Green Energy & Great Homes SPECIAL COLLECTION
• Tiny Houses • 8 Easy Projects for Instant Energy Saving • Solar Heating Plan for Any Home
Cozy, Affordable and Inspiring
tiny homes
Start small, and you can enjoy mortgage-free living in a hand-built home. By Lloyd Kahn
I
n 1973, we published our first book, Shelter, an oversized offspring of The Whole Earth Catalog that featured 1,000 photos of buildings around the world. In those days, many people were looking for ways to escape the conventional suit/job, bank/mortgage or rent/landlord approach to housing. In Shelter, we encouraged people to use
their hands to build living space, to be creative, to scale back, to start small. Like a lot of other ideas from the ’60s, the concept of hand-built homes is popular once again. Tiny homes have been discovered not just by the public, but also by the media. The mortgage crisis has devastated housing in North America. Huge homes along with huge mortgages were, in the end, unsustainable. Millions of people have had the rug
pulled out from under them. Wages are down, jobs are scarce and rents are inching ever higher. We’ve gone through a long period of overconsumption, of people living beyond their means, of houses too big and incomes too small. As we witness the end of a pie-in-the-sky housing boom and enter into an era of increasing costs for that most basic of human needs — shelter — a grass-roots movement to scale things back is taking root.
lew lewandowski; right: shelter publications (3)
An Authentic Life, Doin’ What He Loves
Lloyd Kahn embodies the idea that we don’t quit playing because we get old, we get old because we stop playing. Here he is, skateboarding at 73.
Just a few years shy of his 80th birthday, Lloyd Kahn is among the most enthusiastic, dedicated, hardworking and athletic — yes, athletic — guys I know. If they were to put a photo next to the definition of “authentic” in the dictionary, it could be a picture of Lloyd. When Lloyd came back from his stint in the Air Force in the late ’60s, he went to work as an insurance broker. But what he really wanted to do was surf and build houses, and he seems to have quickly picked up the habit of doing what he really wanted to do. His first building project had a living roof. Then he built a home in Big Sur from railroad timbers and used lumber. He built geodesic domes for five years, before concluding that they don’t work well as homes. His present home in Bolinas, Calif., sits in the midst of a large vegetable garden, includes a striking 30-foot-tall hexagonal tower and is covered with hand-split cedar shakes. Today he is one of the world’s leading voices in creative, environmentally sensitive, human-centered building practices. His early books were about domes. Later his passion grew to encompass anything built with creativity and a conscience. A Lifetime Achievement Award. For more than 50 years, Lloyd has been sharing his passion about building with the world. His company, Shelter Publications, has published his series of unique books that have inspired thousands of us to build our own homes. In recognition of Lloyd’s exceptional contributions to wiser living, Mother Earth News presented him and his Shelter Publications team with a Lifetime Achievement Award (we’ve dubbed it the “Mommy”). — Bryan Welch, Mother Earth News Publisher and Editorial Director
Beach-combed whalebone rafters on a tiny house in British Columbia.
Off the grid, elegant, and on wheels.
Texas: Two lofts and a full kitchen and bath in 12-by-28 feet.
www.MotherEarthNews.com
41
Shelter ideas, 40 years later. Tiny Homes is our new survey of scaled-down housing circa 2012. Written mostly by the builders, it’s not consistent in anything other than the size of the buildings. The styles of writing are diverse, as are the photos. The little homes run from elegant to
shelter publications (5)
I started gathering material for a new book, Tiny Homes: Simple Shelter in 2009 and have been amazed at the activity in the small-house field. It’s a thrill to see such enthusiasm, variety and creativity in tiny buildings these days. Moreover, there’s a new audience: young people who are picking up on
Both photos: Basic construction of this Canadian cob house took three weeks.
42 Mother Earth News XXXX/XXXX XXXX
funky, from hand-built to bought, from super-cheap to surprisingly expensive, from thoughtfully designed to seat-of-the-pants, just-go-ahead-anddo-it dreaming. The maximum-size building here is 500 square feet — pretty small. But it’s an alternative if you’re young or single; if you’ve lost your job or your home; if you want to get out of rent or mortgage payments and cut back on stuff; or if, for any one of myriad reasons, you want to start over again in life. This alternative needn’t be permanent, but it may work for you right now. It needn’t be this small, but the ideas here are certainly antidotes to the overblown single-family houses of recent decades. It’s moving in the direction of small. You can hire a builder or buy a prefab kit, or, if you can find the time and can work with your hands, you can do the building yourself. This will save about 50 percent of your costs (labor and materials split about 50/50). Another economic fact: With a mortgage, over the years you pay back about
An owner-built, mortgagefree straw bale home on the Oregon coast.
A tiny Texas house nods to the Victorian era.
A traditional cottage designed by Tumbleweed Tiny House Company . www.MotherEarthNews.com
43
A Canadian float cabin with its floating garden.
shelter publications (3)
A Montana cabin designed to resemble a fire tower. 44 Mother Earth News XXXX/XXXX XXXX
A Special on Lloyd Kahn’s Books
Tiny Homes, Simple Shelter is the fifth in a series of books from Lloyd Kahn’s publishing house, Shelter Publications. Through September 2013, we are offering a 25 percent discount on his latest works, HomeWork: Handbuilt Shelter (2004) and Builders of the Pacific Coast (2008), as well as his newest book, showcased here, Tiny Homes (2012). To order, go to www.MotherEarthNews.com/Shopping and enter the promotion code MMEPAD43 on the bottom of your order review page, or call 1-800-234-3368 and give the promotion code to your customer service representative. (For an iBooksoptimized e-book version of Tiny Homes, go to www.SHLTR.net/th-ibooks.)
twice what you borrowed. Here we are in the midst of an electronic revolution, and you still need your hands to build a home. Your computer isn’t going to do it for you. It’s comforting that not all of the skills of the past have been superseded. If you embark on such an adventure, my advice now is the same as it was 40 years ago: Start small. Kitchen and bathroom back-to-back for efficient plumbing. Hot water from solar panels in summer; water-heater coil in the woodstove for winter. This is your core. You can live in it while you add on. In Shelter, we wrote that self-sufficiency was a direction, not an attainable
goal. The idea was to do as much for yourself as possible. Maybe not plowing fields with horses or making your own shoes, but doing something within the context of your life: remodeling a house, creating a studio, building a table or bed, or fitting in things such as a productive garden, chickens, homemade bread, or lettuce in pots on the windowsill. It’s a tightrope act, finding the right balance between work for others and work for yourself, between creating things with your own hands and buying things from others — just like finding the balance between sitting at a computer and physical activity. These are complex times. Do I live in a tiny home? Well, no. But
it started out tiny. When I began building, we slept in a bedroom that was barely big enough for the bed. We cooked on a Coleman camping stove in an outdoor kitchen (on a deck). Our home got bigger, but it started small.
Lloyd Kahn has been the godfather of hand-built shelter since 1970 and continues to lead the way. He lives with his wife, Lesley, on a half-acre homestead in northern California.
A covered deck provides additional living space in this Washington cabin.
www.MotherEarthNews.com
45
8
Easy Projects for Instant Energy Savings
With these inexpensive ideas you can reduce your carbon footprint and slash your energy bills. Spend $400 once to save $900 a year! by Gary Reysa
R
educing your home energy use is the best of winwin deals — not only does it reduce your carbon footprint, it also saves you big bucks on your energy bills. That’s especially exciting when you consider that many home energy improvements are fast, easy and inexpensive. Often, the savings from an individual project are small, but when you start putting them together they add up quickly. My family set a goal of cutting our total energy use, energy costs and greenhouse gas emissions in half, and we were able to meet that goal with the help of these simple home projects. We found these reductions in our energy use easy to accomplish without making any significant lifestyle changes. Here are the details: We cut our total energy use from 93,000 kilowatt hours (kWh) per year to 38,000 kWh per year. This is saving us $4,500 per year in energy costs, and has reduced our carbon dioxide (CO₂) emissions by 17 tons! Our rate of
return on the money we invested in this program is more than 50 percent — tax free. Altogether, we took on 22 different projects, including two solar heating efforts that have already appeared in Mother Earth News. You can find details about all the projects we’ve done at our home in Montana on my website, www. BuildItS olar.com. But those I’ll explain in the following pages are the fast, simple ones. These eight easy home improvement projects cost us about $400 and will save us at least $9,000 over the next 10 years!
Prioritizing the Projects
When you start looking at any group of energy saving projects, you’ll likely find a huge difference in the bang for the buck. In our case, it was the simple things — such as controlling the amount of power that our computers use or basic
Initial Cost
Savings per Year
Energy Reduction per Year
Personal Computer Power Management
$20
$178
1,780 kWh
3,560 lbs
Install Compact Fluorescent Light Bulbs
$50
$117
1,170 kWh
2,340 lbs
Seal and Insulate Heating Ducts
$20
$75
940 kWh
480 lbs
Reduce Infiltration Losses From House (Seal Leaks)
$50
$156
1,980 kWh
1,010 lbs
$5
$63
630 kWh
286 lbs
Insulate Windows With Bubble Wrap
$38
$75
960 kWh
490 lbs
Eliminate Phantom Electrical Loads
$70
$57
570 kWh
1,140 lbs
Use an Electric Mattress Pad
$125
$186
2,320 kWh
1,150 lbs
Totals
$378
$907
10,350 kWh
10,456 lbs
Vent Dryer to Inside During Winter
insulating projects — that had especially good paybacks. On the other end of the spectrum, the solar photovoltaic project we intend to do in the future will cost as much as all 22 of our other projects put together, yet will only account for 2.5 percent of the total energy reduction! Why was the total payback on our projects so good? The keys to our success were: • We did quite a bit of homework before we got started. We evaluated each project for what it would cost and what it would save, and threw out the ones that wouldn’t pay well. • Some projects cost almost nothing, but have big savings — you can see on the chart above that several paid for themselves many times over within the first year. These tend to bring up the average return of the overall effort. • We are do-it-yourselfers — this can make a huge difference in the costs involved in some projects. • Another bonus is that some of our energy improvements qualified for rebates or tax credits that further increased the money we saved.
Electricity and Greenhouse Gas
There’s another reason to do these projects. Cutting down on electricity use is very effective in reducing greenhouse gas emissions. Unfortunately, in the United States, most of our electricity comes from inefficient coal plants. Coal is a high carbon fuel, and compared to other energy sources, coal-fired plants produce a lot of carbon dioxide relative to the amount of energy they produce. If we’re concerned about climate change, we should be shutting down coal plants. Instead we are on course to build more of them — many more. To me, this argues for doing an especially aggressive job of trimming your electricity use. If you want to reduce your contribution to greenhouse gases, most people will be able to find many hundreds of kilowatt hours that can be saved easily and cheaply with minimal lifestyle change. We get our electricity from a coal-fired plant, so all the projects we did significantly reduced the amount of greenhouse gas we produce. Notice that the projects that save electricity reduce greenhouse gases by about 2 pounds of carbon dioxide per 1 kWh of energy saved. For example, putting our two home computers on a power diet saved nearly 1,800 kWh per year and 3,500 pounds of greenhouse gas!
istockphoto/mike clarke
The Top Eight Projects
CO² Reduction per Year
1
Personal Computer Power Management
Computers and all their related equipment, such as printers and wireless routers, consume a lot of power. Together, our two computers and related equipment used 270 watts whenever they were switched on, but we found there was an easy way to reduce this amount. We put all the computer junk on a power strip, so that at night we could turn off everything with one flip of the power strip switch. We also started using the energy saving settings on our computers. During the day, we have the computers set to hibernate if they are inactive for 15 minutes so that the computer stops consuming power. This saves a total of 1,780 kWh per year, 3,560 pounds of greenhouse gas, and $178 per year! Recently, we also started using a new gadget called the Mini Power Minder that automatically powers down all our peripherals when the computer goes into hibernate. At only $15, it’s a bargain.
Energy savings/year 1,779 kWh Initial cost $20 DIY labor 1 hour CO² reduction 3,557 pounds $s saved/year $178 Energy source Electricity 1st year return 890 percent 10 year savings $2,834
3
Seal and Insulate Heating Ducts
We sealed the exposed heating duct joints with duct mastic and insulated all the ducts that were not already insulated in the attic and the crawl space. That wasn’t many in my case, but it’s still worth doing. The cost for sealing ducts is minimal — a can of duct mastic costs about $5. The cost for insulating ducts is also low — about 25 cents per linear foot of typical ducting. I figured it cost about $20 total, because most of my ducts were already insulated. Unless you pay to have the ducts tested professionally before and after you insulate them, estimating the savings is a guess at best. Good sources say that duct losses are typically high — 15 percent to 30 percent on average of your heated air from the furnace is lost through cracks and openings at the duct joints. But in general, you can’t get at a lot of the ducting that runs through walls on an existing house. I focused my efforts on the ones I could get to in the attic, crawl space and basement. I estimated the fuel savings for my house at a conservative 3 percent. However, a man I know who has sealed many duct systems and then measured them says he can get measured leakages down to 5 percent. In other words, this project made
2
Install Compact Fluorescent Light Bulbs Throughout the House
gary reysa; power button: istockphoto/phil earley; cfl: istockphoto/eric delmar
We decided to replace all of our existing incandescent lights with compact fluorescent light bulbs (CFLs). There is a much larger variety of CFLs out there now than there were just a few years ago. You can find them for most situations, including for lights with dimmer switches and decorative bulbs. We spent about $50 on new light bulbs, after you factor in some rebates from our utility. Many utilities offer rebates on CFLs, so check to see whether yours does.
Energy savings/year 1,168 kWh Initial cost $50 DIY labor 2 hours CO² reduction 2,336 pounds $s saved/year $117 Energy source Electricity 1st year return 234 percent 10 year savings $1,861
(All calculations on 10-year savings are based on an estimated 10 percent increase per year in the cost of energy.)
It’s easy and inexpensive to add insulation around ductwork, and doing so could lead to big energy savings.
sense for my home, but it might save you much more than the figures listed below, depending on how well sealed your home already is. Just put it on your list of “must do” things. It may or may not bring you huge savings, but it’s easy and cheap to do.
Energy savings/year Initial cost DIY labor CO² reduction $s saved/year Energy source 1st year return 10 year savings
940 kWh $20 4 hours 479 pounds $75 Propane 375 percent $1,195
4
Most homes have many places where air leaks in and out, including around doors and windows, but especially around plumbing, wiring and light fixtures that penetrate into the attic or crawl space. We decided to caulk around all the windows, and seal wiring and plumbing penetrations from the living space to the attic. For this project, I bought a few tubes of caulking and some polyurethane foam in cans, which cost a total of about $50. You can find the obvious air leaks yourself because you’ll feel the drafts, but you might be surprised at some of the places your home is losing heat. The best way to find these spots is through a professional inspection, including a blower door test. If your utility offers this service, you should definitely take advantage of it. Then take every opportunity during the test to identify infiltration locations, so you can fix them later. Again, the savings for this project are hard to estimate unless you’re willing to pay for a professional test. I guessed that infiltration was cut down by 0.1 ACH (Air Change per Hour). This would amount to about 10 percent air leak reduction on a typical house having a 1.0 ACH, or 20 percent on a well built and tight new house. I estimate this reduction would be equal to 6,100,000 Btu/ year, which is equivalent to 73 gallons of propane burned in a 90 percent efficient furnace, or 1,980 kWh. Again, the cost is so low and the potential savings are so high that this project is a must-do.
Energy savings/year 1,980 kWh Initial cost $50 DIY labor 8 hours CO² reduction 1,009 pounds $s saved/year $156 Energy source Propane 1st year return 312 percent 10 year savings $2,485
gary reysa; caulk: istockphoto/carlin photo
Reduce Infiltration Losses (Seal Your Home’s Air Leaks)
If you have an electric (not gas) dryer, you can make this homemade filter using pantyhose. The filter allows you to vent the dryer indoors rather than outdoors, which takes advantage of the waste heat.
5
Vent Dryer Inside During Winter
We have started to route the clothes dryer heat vent to the inside of the house in the winter. We live in a very dry climate, so the added moisture is a benefit, not a problem. There are two major advantages of venting inside. First, you recover the heat that was added to dry the clothes (about 2.2 kWh per load). Second, you avoid bringing in cold outside air to make up for the air that the dryer is pushing outside. To vent to the inside, you need to have a dry climate, an electric (not gas) dryer, and a way to catch the lint in the dryer exit stream. The cost of this project was $20 for some tubing and a lint filter. Caution: Gas dryers should never be vented inside, because toxic combustion products are in the vented air. Electric dryers should only be vented inside if your climate is dry — be alert for any moisture problems.
Energy savings/year Initial cost DIY labor CO² reduction $s saved/year Energy source 1st year return 10 year savings
630 kWh $5 to $20 2 hours 286 pounds $63 Propane 315 percent $1,002
7 gary reysa (2); penny: istockphoto/skip odonnell
Eliminate Phantom Electrical Loads
New energy-efficient windows are an expensive investment, but there are simple fixes that will make your existing windows more efficient. One of the fastest and cheapest is to cover them with bubble wrap.
6
Insulate Windows With Bubble Wrap
This is a neat idea that comes from the greenhouse crowd. You can insulate windows using bubble wrap packing material by spraying a water mist on the window, and then applying bubble wrap. The bubble wrap will usually stay in place for the full season with one spray. The bubble wrap distorts the view, but does allow good daylight to come through. It’s a good option for windows that you don’t need a view out of. This is very cost effective — payback is usually less than one heating season. At the end of winter, you can just pull the bubble wrap off, roll it up and save it for next year. If you are going to use a lot of bubble wrap, it’s worth finding a dealer in packing materials to buy it from (or a greenhouse supply place). You can get bubble wrap from shipping companies such as UPS, but their prices are much higher. My cost was 27 cents per square foot for 141 square feet, for a total of $38. This is something you can do in a couple hours, and use until you decide on a longer term solution — if ever.
Energy savings/year 955 kWh Initial cost $38 DIY labor 1 hour CO² reduction 487 pounds $s Saved/year $75 Energy source Propane 1st year return 197 percent 10 year savings $1,195
I suggest we lobby our representatives in Congress to have all electrical devices labeled with the amount of power they use when they are switched “off.” These “phantom loads” are relatively small, but they add up to considerable wasted electricity. For now, the easiest way to find out how much power your appliances and gadgets consume even when they’re “off” is with an inexpensive meter, such as the Kill-A-Watt. You plug the Kill-AWatt into the wall, and then plug the device into the Kill-A-Watt. The meter measures power use and keeps totals for the time it’s plugged in. Other brands work similarly — WattsUp is another. In my home, all the phantom loads added up to a total of about 80 watts of power. That’s 700 kWh per year! With power strips, you can completely turn off everything plugged into them by turning off the power strip. I used power strips to eliminate 20 of the 80 watts, and that is what I show below. The remaining 60 watts is my fancy Dish HDTV receiver that always uses 60 watts. Turning it off has no effect on its power consumption whatsoever! The only cost of this project was a couple of power strips — about $20. I spent another $50 upgrading my satellite receiver. It still consumes power when it’s off, but only about 15 watts instead of 60.
Energy savings/year Initial cost DIY labor CO² reduction $s Saved/year Energy source 1st year return 10 year savings
569 kWh $70 4 hours 1,137 pounds $57 Electricity 81 percent $907
Most appliances use energy even when they are turned off. But by plugging multiple cords into power strips, you can turn them completely off with one flip of the power strip switch.
8
Use Electric Mattress Pads
Unlike electric blankets, the power consumption for mattress pad heaters is very low (about 0.15 kWh per night). By using these electric mattress pads to heat the bed, we’re able to keep the temperature of the rest of the house much lower and still be comfortable. We have two furnaces in the house, but since putting in the electric mattress pad heaters, we have been able to turn off the furnace that heats the bedrooms. The savings in propane is considerable, and the comfort is outstanding. Others have reported being able to do the same thing with good down comforters and the like, but we’ve tried that and it doesn’t work nearly as well for me. The mattress pad heaters vary in price, but ours was $125. The dollar savings were $186 per year.
Energy savings/year Initial cost DIY labor CO² reduction $s Saved/year Energy source 1st year return 10 year savings
2,320 kWh $125 0 hours 1,150 pounds $186 Propane 148 percent $2,963
gary reysa; money: istockphoto/skip odonnell
Gary Reysa is an accomplished do-it-yourselfer who has tackled dozens of home energy projects, large and small. This article is adapted from material on his website, www. BuildItSolar.com, where you can find many more projects.
If you keep your bed warm with an electric mattress pad, you can save energy by turning down the thermostat at night.
The Next Eight Home Energy Projects
Ready to tackle more home improvement projects? The eight projects featured in this article are those that yield big savings the fastest, but the eight projects listed below also yield large savings over time. Here are the costs and savings that Gary Reysa found when trying them in his home. You can read more about them on his website, www.BuildItSolar.com.
Initial Cost
Savings per Year
Energy Reduction per Year
Add More Attic Insulation
$256
$126
1,593 kWh
812 lbs
Add More Crawl Space Insulation
$210
$86
1,094 kWh
558 lbs
Buy a New, Efficient Clothes Washer
$400
$35
350 kWh
700 lbs
Buy a New, Efficient Refrigerator
$800
$72
720 kWh
1,440 lbs
Install Storm Windows
$450
$220
2,700 kWh
1,100 lbs
Install a Storm Door
$200
$17
216 kWh
100 lbs
$1,086
$258
3,159 kWh
1,525 lbs
$0
$44
438 kWh
876 lbs
$3,402
$858
10,270 kWh
7,111 lbs
Project
Install Thermal Shades Remember to Turn Off Everything! Totals
CO² Reduction per Year
Plan Your Own Projects When we started our series of energy improvement projects, our goal was to cut our power usage and greenhouse gas emissions in half. We’re amazed at how easy it was and how much money we saved. But houses and living situations differ, so if you’d like to tackle your own half plan, you may need to choose a different list of projects. Here are some tips for getting started.
a full list of projects to reduce your energy use. 1Make Build a big list of candidates to choose from. These are some helpful resources: EERE Consumer Tips: http://www1.eere.energy.gov/ consumer/tips/m/index.html Home Energy Saver: hes.lbl.gov Energy Star: www.EnergyStar.gov EEBA: http://eeba.org/ Rocky Mountain Institute: www.rmi.org
Don’t do projects that aren’t feasible for your residence or 2 situation.
Evaluate each project — estimate the cost, energy savings and greenhouse 3 gas reduction. For each project on your list, see if you can come up with at least a rough idea of what it would cost and what kind of energy savings it would achieve. In the project descriptions for everything we did, I’ve included how we estimated the cost, energy savings and greenhouse gas reduction.
ing penetrations from the living space into the attic if you have to wade through the 18 inches of loose-fill insulation that you just added. Also, your budget may require putting off some of the pricey projects until later, or you might just be more interested in some projects than others.
a master list of projects that you intend to do over time. 4Make Have fun and keep track of progress. Be proud of the results. 6Doyourthem! Using the results of your evaluations from Step 3, weed out the projects that don’t seem worth it. This should leave you with a good list of projects that make sense for your situation, economics and the planet.
the projects. Put them in the order you want to do them. 5Sequence
All things being equal, you might as well do the projects that save the most first. But there are other factors to consider, such as the fact that some projects may interfere with others if done too early. For example, it’s hard to seal up the electrical and plumb-
Keep your utility bills so you can see what progress you are making. The bills will also be helpful if you sell the house to show its improved energy efficiency. Here are a few other resources to keep in mind. If you are doing the insulating and weatherizing projects yourself, then Insulate and Weatherize by Bruce Harley is well worth the price. There are also some helpful how-to guides and plans mixed into these pages: www.BuildItSolar.com/Projects/Conservation/conservation.htm and www.BuildItsSlar.com/Projects/Projects.htm. — Gary Reysa
istockphoto/duncan walker
Some projects will be impossible for your home or situation — throw these out. You might want to put some projects that look like a big stretch on a separate list to be looked at later.
Solar
Heating Plan By Gary Reysa
for Any Home
Slash your home heating bills with this exciting solar project.
If you can build a deck, you can build this super system!
I
gary reysa
t’s time to take advantage of solar heat to reduce your dependence on fossil fuels and lower your heating bills. This simple, yet effective, system can be utilized in almost any home. Because the solar collectors and the heat storage tank for the system are built into a small new outbuilding, you don’t need to completely remodel your home to use solar heat. On sunny days (or even partly sunny days) the collectors add heat to the storage tank. When the house needs heat, hot water from the storage tank is transferred to the house via an underground pipe into a radiant floor heating system. The new building that houses our collectors is a storage shed, but yours could be a studio, playhouse or workshop.
Advantages of this approach
• The collectors are mounted at ground level, where they are easy to build and maintain. • The collectors can be oriented and tilted for maximum solar collection. • The collectors and the building can share a structure in such a way that the material costs and time to build are reduced for both the collectors and the shed. • The collectors look good integrated with the shed (see the shed at far right in the photo below). • You don’t have to find a space for a large thermal storage tank in the house. • The steeply tilted or vertical collectors located close to the ground benefit from light reflected off the ground, particularly when the ground is snow covered. And, vertical or near vertical collectors are less prone to overheating in the summer.
Considerations
There are many ways to build this system, but remember these design guidelines to ensure that your system works well: • The collectors should face within 30 degrees of true south and should not be shaded by trees or structures during the three hours before and after solar noon. Be sure to check carefully for any obstructions that would shade the collectors. • To minimize heat loss from the pipes that carry water to the house, the collectors should be as close to the house as possible. The pipes should be well insulated and the trench should be deep enough that the pipes are below the frost line for your area. • The thermal storage water tank must
be well insulated. This requires careful insulation and careful sealing of the tank lid. The system that distributes the heat within the house should be able to use water that is as low in temperature as possible. Lower temperature water for heating will allow the solar collectors to operate more efficiently and collect more heat. We added a radiant floor heating system to distribute the solar heat throughout our home. This radiant floor can make use of water as cool as 85 degrees to heat the floors. Our system is designed to be as simple as possible. It uses a design in which water drains back from the collectors into the storage tank for freeze protection. Because it uses plain water and the system is vented to the atmosphere, there is no need for expansion tanks, pressure relief valves, vacuum breakers, antifreeze or heat exchangers. The collector loop plumbing consists of a few feet of pipe and a circulation pump — that’s all. This simplicity reduces the cost and labor to put the system together, and the absence of heat exchangers increases efficiency. The total amount of work does add up, so be sure to allocate sufficient time — it’s not a one weekend project. But, it’s not rocket science. If you can build a deck,
you can build this system. Designing the System
The shed can be almost any design. We chose a modified gambrel roof to match the style of our existing garage and to provide a loft with good storage room. The only requirements are that the shed has a south wall or steep south roof extending to ground level and is large enough to provide the collector area that you want. To make it easier to integrate the collectors with the south wall of the shed, choose the south wall width, height and stud spacing to match the collectors. This may result in slightly unconventional dimensions. The best plan is to start from the size of the collector absorber plates and glazing panels, and work from there. We chose the collector bay frame width spacing of 481⁄4 inches so that standard 48-inch glazing panels could be mounted directly on the collector frames with no cutting. The quarter inch allows for glazing panel expansion. The absorber plates are the heart of the collector, and much of the collector’s performance depends on the absorber. The plates also are fairly difficult and time consuming to make because they consist of a series of copper tubing soldered to copper sheeting. The copper tubes are connected by mani-
folds. The absorber plates can be purchased with a selective finish that reduces heat loss, making them more efficient. We decided to buy pre-made StarFire collector absorber plates, then make the rest of the collector frame and covering from standard lumber and greenhouse supply parts. We used twin-wall polycarbonate glazing, which is slightly more efficient than single wall glazing and is easy to work with. In order for the collectors to drain back to the tank when the pump shuts off, the collectors must slope down toward the tank. This requires that the entire bank of collectors be sloped toward one end with a slope of at least one-eighth inch per foot. The plumbing also must be sloped, and no lines should be less than three-quarter inch diameter. We used 1-inch copper pipe. Build The Shed & Collector
The south wall of our shed is conventional 2-by-6 stud construction with halfinch plywood sheathing. There is no siding on the south side, and the sheathing also serves as the back wall of the collector. The collector framework is laid out right over the south wall sheathing. It is best to lay out the full collector frame on a flat surface so you can make sure everything fits and gang cut the notches in the frame for the absorber manifolds and the horizontal glaz-
Gary Reysa’s home in the foothills of southwest Montana. Heat collected in the shed (right) is transferred to the house (left) via underground water pipes. The collectors on the garage (middle) heat the garage with solar-heated air.
renewableenergy Solar Collectors
Radiant Flooring
Trench Water Line OUT Water Line IN
Water Tank
Install the glazing panels. We used 4-by-12-foot twin-wall polycarbonate glazing panels and secured them with 1-by-2-inch vertical strips screwed to the collector frame. These cap strips are ripped from composite deck boards, which are likely to last longer than ordinary wood strips. We used stainless steel screws to prevent rust stains. No caulk or glazing tape was used between the glazing panels and the collector frame — which has worked fine, with no leaks — and it makes removing glazing panels much easier. THE Storage Tank
The tank is large enough to hold about one sunny day’s worth of collected sun-
shine. On a sunny day, the tank can hold enough energy to heat the house through the night and part of the next day if it’s cloudy. A general rule of thumb is to have about 11⁄2 to 2 gallons of water storage per square foot of collector. The waterline of the tank must be several inches below the lower manifold of the collectors in order to allow the collectors to fully drain back into the tank. In our case, the 3-foot-high tank is sunk into the ground about 2 feet so the collectors could be mounted just over a foot above the bottom of the south wall. We chose to build a tank that uses plywood walls lined with an ethylene propylene diene monomer (EPDM) rubber membrane (pond liner). The tank bottom and walls are three-quarter-inch exterior plywood. The plywood is supported by a 2-by-4 frame around the base of the walls and a second 2-by-4 frame around the
Twin Wall Polycarbonate
Cap Strip
Absorber Plate Risers
2x4 Frame Stud
1” Polyisocyanurate Insulation
2x6 Shed Stud (24” O.C.)
1/2” Sheathing
Collector Cross-Section Top View
len churchill (2)
ing supports. When cutting the manifold support notches in the framework, be sure to allow for the fact that the absorber manifolds must slope and the lowest corner of the absorber panels must be several inches above the tank water level for drainage. Install the collector frame on the south wall sheathing. Use lag bolts with the heads in counter bores to make them flush with the front of the frame. Caulk all the outside edges to prevent air leaks. The front surface of the frame is the surface on which the glazing panels will be mounted, so make sure it’s smooth. Install polyisocyanurate insulation in each collector bay. Nail it to the sheathing with large head nails. Do not use polystyrene insulation inside the collector — it will melt. Drill a half-inch drain hole in the bottom board of each collector bay so that any water that might get in can escape. Trim the ends of the absorber manifold pipes so that they will fit together when installed in the frame, then place the absorber plates into the notches in the frame. We soldered the manifolds together using ordinary copper solder couplings. The supply line from the tank pump is hooked to the bottom manifold at the lower end. The return line is hooked to the top manifold at the higher end. The remaining open ends of each manifold are capped. Test the manifold for leaks. We included vents in each collector bay to reduce the likelihood of the collector overheating when no water is flowing through it. The vents consist of high and low openings in the back wall of each collector bay. Air from the shed enters the lower vent, flows through the collector and exits the upper vent. This flow of air provides cooling for the collector. The upper openings have doors to control airflow. Install the horizontal glazing supports in the previously cut notches. These are located just behind the glazing panels to support them and prevent them from buckling. We used electrical metallic tubing (EMT) conduit for the supports.
renewableenergy top of the walls. A single 2-by-4 vertical stiffener is used in the center of the long walls. A beveled vertical 2-by-3 is used in each corner of the tank to tie the end walls and side walls together. A metal tension tie extends across the top of the tank at the midpoint of the long walls and ties the top of the long walls together. This tension tie is necessary to keep the long walls of the tank from failing due to outward water pressure. The tank construction is important; it will be holding about 4,000 pounds of water! All joints should be carefully glued and screwed together. The tank must sit on a level and solid surface. We The water storage tank is built from plywood placed the tank on about 3 inches of and pond liner material. washed gravel, which had been leveled and tamped. When the tank plywood shell is com- caulk held in place with some staples and pleted, cut a piece of EPDM pond lining trim off the excess. material large enough to line the entire tank The tank lid is made from two layers with no seams. Lay the liner over the top of of 2-inch-thick rigid foam board glued to the tank and carefully work it down into a sheet of hard board. The bottom is covthe tank. After the liner touches the bottom ered with a layer of EPDM. The lid must of the tank, take off your shoes and work be firmly held to the tank to prevent water from inside the tank. Continue working vapor from escaping — we used lag screws. the liner into the tank until it is against the Be sure to mount the pump and conwalls. Work all the extra material in each troller where they are protected from low corner into a single, neat fold. Then secure temperatures. We did this by positioning the liner to the top frame with silicone both in a compartment close to the stor-
age tank, with most of the insulation detouring around the outside of it so the compartment is kept warm by heat from the tank. Most of the pipes coming into the tank go over the top edge then down into the tank. This eliminates penetrating the EPDM liner and reduces the potential for leaks. The exception to this is the pump inlet connection, which does penetrate the tank wall. This is necessary because the pump must be mounted below the tank waterline to retain its prime. Use a high-quality bulkhead fitting for the connection through the tank lining. Heat Transfer Trench
The trench for the transfer pipes should extend below the frost line, and insulation of the pipe is very important. For our 120 feet of pipe, about 3 percent of the heat energy in the water is lost on the round trip. We used three-quarter-inch Chlorinated Polyvinyl Chloride (CPVC) pipe for the supply and return lines. PEX pipe would probably also work well. We made the insulation for the pipes by cutting 8-inch-wide strips of 2-inch-thick extruded polystyrene (pink) insulation board. Two three-quarter-inch grooves are
gary reysa (2)
Light reflected up off snow will increase the effectiveness of the collectors. To avoid snow accumulation on the collectors, make them vertical (instead of tilted) and add an overhang to the shed.
renewableenergy
Heat Distribution
We decided to remodel our floors to include hydronic radiant heat. The solar heating and radiant floors make an efficient combination, plus we didn’t like our old floors. We did this by removing the existing finish floor and installing three-quarterinch plywood spacers with slots between the spacers for PEX tubing. Aluminum heat spreader plates were used to improve the efficiency and eliminate hot spots directly over the PEX-Aluminum-PEX. This is a type of PEX tubing that has a layer of aluminum sandwiched between two layers of PEX. The advantage is it expands much
less than standard PEX when heated, so floor noises are less likely. It is also easier to install, because it retains its shape when bent. After the PEX was installed, we covered the floors with laminate flooring. As a rough guide, three loops of about 250 feet each (a total of 750 feet) were enough to distribute the heat from the 240square-feet of solar collectors. All of the floor heating loops start and end at a common point. One end of each loop is connected to the supply manifold; the other end, to the return manifold. Water from the storage tank is pumped into the supply manifold, then out through the floor loops and back to the return manifold where a pipe takes it back to the storage tank. If water from the storage tank is too hot to go directly to the floor, a mixing valve installed in the supply line mixes water returning from the floor loops with the supply water to bring the temperature down to a level that is safe for the floor. We
used a commercial set of supply and return manifolds that included all the fittings, air vents, valves and temperature gauges. Automatic Controls
The controls for the system are simple and operate the system efficiently. A standard Goldline differential controller is used to control the pump that circulates water to the collectors. It senses when the collector is hotter than the tank water and turns on the pump. For the first month, we just noted when the tank temperature was above 90 degrees and manually plugged in the pump to circulate hot water through the floors. When the tank went below 90 degrees we unplugged the pump. This is surprisingly effective, and it gives you a good feel for how the system is operating. I have since installed two electronic thermostats. The first turns on when the tank temperature is above 90 degrees, and the second turns on when the room temperature goes below 70 degrees. These two
Heat from the solar collectors is distributed through a radiant floor heating system using PEX tubing running through aluminum heat spreader plates. A hot water baseboard heating system is another option.
Resources Gary Reysa’s Website www.BuildItSolar.com Solar Site Survey (to check for shading) www.BuildItSolar.com/SiteSurvey/ site_survey.htm Collector Absorber Plates www.SolarEnergy.com Differential Controller Goldline GL30 (available from multiple sources) Electronic Thermostats Johnson Controls A419 (available from multiple sources) Twin-wall Polycarbonate Glazing www.Greenhouses-etc.net/glazing/ twinwall.htm (also available from other greenhouse supply outlets) gary reysa
cut down the length of each strip for the pipes to sit in. One 8-inch strip goes under the pipes. Another strip fits on top of the pipes. The strips are glued together with polyurethane foam insulation from a spray can. The strips can be weighted or tied together until the foam cures.
Collector Pump and Circulation Pump www.IAQSource.com/ (search for “taco”); www. us.grundfos.com/
renewableenergy thermostats are wired in a series, such that the pump is only turned on when the tank is hot and the house is cold. And, because the thermostats both run on 120 volt AC, there is no need for low voltage control wiring or relays. The control system is set up to use heat as soon as the storage tank is hot enough to supply useful heat. Using the heat as soon as the tank reaches 90 degrees rather than waiting for the tank to get hotter increases the efficiency of the collectors and also reduces losses throughout the system. For example, on a 35-degree day with full sun, the collectors will operate at about 59 percent efficiency if the tank water is at 90 degrees, versus 42 percent efficiency if the tank is at 150 degrees. Performance Data
Here is performance data for two sample days from a recent January. Jan. 12, 2007: A very cold sunny day. At 10 a.m. when the collector started gathering heat, the outside temperature was 20 below zero! The collector warmed the storage tank water from a morning low temperature of 85 degrees to 125 degrees in the afternoon. This heat energy stored in
the water is the equivalent of 2 gallons of propane burned in a furnace of typical (85 percent) efficiency. Jan. 27, 2007: A typical sunny winter day with a high of 30 degrees. The tank warmed from a morning low of 85 degrees to an afternoon high of 132 degrees. This is the energy equivalent of 21⁄2 gallons of propane burned in a typical furnace. Cost and Return
The cost of the solar system components was about $4,200 total. This includes Montana tax credits and an allowance for siding that would have been needed for the shed if the collectors hadn’t covered the south wall. I estimate that the system will reduce our propane use by about 340 gallons per year, now worth about $740 in our area. The simple payback period is about 51⁄2 years (at the 2007 price for propane). Other Opportunities
Solar heating of water for domestic use could be included in the design. By preheating water when the full output of the collector is not needed for space heating, the system would earn a greater return. You may want to use some of the col-
Show off Your Solar We’re always looking for photos of attractive solar homes to possibly profile or feature on the cover of Mother Earth News. If you have photos you’d like to share with us, post them online at Flickr.com/Photos/MotherEarthNews
lector heat to warm your new collector building. You could use the venting scheme described above to provide heating. By using some of the collector output for heating the new building, somewhat less heat is collected for the house. But, the collector will operate more efficiently with air flowing through the vent system. If you choose to do this, be sure to insulate and seal the new building well. Gary Reysa is passionate about solar heating. He’s been fighting Old Man Winter with solar heat since moving to Montana. If you have comments or questions about this project, post them to this article online at www.MotherEarthNews.com, or e-mail the author at gary@builditsolar.com.
Lessons Learned: You Can Build Your Solar System Even Better!
While the project has been a success, and we are quite satisfied with how it works, there is always room for improvement. Here are some things we would do differently: 1. Use vertical collector panels (rather than tilted at 70 degrees). This would: • collect nearly the same amount of energy • be less likely to overheat in the summer • collect much less snow during snowstorms • be easier to build and easier to fully integrate the collector into the wall 2. Include a small overhang with a gutter above the collectors. This would shade the top of the collectors in the summer, and the gutter would prevent snow melt from dripping on the collector glazing. 3. Make the collector frames from 2-by-6s instead of 2-by-4s, which would allow room for more insulation behind the absorber plates and a little more space between the glazing and the absorber plates. 4. Fully integrate the collector into the shed wall, so that the collector framing is the same as the wall framing. This could be done with 2-by-6 studs at 4-foot spacing — perhaps with a heavier top and bottom sill — depending on the size of the shed. The combined sheathing and collector back could be applied to the inside surface of the studs. This would save some additional money, material and labor. 5. Include a layer of the polyisocyanurate insulation inside the storage tank plywood walls. This is the best place to put insulation, because there is no tank framing to fit the insulation around, and no thermal bridging. The tank could be made a bit taller to make up for the lost volume. 6. Reduce losses in transferring heat to the house by building the solar shed closer to the house and/or insulating the underground pipes even better. 7. Connect the collector manifolds together using either unions or high temperature silicone hose instead of the soldered couplings.