 2011) we used about 236 CCF.  That’s a reduction of about 33%.  Will took a look at the outdoor temperatures and overall they’re pretty comparable from winter to winter.

Part of the savings we saw is due to lowering the thermostat on our gas furnace.  We turned our thermostat down about six degrees during the day, from 65 to 59, and about 3 degrees at night, from 62 to 59.  Past studies have shown that homeowners reduce their energy usage about 1% for every 8-hour period per degree.  However, we’re guessing those studies were looking at people turning their thermostat down from 72 degrees and we’d expect energy savings to be smaller as you get lower.  (This is because it takes more energy to heat when there’s a larger differential between the outside air temperature and the inside air temperature.  Somewhere I saw a very pretty exponential curve showing this but I of course can’t find it right now.)

Let’s say down in our temperature range the savings is more like 0.6% for every 8-hour period per degree.  So during the day (roughly 16 hours) we would save 0.6% x 6 degrees x 2 time periods = 8%.  At night (roughly 8 hours) we would save 0.6% x 3 degrees x 1 time period = 2%.  That gives us 10% total.

We also caulked around all our windows and insulated our electrical outlets and attic doors.  Past studies say that can reduce energy usage 10-15% but our house really seemed pretty tight beforehand so let’s say it was just 8%.

The solar furnace is the rest, (so 33% – 10% – 8% =) 15% savings.  Not enormous but we enjoyed a much more comfortable home since the solar furnace would routinely heat our house up to 68 or 70 while we left our gas furnace thermostat at 59.  Dollarwise, our energy is cheap and therefore our savings were modest.  We pay about 55 cents per therm/CCF.  So our overall gas savings for the winter was a modest $64 ($0.55 x 116 CCF).  Out of that, only about $27 can be attributed to the solar furnace (45% of the total savings).

However, our gas furnace also uses quite a bit of electricity to run the fans.  Again, I had to back calculate to estimate how much since we can’t put a kilowatt on our furnace.  Our total electricity usage for the 2009-10 winter was  about 1943 kW-hrs over 6 months.  For the 2010-11 winter, it was 1,156.  That’s a difference of 787 kW-hrs but a big chunk of that can be attributed to our new refrigerator, which we found uses 1.9 kW-hrs less per day, or about 342 for the winter.  That leaves us with an overall reduction of 445 kW-hrs (a 22% savings over last year), which at 12.5 cents each would be a savings of $55.  Out of that, about $25 can be attributed to the solar furnace (about 45% of the savings) while the rest is due to the lower thermostat and weatherizing.

So our total solar furnace savings = $27 from gas + $25 from electricity = $52. That means our payback time on a $3,000 solar furnace system (installed price) would be about 58 years.  Not super.  However, there is a big tax rebate available that will refund 30% of the system cost, bringing the price down to $2,100 and the payback time to 40 years.  Still pretty slow but we are very sure the savings would be much better for someone who normally keeps their thermostat around 68 or 70.

In terms of carbon dioxide, we saved both on natural gas and electricity.  Natural gas generates about 12 pounds of CO2 per CCF of natural gas (according to the Carbon Fund).  So 116 CCF x 12 pounds = 1,392 pounds of carbon dioxide saved.  Electricity generated from coal generates about 2 pounds of CO2 per kW-hr (according to Kilowatt Coal).  So 200 fewer kW-hrs would mean 400 fewer pounds of carbon dioxide generated.  (As a side note, natural gas actually produces less carbon dioxide than coal if you convert everything to kW-hrs for a side-by-side comparison but in this case we’re sticking with CCF since that’s what appears on the gas bill.)

Total carbon dioxide savings?  1,792 pounds from the solar furnace, or about 9/10ths of a ton.  Whew!

So, our bottom line conclusions are:

  • Qualitatively, we really like our solar furnace.  It really cranks out the heat and we enjoy waiting to see when it will magically kick on and give us hot air from the sun.  On sunny days it will run from about 11:00 to 4:00 and can easily heat the house up 10+ degrees.  The fan isn’t too loud and with our open floor plan, the warm air circulates fairly well.  We have considered putting in a fan or two towards the far end of the house to improve circulation even more but have decided we like having our main living area be the warmest and our bedrooms be the coolest.   We would like to experiment with adding a little more thermal mass to the house (to soak up the heat and radiate it back into the house at night) and of course more insulation.
  • Quantitatively, we’re a little disappointed in the payback time but we think that’s mostly because of our radically low furnace thermostat setting.  The solar furnace performs the best during the spring and fall “edge” seasons when there tends to be more sun and a lower differential between indoor and outdoor temperatures.  If you’re determined to keep your indoor air temperature at 68 or 70, your furnace will run a lot during those periods and the solar furnace can make a huge offset.  However, we were often opening our windows during those periods to let the “warm” 60 degree air into our house.  And even during the coldest and darkest parts of winter, the gas furnace never really had to run very much to keep the house at 59 so there wasn’t a lot of usage to offset.

I’m going to try to get some data from two other friends who have solar furnaces who I believe keep their gas furnace thermostats at a higher setting, to see what they have observed.  I would also love to figure out how the solar furnace compares to installing insulation, in terms of return on investment.  What kind of savings would you see from $3,000 worth of insulation?  Maybe that will be our next experiment…

**UPDATE**  Our friend Woodie Bessler ran through some calculations to see how a $5,000 investment in a solar furnace from RREAL compares to buying $5,000 in photovoltaic panels at $5/watt and using them to run an electric heater.  His conclusion?  The solar furnace produces more heat in BTUs.  This made us feel good about our system.  However,

  1. The output is comparable if the cost of PV panels drops to about $3.85/watt.
  2. Excess electricity from the PV panels can be used to power other things, whereas excess heat from the solar furnace will do nothing (and may even be undesirable).
  3. An even better option may be to use PV panels to power a geothermal heat pump, which would produce three times the heat, meaning an equivalent amount of heat could be produced for about half the cost.

You can see a pdf of his calculations here.

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Insulate Yourself!

Since heating is usually a household’s largest expenditure of energy and the cost is low, insulating your house is one of the most cost-effective conservation techniques around. An even cheaper option is to insulate yourself, but how much good can that possibly do? We don’t often think about our clothing as insulation, but as long ago as 1946, scientists have examined the insulative value (similar to the R-value of house insulation) of clothes, which allows us to figure out what impact it would have.

These researchers created a scale that allows you to figure out your comfort level based on air temperature, activity level, and clothing. Their baseline, 1 ‘clo’, is the amount of clothing a normal person would need to wear to be comfortable sitting around at 70 degrees. 1 clo is the equivalent of wearing a business suit with normal underwear. To figure out the clo value of an outfit, you just add the clo values of each individual item.

Some common clo values are 0.1 for a short-sleeved T-shirt, 0.2-0.4 for a sweater, 0.25-0.35 clo for pants, and 0.22-0.77 clo for a long skirt.

For every 2 degrees Fahrenheit, you need 0.18 more clo to be comfortable (or you need to be more active). A pair of extremely insulating long underwear can be purchased for $25 and provide about 0.36 clo, which would allow you to drop your thermostat 4 degrees! Depending on where you are and what you’re heating with, that could save 15% on your heating bill.

I had a hard time believing those numbers, but I recently got a good pair of long underwear and they’ve made a huge difference in comfort.  That makes it pretty clear that insulating yourself can have a huge benefit, especially if you’re currently wearing just a T-shirt and slacks!

How can something as simple as long underwear be so efficient? Air is a good insulator, so keep still air near your body helps insulate you tremendously. Your body is already producing heat too, so all you have to do is trap it rather than using a lossy process like a heat exchange to produce heat. Best of all, you only have to hear the small area right around your body rather than a whole room or even a house.

Last year, my biggest problem was keeping my hands and feet warm. Since I primarily work from home, I had to have warm enough hands that I could type comfortably. Luckily, I’ve found that keeping the rest of your body warm keeps your hands warm too, even without gloves! When your head and torso are cold, your body adjusts by drawing heat away from your extremities. Warming your head and torso mean that your body leaves them alone and your hands and feet stay comfortable even when it’s well below 60F.

If you’d like to learn more about clos, I highly recommend the article in Low Tech Magazine that introduced me to the concept and the clo numbers I listed above (and more)!

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Clothing Swaps and Other Eco-Socializing Ideas

Seriously, this was STYLING in the 80's

I swear this was trendy in 1985

I’ve never been known for my stellar fashion sense (see photo, circa 1985) but my wardrobe has seemed particularly stagnant lately so I was excited when my friends Maggie and Siri invited me to the Second Annual Ladies Clothing Swap and Tea Party.  I don’t know how it compared to last year but this year’s event was AWESOME.  About thirty or so women showed up with bags of clothing that was quickly sorted by type – pants in one pile, dresses in another, t-shirts across the way…  The hostesses had made cute little handwritten signs for each pile and carefully propped up mirrors in strategic places around the room.

And then we all dove in.  Well, actually, it was one of those amazing instances of smooth flow without any direction or authority.  At any given time, there were some women trying on outfits while others gathered in the kitchen to drink tea and others found a cozy corner to sit and chat.  I had a wonderful time expanding my wardrobe but it was really the sense of connection with all these other women that made it an exceptional event.

I call it “eco-socializing” – an excuse to get together and strengthen the feeling of community while also achieving an ecological goal; in this case, efficiently recycling clothing by trading it with others.  Granted, a clothing swap may not be as obviously constructive as a barn raising or as altruistically beneficial as a volunteer river cleanup but I still think it’s an integral part of building a green society.  These are the kinds of events we need to be fostering in our towns and neighborhoods, along with canning parties, sewing circles, and leftover exchanges.  They don’t have to be about saving the planet; just about finding a way to spend some time with friends and neighbors while sharing resources in order to reduce waste and reinforcing shared beliefs about green living.

I suppose saving poor souls like myself from fashion tragedies is a worthy goal too.

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Nature Nerd Presents: Turkey Tracks

It’s spring in Indiana, which means the weather is playing nasty tricks on us.  Yesterday it was 70 degrees and sunny; today it was 30 degrees and snowing lightly.  That’s a bit dramatic even for us local yokels but a couple of false starts before spring truly sticks are pretty common.  I thought I’d take advantage of the cold weather to showcase some snowy footprints I spotted during a women’s retreat a few weeks ago staying in a little cabin in the woods.

My friend Lisa is actually a much better Nature Nerd than I am and was able to identify all the footprints we spotted while I focused on capturing them on film.  (Check out our flickr page for footprints from deer, raccoons, possums, and other critters.)   I was most excited by the turkey tracks because I think turkeys are super cool.  This is mostly from when I housesat for my boss out in the boonies one summer and got to see turkeys walking across a meadow at sunset, surrounded by fireflies.  They looked like little dinosaurs with only their reptilian heads sticking above the grass.

Wonder what turkeys eat in the winter?  Well, as we followed their tracks around camp we came across this pile of cracked acorns.  They look like a lot of work to me but I’m guessing turkey beaks are more efficient at these sorts of tasks than I am.  I believe turkeys also depend on different kinds of seeds in the winter, including corn or other grains from nearby farm fields.  They probably were quite happy at the camp where we stayed, which had a variety of habitat types including open meadows, wooded ravines, a lake, and nearby farm fields.  In the summer they add berries and insects to their diet.

We saw quite a few animal tracks in the snow, especially around the creek, but I figured we probably wouldn’t see any animals themselves as I am not a particularly lightfooted hiker.  We were also working hard not to slip on the icy trails and generally paying more attention to our conversation than any efforts to be sneaky.  However, an hour into our hike we came up a hill and suddenly spied a flock of turkeys running down the trail from us.  Sorta.  They were pretty far off.  Can you see them?

Here’s a cropped version of the photo where they’re a little easier to spot.  Lisa tried to get closer but they are surprisingly fast runners with their bobbing little heads.  They also seem undaunted by steep hills and underbrush that left me panting.  Guess I am not cut out to be a wild turkey!

Ah, well.  We weren’t really planning on a turkey dinner anyway so I’m just happy we caught a glimpse.  Maybe next year we’ll see that beaver…

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Solar Chargers

A Soleo solar charger left of a smaller and cheaper off-brandEven with our reduced electrical usage, installing enough solar panels to meet our average needs just isn’t cost-effective for us yet. Photovoltaic (PV) prices have dropped a lot in recent years so even though we can’t afford a big system, there are a couple of cheaper options for trying out solar energy on a small scale.

Before our first big train trip last year, I bought a small (and cheap!) solar charger for my cell phone. It’s about the size of a box of cards and has two suction cups so that it can be placed directly onto a window. Despite costing less than $30, the solar panel has a battery behind it so that you can charge the battery first and then hook up your phone later. That turns out to be a really good thing because it takes over a week to charge fully!

Something that I didn’t realize before getting this solar charger is that most solar panels require direct sunlight. When I put the charger on a south-facing window, it didn’t charge at all, despite getting indirect sunlight for most of the day. I had to place it on our east-facing window, where it got 1-2 hours of direct morning sunlight, for it to charge.

More recently, we won a much nicer (and more expensive–$90 or so) Soleo charger as part of the SIREN Energy Challenge. This solar charger has a built-in battery with three panels attached, each a bit larger than the first charger I got. When it’s open, the charger looks a bit like a tilted flower, with solar panels for petals (you put a pencil, included, through the center to keep it upright). The advantage of this charger is that you can rotate it so that it gets direct sunlight throughout the day. The drawback is that you do have to rotate it. This one only takes 2-3 sunny days to charge (or a little less than a week if you don’t rotate it) plus it has a larger battery (more capacity).

Both chargers have a bunch of adapters for changing a variety of cell phones. The Soleo also includes a USB adapter so that it can charge or run a USB-powered device. It can also be charged by USB if need be.

We have three different devices that we’ve tried with the charges: a normal cell phone, an iPhone, and an e-reader. Neither charger has a very accurate charge indicator, so it’s hard to know exactly how well they work, but the cheap charger would charge the cell phone fully and have some juice left over or charge the iPhone by half to three-quarters. It couldn’t charge the e-reader because it doesn’t have a USB adapter. The Soleo can charge the phone about five times from full or the iPhone once or twice. It can charge the e-reader about as well as it can charge the iPhone.

Are we saving any money? Not really. Cell phones, even power-hungry ones like the iPhone, and e-readers just don’t draw that much power. Over the course of a year, each phone probably uses less than a kWH each, so even if we charged all of them by solar, we’d be saving well less than a dollar a year. And, unfortunately, we can’t charge them by solar all of the time because they run out of power faster than the solar cells charge their batteries (especially during those cloudy winter days we’ve been having).

On the other hand, the chargers provide a lot of convenience under certain circumstances. On our latest trip, Maggie forgot her phone’s power cord but was able to charge it using the solar panel. I can also leave one of the solar chargers in my bag in case I need to use my phone more than normal. The cheaper one especially could be left in a car window to charge and you’d have it handy if you needed to quickly recharge a small electronic device.

The real issue is that most of the things we use draw a LOT of power compared to the amount of electricity a small solar panel can provide, even on a sunny day. If we were willing to keep our phones off more often or to use only small LEDs for lights, a small solar charger like these two would be enough to make a significant dent in our use. When compared to the amount of electricity a television or computer uses, the difference amounts to a rounding error.

I’d recommend getting a small solar panel to most people so that they can play with it, figure out the benefits and drawbacks of solar without a huge investment, and get a better sense of how much power a kilowatt-hour actually is!

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Bring on the Spring!

south side of houseI am so ready for spring.  I can’t stop garden planning and I’m ready to run out and start DOING things if only it would be warm & dry for two days in a row (don’t want to overly compact the soil).  I also need to spend a little time creating a [sigh] budget.  I wish I were either fabulously wealthy or super skilled at transforming society’s garbage into useful structures like trellises and fences and grape arbors and outdoor showers.  But as I am neither, I have to prioritize and I’m having trouble.

So right now I’m focusing on one of my ideas that doesn’t need to be implemented just yet: planting some vines to help shade our south-facing window.  It has been lovely to have this winter (although I might try to beef up our curtains next year with some thicker insulating fabric for night time protection) but in a couple of months we’ll shift gears to keeping heat OUT of our house and this year I’d like to do it with plants.  We already have some trumpet creeper vine that grows all over the front porch railing so I think with a few well-placed structures we can coax it into a window-shading growth pattern.  Hmmm, that sounds a bit like some sort of nasty disease but I mean my goal is to have the vines grow up and over the porch to keep out the sun but I also want to maintain a view from the window to the garden plus it would be nice to have sun on part of the porch for my solar cooker.

There’s also the design challenge that our porch already has a roof overhang that is relatively low (like the ceilings in our house, about 7.5 feet).  There isn’t a good place to hang brackets to suspend wires, as suggested in the Carbon-Free Home, and I’m afraid if I put any sort of pergola on the porch it would feel really low (especially if the plants sagged at all).

front_of_house_trellis_sketch_croppedSo here’s what I’ve come up with (as translated with my crude drawing skills).  On the left is a trellis that would run east-west, creating a truly shady spot in front of our front door.  On the right is a trellis that would run north-south (perpendicular to the house), nestled in the corner next to the stairs.  I would connect them with 4 or 5 wires running parallel to the roof overhang, where vines could grow and help shade out the noontime sun but leave the southeast corner of the porch uncovered so I could set up my solar cooker.

Next step: Life-size mockups with giant pieces of cardboard lurking in my garage and some leftover bits of kite string.  I think there’s a good chance this set up might be a little too low for comfort, although we might not know for sure until we grow some vines and see how dangly they are…  But you know we’re game for experiments!

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Energy Showdown finale

The 2010 Energy Showdown is now officially over and we kinda won! Okay, we didn’t win the grand prize, but we won the 3rd and 4th quarter prizes, saved about $300, and expect to save more in 2011. As a whole, participants reduced usage by over 11 megaWatt-hours (that’s over 11,000 kWh!). Since Indiana’s electricity is produced almost entirely by coal, that’s a reduction of 22,000 lbs of CO2!

At the SIREN meeting this week, some of the other families talked about their experience in the showdown. One thing that struck me was the diversity. The 1st quarter winners were a married couple who’ve been slowly improving their house over the past 5-6 years. The 2nd quarter (and eventual overall) winners were a family of four, who didn’t want to make any significant lifestyle changes. The 3rd and 4th quarter winners were us, who have pretty good habits, but were willing to try some pretty crazy stuff.

Despite our willingness to try things out, in the end, we didn’t have to do anything particularly difficult. Getting a new refrigerator was painless, as was caulking and sealing areas around the windows. Line drying was sometimes annoying, but wasn’t particularly bad. We’ve decided that 56 degrees is too cold, but we’ve discovered that we’re comfortable at 59.

I think that the biggest obstacle for most people to reduce their consumption isn’t the difficulty or discomfort, but the fact that usage is pretty much invisible. There are so many things that use electricity, and in such a hidden way, that it’s really difficult to know what your biggest energy hogs are. From the perspective of activities, it’s also difficult to know what things cost. How much electricity do you actually use to watch a movie? What if it’s streaming through a computer? How does that compare to playing video games? It’s hard to tell.

I think that if people had a sense of how much electricity (and money) they could actually save by changing their behavior, they’d do it. If my non-eco friends found out that it cost twice as much to watch a movie on TV as through their laptop, I think a lot of them would switch. I’ve talked about this some before, but I think it bears repeating. It doesn’t take crazy lifestyle changes or lots of money to make a significant dent (over 20%) in usage. You just have to spend the time to make the consequences of your activities more visible, at least to you. One way to start is to use a Kill-A-Watt to identify the appliances in your house that are the energy hogs (e.g. refrigerator, space heater) and look at the Energy Star ratings to know what benefits you might get from upgrading – as well as thinking about cutting usage entirely if you can (e.g. ditch that extra refrigerator in the garage).

It’s also extremely useful to track daily electrical usage overall to get a sense of your normal usage. This helps capture some of that hidden electrical usage – like water heaters, dryers, and furnaces that don’t plug into regular outlets – and also gives a baseline for comparing when you make changes. If you lower your thermostat from 59 to 56, how much energy do you save? We found it saved about 0.5 kWh/day and decided that wasn’t really worth it for the added discomfort. What if you line dry your clothes instead of using the dryer? We found it saved nearly 6 kWh/use and decided that was TOTALLY worth it (although we still sometimes use the dryer when it’s raining or freezing outside).

There are a lot of painless ways to reduce electrical usage but it can be hard to know where to start and which changes to embrace. With that in mind, Maggie and I are preparing to teach a class in energy conservation through People’s University (a city program where anyone can offer a class for their fellow citizens) and we’re also planning to publish an e-book for people who want to try it at home on their own. The class will meet two hours a week for four weeks and have homework assignments in between – like tracking daily electrical usage at the meter and measuring the most commonly used appliances with a Kill-A-Watt. Our biggest goal will be teaching people how to study their own electrical usage and figure out the best way to cut back, since it’s different for everyone. Sure, we can all do a better job turning off the lights when we leave the house and making sure our houses are well-insulated but there are a lot of other small changes to be made and we want to help people understand which will work best for them.

If the Energy Showdown participants in Bloomington were able to reduce energy usage by 11 megaWatt-hours in a year, just think of what it could look like if we all made an effort! And you don’t have to turn off your water heater or your air conditioning, we promise.

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