Are you interested in adding solar energy to your home? You can spend thousands of dollars on solar panels, thin film, inverters, batteries, water heaters, etc.

But solar doesn’t have to be expensive.

If you’re building a new home, or remodeling an existing one, you needn’t spend a great deal of extra money to take advantage of the power of the sun. Incorporating the principles of passive solar design will make your home easier to heat and cool, and keep you more in touch with the natural cycles of the day and year.

Passive solar heating is older than humanity. Just watch your dog or cat seek out the sunniest spot in the room – or a shady place under the fence when the day gets hot. He knows instinctively how to keep himself comfortable using the sun.

A passive solar home uses smart design rather than mechanics to stay warmer in the winter and cooler in the summer. If you’d like to incorporate passive solar into your home, keep in mind the five elements of passive solar design:

1. Orientation – In the Northern Hemisphere, the sun tracks from east to west across the southern part of the sky in the winter. Position the house so the longest side faces the sun to take full advantage of passive solar heat.

2. Windows – Large windows on the southern side of your home allow sunlight in to help warm the building. When you’re aiming for passive solar heat, keep north windows to a minimum. They don’t let in much direct sunlight anyway, and that way you’ll also be avoiding drafts from the coldest winds. In very hot climates you might want to keep sun-side windows small and open up the shady side to keep the building cooler. Many passive solar homes feature angled glass on the sunny side to capture a greater portion of the sun’s heat.

3. Shading – Even in cool climates you’ll have some hot days. And you’d be surprised how warm a passive solar living room can get on a bright sub-zero day. Window shades, curtains and awnings keep the sunlight from overheating your passive solar home on sunny days. With the sun higher in the sky in the summer, awnings and roof over-hangs alone can often effectively cut the solar heat in the summer.

4. Insulation – In passive solar design, you want to let the sun’s heat in through windows, and then keep it from escaping. It’s essential to have plenty of insulation wherever you don’t have windows – especially in the roof. It’s also a good idea to have insulated shades or curtains to help prevent heat loss at night.

5. Thermal mass – the biggest problem with passive solar heat is that you only get it when the sun is shining. It’s important to include heat-retaining material in your home’s passive solar design. Materials like stone or concrete soak up the heat when it’s plentiful and help keep the home from overheating when it’s warm. They also act as a heat “battery,” slowly releasing heat as the building cools. It’s especially good to locate these materials where the sun will hit them, like in the floor.

Cultures around the world have used passive solar design for thousands of years to keep their buildings warmer in winter and cooler in summer. You can, too! It’s a smart way to build energy-efficiency right into the structure of your home.

When most people think “solar,” they think in terms of solar power – electricity!  Solar electric systems, or photovoltaics (PV for short) allow you to power your home with the sun as fuel.

But if you’re shopping for your first solar system, it pays to do your homework.  PV isn’t the only type of solar energy out there – and it may not be the most sensible place to start.  If you are an average to heavy user of hot water – or would like to be – a solar thermal system may be your best bet.

Solar Water Heating

Solar thermal, or solar hot water, uses energy from the sun to heat your domestic hot water supply.  Put simply, it works like this:  an antifreeze solution flows through collectors mounted on your roof, the side of your house or on the ground.  The solution is pumped to a heat exchanger, where the heat is transferred to your domestic hot water supply.  The heated water is then kept in an insulated storage tank until you’re ready to use it.

Solar thermal can also be used for space heating purposes.

Solar Hot Water vs. Solar Electric: A Cost Comparison

The cost to put in a solar water heater is not much different than installing PV.  Solar thermal panels cost about the same as PV panels per unit, and the balance of the system plus labor is usually comparable in price.

The difference is in efficiency.  Thermal panels average about 40 sq. ft., vs. 15 for the PV collector.  That means you’ll get almost 2 ½ tomes the solar energy coming in.  Plus, the thermal panel converts over 50% of that energy into heat, while a good PV panel won’t get much more than 15%.

Add it all up and the solar water heater will give you about 10 times the energy output per dollar invested.

What’s Your Best Choice?

Is solar thermal always the best choice?  Not necessarily.  If you use very little hot water you may not be able to take full advantage of it – but most people benefit from putting in solar water heating first.  Fulfilling your domestic hot water needs with a properly sized system will give you a lot more bang for your buck.

Once you’ve done that, it makes sense to add solar electric.  The advantage of PV is that you can sell your excess solar power to the grid.  So once you’re set up with all the hot water you need, feel free to go PV!

The morning sunshine warmed the skins of the plump Greening apples I was peeling, releasing a sweet juicy odor that made my mouth water. Careful not to disturb the yellowjackets drawn to the scene by the promise of a fruity feast, I filled the black enamel pot with golden slices, sprinkled them with cinnamon and fitted on the lid. Then I rose from the picnic table and prepared to make applesauce.

I had no intention of going indoors – not on a day like this! Nor was I interested in overheating my home by firing up the wood stove, or in sweating over a steaming pot.

No, today I was going to pawn off the heavy work – on to the sun!

Introducing the Solar Oven

The solar oven is an exquisitely simple device that’s fun and easy to use. Basically it’s an insulated box, painted on the inside with heat-resistant black paint and covered at an angle with clear glass or acrylic. You can make your own or choose from several commercially available models.

Basically how it works is this: You put the food you want to cook inside a dark-colored pot or casserole with a lid; fasten the lid of the oven; and set it to face the sun. That’s it. Depending on your oven and the heat of the day, temperatures inside can reach up to 350° or even higher on a sunny day (although 250-325° is more typical.)

It’s a very relaxed way to cook. You don’t have to worry too much about burning your food because of the relatively low temperatures. On days you’re puttering around your homestead, a pause now and then to point your oven toward the sun provides a welcome break between chores, and really makes you feel in tune with the rhythm of the day. And on town days, you can simply set the oven due south and come back to an instant hot meal! (Although check the weather report first – it’s no fun to set out on a sunny morning and come back to find your dinner cold and half-done in the pouring rain.)

Getting the Most from Your Solar Oven

Here are a few hints that will help you master the basics of solar cooking.

• Make sure you have an accurate thermometer in the oven – and make sure it’s visible from the front when the lid is closed so you don’t lose valuable heat checking the temperature.
• If the day is partly cloudy or cold, keep an eye on the temperature. Much below 200° and your food won’t cook properly and may even begin to nurture dangerous bacteria. If in doubt, use a conventional stove that day.
• Many ovens come with attachable reflectors that funnel extra solar heat into the oven and extend its usefulness on cloudier days and into the spring and fall. They’re definitely worth it!
• Solar cooking is slow cooking. Solar ovens work best with sweet or starchy food, or with meats and stews. Delicate vegetables like green beans or broccoli tend to turn an unappetizing brown and are best prepared another way.
• You’ll almost always want to cook your food with a lid, even bread. Cookies are an exception. You can also “boil” eggs by placing them in oven next to your pot.
• You can even cook beans with the sun, but you’ll have much better luck by bringing them to a boil before placing the pot in the oven. Otherwise you may find it takes a day or two to cook a batch of beans!
• Let your oven do double duty. When you take out your meal, replace the pots with ones filled with water. If the sun’s shining hard, it will heat your dish water while you eat!

Cooking with the sun is a great way to save fuel and enjoy delicious food while living in harmony with the earth. If you don’t have one yet, be sure to put a solar oven on your homestead wish list!

Anne Michelsen is co-founder of Marathon Renewable Energy, Inc., specializing in solar hot water systems. You can read more of her work at YourGreenLifestyle.blogspot.com