Archive for July, 2010

Showering With the Sun

Maggie using the solar showerWill and I spent a pleasant hour in the hammock a few weeks ago talking about project ideas for the house.  He’s been especially focused on energy savings and was very excited about the idea of building a solar shower.  I have many fond memories of outdoor solar showers but the ones I have used in the past involve solar water panels, plumbing, welding, privacy screens, and several other features that would challenge my handywoman skills.  Ever practical, Will suggested that rather than plunging into a new construction project, we should pick up a simple camp shower and try it out so we could go ahead and turn off our hot water heater.

We picked up a solar shower kit at a local box store for $25 that consists of a curtain with a zipper, a solar water bag with a shower nozzle, and a support structure to hang it all from.  We hung the support structure and curtain from one of the big sugar maples in our backyard, filled up the water bag, and I took the first shower.  It was not a great experience.  The shower bag came with a long tube leading to a shower nozzle, which in theory gives you the flexibility to spray in many different directions.  In actuality, you have to keep the tube stretched out and sloping down to get decent water flow, which means crouching down and risking mooning the neighbors.  We had also neglected to stake down the curtain, so it was blowing around a bit and decreasing my feeling of privacy even further.

Solar Shower BagAfter that first shower, I cut the tube into a short piece so now I can stand under it comfortably (Will has to duck a little).  We put a piece of indoor/outdoor carpet under the shower so it doesn’t get too muddy.  It’s still a bit of a pain to fill, heat, and hang the bag but it’s doable.  Actually, the biggest challenge is keeping the water comfortable instead of scalding hot.  The solar shower heats up too well some days and we have to add cold water.

We’re going to try it out a little longer but I think it’s been successful enough that we will try building Solar Shower 2.0, perhaps using the directions from the Carbon-Free Home book.  They suggest building a platform of some sort and putting a small (10-gallon) black barrel up on it with a shower spigot sticking out.  Ideally, it should be designed so you can fill it from the ground using a garden hose (or rain barrel) so you don’t have to haul it up and down.  Sounds good to me!  Maybe we can build some actual walls around it too….

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The 3 kWh Challenge

After a poor April (with no year-over-year change in our electrical consumption), we got a new refrigerator and reevaluated our strategy. Reducing our furnace use helped a lot in the winter, but we barely used the A/C last year, so that wasn’t going to improve this year.

Thanks to the refrigerator, May was a good month. We were able to reduce our consumption by 50%! That brought our total usage for May to 121 kWh, which is a little over 4 kWh a day. Given that, I talked Maggie into trying to reduce our usage to less than 3 kWh a day in June. For comparison, leaving two incandescent bulbs on would use up the allotment for that day.

So June is over; how did we do? From June 1st to July 3rd, we used 79.9 kWh or a little under 2.5 kWh a day! Here’s how we did it.

No A/C – A/C isn’t as energy intensive as heating, at least in part because the temperature difference isn’t as high, but it still uses a lot of power. Running a typical central air system for half an hour can use over 1 kWh. Instead, we used blinds to reduce solar gain, opened windows when it was cool and closed them when it was hot, used the ceiling fan and window fans, and, on one particularly hot afternoon, took refuge in an air-conditioned movie theater.

No hot water – the majority of residential energy use is cooling and heating, including water heating. My best estimate is that our 40-gallon water heater uses 300 Wh (0.3 kWh) a day. We got a solar camp shower and we’ve also taken some cold showers. As a bonus, we cut our water use significantly since you don’t dawdle in a cold shower!

No clothes dryer – Our clothes dryer runs about 2 kWh per load! Now that it’s summer, we’ve avoided using it entirely and line dry everything. It takes more planning, especially since we had so many thunderstorms in June, but that’s quite the energy savings!

Reduced computer use – I have a small netbook that uses less than half of the electricity of my normal laptop. I was able to get even better numbers by using Windows’ power settings to dim the screen and slow the processor. I also made sure to take my charger with me when I worked outside the house. That doesn’t decrease my overall electrical use, but partly offsets the fact that I work from home.

Sharing space – In the evening, Maggie and I make sure we spend most of our time in the same room. That means we’re only running one fan and one set of lights. It’s not a big savings, but it’s also pretty easy to do.

We won’t be able to sustain it into the winter, and some of it is extreme enough that we might not be able to sustain it for more than a month or two. I think we’ll be able to keep it under 3 kWh for July and maybe August, but when it gets cold again, we’ll have to turn on the furnace. We also won’t be able to stop using the dryer entirely at that point. Still, for now, we’re feeling pretty good!

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Energy Star Appliances Rock!

our refrigeratorThis whole SIREN Energy Challenge has made us even more conscious of how much electricity we use and Will has become obsessed with switching off lights, unplugging appliances, and spending his free time trying to uncover the source of unaccounted energy use every month.  We thought we had made some major progress with our new water heater and our conservation efforts and were initially proud of our first quarter results – 11% less electrical use than last year.  Then we found out that the winning household cut their energy use by 35% for the quarter!

How did they do it?  They made a lot of little changes that we’ve also done like adding attic insulation, installing a programmable thermostat to lower their heat at night, caulking windows, and replacing light bulbs with CFLs.  However, they also made two big appliance changes.  First of all, they unplugged an underutilized chest freezer, determining that they didn’t need the space.  Secondly, they replaced their 1986 refrigerator with a new Energy Star model.

We don’t have a chest freezer but we immediately became suspicious of our refrigerator and got out the Kill-a-watt meter, which confirmed our fears.  The old fridge was using 2.6 kWhr/day, which was a big chunk of our daily usage.

Our “Carbon Free Home” book suggested insulating the fridge to try and increase its efficiency so we got some foam insulating board from the home improvement store and stuck it on with double-sided carpet tape.  (For those aesthetic types, they suggest building a wooden insulated box around the sides of the fridge and adding shag carpeting on the front for a little extra oomph.)  It seemed to help at first but then the electrical usage went back up, possibly because our house suddenly warmed up with the weather.  (We survived with the thermostat at 62 all winter long but in May 62 degrees started feeling really cold!)

I suggested that we look into getting a new fridge so Will started doing research and we figured an Energy Star fridge would be at least 50% more efficient, which seemed significant.  We shopped around a bit and although theoretically there are SUPER efficient fridges out there, we bought one that is simply VERY efficient from our local box star.

The results so far?  The new fridge uses less than 0.7 kWh/day, which is about one quarter of what the old fridge used.  Did you catch that?  It uses SEVENTY-FIVE PERCENT LESS ELECTRICITY!  We’re thrilled and feel like it was totally a good purchase, even though a payback time of 8 years still seems like a lot.

Of course, replacing the refrigerator was relatively painless (at least in terms of our day-to-day lifestyle).  We decided to push on into the lifestyle change category in the quest of fame, fortune, and fabulous eco-prizes.  Tune in next week as Will regales the world with tales of turning off our air conditioning, our water heater, and our clothes dryer in the quest of using less than 3 kWh/day….

Energy Tracking Note:

kWh/day = kilowatt-hour per day which is calculated by multiplying the wattage that a device uses by the number of hours it runs in a day and dividing by a thousand.  Here’s a link to a nice post about estimating appliance energy use provided by our federal government.  For real world testing, you can use a Kill-A-Watt device on anything that plugs into a normal outlet (so it doesn’t work for most clothes dryers and water heaters).

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