How to Run Your House Solely on Solar Power

By: Cherise Threewitt  | 

Are you ready to go off the grid? Want to learn more? Check out these solar power pictureshome construction pictures!
Kerstin Klaassen/Photographer's Choice/Getty Images

The real question might be, why wouldn't anyone want to convert the family homestead to function off the sun's rays? Sounds like quite the formula for happiness, right?

The truth is, deciding to go solar has some pretty big benefits -- but they're somewhat offset by potential drawbacks.


Solar power is free, after the initial investment of setting up the system. Solar power is also efficient (although its actual level of efficiency is debated by some experts) and free of pollution. But once you decide to go fully solar -- off the grid -- you've got to cope with foul weather that might put a damper on your plans.

If you stay on the grid (the traditional electric system), you can still use traditional utility-provided power in situations where you can't make enough power or don't have any power stored. The goal is often to eliminate the need for fossil fuels entirely, but this option might be enough to convert some skeptics who are hesitant to make the leap. The terminology might also be off-putting, since "going off the grid" is sometimes associated with tax dodgers and serial killers. Rest assured, a wholehearted solar home is entirely wholesome.

Planning to run your house completely on solar power requires considerable financial, mental and emotional investments. The infrastructure is a little more complicated, the calculations must be more precise, and a mistake can leave you without enough juice to get by. At least there's already a light to guide you along the way.


Concentrating the Rays

The first practical instance of controlling the sun's energy might have been when someone noticed that a magnifying glass, held at the right angle, could set fires and burn ants. And from there, it was practically eons before humans discovered a way to use the sun's rays truly constructively.

The first silicon photovoltaic cell (what we know of as "solar panels") was produced in the United States in 1954. Our current solar panels are a direct descendant of this technology -- they've just been made more efficient over the years.


Over the years, from the 1950s through now, various residential and commercial buildings were developed with different solar priorities. One office building gained recognition for solar water heating. Residential milestones went from sunrooms to hybrid solar/grid systems to standalone fully solar homes (one of the first of which was completed in 1983). In 2000, a Colorado family completed a solar installation that nearly completely powered their home for their eight-member family.

There are other useful innovations besides roof-mounted solar panels, such as a modified version of a radiant heating system. By carefully routing the home's plumbing, water can be heated by the sun and, as it's pumped through the house, that heat can be dissipated to help control the house's temperature. This type of heat won't add to the home's electric consumption. In a nationwide solar home design competition in 2007, a group of students from Santa Clara University in California even figured out how to use a solar radiant heat system to help cool the house, as well as heat it. As appealing as this idea is, it may be particularly difficult to execute; a Tennessee couple who designed a home with a similar system had trouble finding a contractor up to the challenge [source: Lewis]. The Tennessee house, though not part of a competition, evokes the same sense of spirit. It's notable for its use of SketchUp, an architecture and design program from Google. The home's other features include energy-efficient LED lighting and insulation derived from corn.

Some designs give more responsibility and flexibility to the home's occupants. In the 2007 competition, a team from Virginia Tech added weather monitors to the house, which, among other features, would help the residents decide when to open and close insulated window shutters to maintain the desired interior temperatures as efficiently as possible. In 2010, there was a similar competition in Europe. A group of students in England focused on designing a prefabricated house that could be ordered and assembled anywhere -- and they made sure it complied with the country's most restrictive building codes. They hoped to demonstrate that prefab solar houses were an approachable and desirable alternative to custom construction or an inefficient conversion of an existing home. As a bonus, the assembly-line simplicity of prefabrication might negate concerns about wasting energy with new custom construction projects.

Cost, of course, can make or break any initiative. The price of solar technology has held fairly steady from decade to decade, but there were a few notable improvements. Solar cell prices were reduced by about 80 percent in the 1970s, which drastically improved their potential. And in February of 2009, First Solar, a manufacturer of solar panels, announced that the cost to make its wares had dropped to a dollar per watt -- an eagerly-anticipated milestone. Experts say that "grid parity" is the necessary milestone to making solar power really work. Grid parity is achieved when solar power costs the same as conventional power -- without the help of the grants, subsidies and rebates that make it possible for many customers. At that point, the supply probably won't be able to keep up with demand, since some of the solar panels' raw materials are hard to obtain in large quantities [source: Hutchinson].


Like Vitamin D for Your House

Solar panels attached to roof shingles create energy while being tested at the National Renewable Energy Laboratory (NREL) in Golden, Colo.
Solar panels attached to roof shingles create energy while being tested at the National Renewable Energy Laboratory (NREL) in Golden, Colo.
John Moore/Getty Images

To envision how solar power can provide enough juice for a whole house, it's necessary to cover a bit of the basics. We've probably all seen traditional solar panels by now -- flat, glare-inducing, unwieldy-looking things that jut from rooftops. They certainly aren't streamlined in any way, which makes them seem cumbersome. As we discussed, their ongoing refinement has gained some critical respect in the industry, but they still work about the same way.

As solar panels protrude from the precipice at various angles, they capture whatever sunlight is available, and convert it to DC power. An inverter converts the DC power to AC power (which is what we use to power electronic devices). And for people who want to completely power an entire home with the sun's rays, there are systems available to convert and store extra power in the form of battery energy. This way, the house still can have a source of power at night or in poor weather (but -- and this will be important later -- it can't cover the shortfall of a poorly-designed or inadequate system).


Solar shingles are a recently available option, a subtle, streamlined alternative to those telltale glaring flaps. They are solar panels, made from the same materials as traditional solar panels, that also happen to be shingles, and they look pretty much like a regular roof...perhaps just a bit shinier. Solar shingles, contrary to popular belief, can work even in weak or scattered sunshine conditions (which implies, but doesn't confirm, that shingles outperform panels in such circumstances). 

So, why does converting to solar take a bit of persuasion? Generally, houses in the United States can get heat either from gas or from electricity. For the sake of argument and purposes of this article, let's assume that someone gung-ho ongoing solar wants off the grid entirely -- and that means no gas or electricity. So, solar power needs to accommodate for heating, air conditioning (which, by far, is one of the biggest drains of power in a house), other parts of the house's infrastructure like lighting and vent fans, all major appliances (refrigerator, stove, washer and dryer), and other electronics like the microwave, stereo, television and computer. This list, of course, is by no means comprehensive (how many members of your family need to constantly charge their smartphones or tablets?), and there are a lot of variables. If your house is huge or you're a power hog who leaves the electronics on all day, you'll need a more intense solar setup. It would be nice to assume that anyone serious about performing this conversion is already pretty conscious of consumption and makes an effort to reduce power usage, like using insulated window shades instead of cranking the a/c, or foregoing a dishwasher that heats up and churns for hours. Right now, that's probably a fair generalization, but as solar goes more mainstream, the eco-conscious early adopters might not be the majority. The point is, you have to calculate all the electricity your house uses, and for the amount of time per day, and assemble a solar panel setup that can meet that demand. If it seems like too much, try cutting back on your consumption for a while and see if the numbers become more realistic.

Though it's certainly complicated and definitely not cheap, people with the resources to design and build a solar-power home from scratch have some advantages when it comes to flexibility. A lot of subtleties come into play when planning a residential solar system for a specific existing house. The actual design of the house is one such factor. How big is the roof's surface (which affects its potential solar surface area)? What direction does the roof face, and what's the degree of its pitch? Are there obstructions that cause partial shade? You can see most of these obstacles are impossible to change, but you might still be able to work with them. Location is also a factor. A house in Scandinavia, with its notoriously short days, won't fare as well as a house near the equator. The average number of sunny days matters too; if it's raining until nightfall, it doesn't particularly matter if nightfall comes late.

When you're trying to figure out how much power you can produce and how much you'll need, it's helpful to look at meteorological data for your area. It'll show you how much sunlight you can expect in any given month, based on past averages. You should have copies of your utility bills nearby, which will let you know how much power you use, and you can use this information to figure out if the system you want will make enough electricity. General guidelines recommend a setup that generates 1 kilowatt per 1,000 square feet of house. Don't let your optimism take over -- you need to ensure you can produce enough power to get you through the worst times, not the best. You'll want to literally prepare for the proverbial rainy day.


Paying for What's Free

The sun's rays are available to anyone for the taking, but it takes a lot of expensive equipment to turn them into power. Solar panels are the least-expensive form of renewable energy, but they still cost three to four times as much as traditional energy. If you're serious about making the switch, don't let that discourage you -- there might be ways to make it happen.

"Grid parity" is a term that's thrown around to describe one of the ultimate goals toward solar power sustainability -- when alternative sources of renewable power (which, in theory, includes other sources besides solar) will cost the same as traditional power. It's estimated that one of the milestones toward achieving grid parity is when the manufacturing costs for solar power infrastructure drop to about 65 cents per watt [source: Hutchinson]. Then, it can be sold at a profit for the companies, but it'll still be easier for homeowners to make the leap.


Before the housing bust, banks were known to lend a little extra to customers who planned to invest in efficient energy improvements and green technology, but it's a bit more difficult now to make such a case convincing. A "green mortgage" might still be an option for homebuyers who have good credit, and reliable numbers that demonstrate good research and commitment should help. A solid argument will show the bank how much the investment will save, and the time period necessary to recoup the costs.

Energy-related incentives and rebates vary so much, and change so frequently, that anyone considering a solar home conversion should take a close look at state-specific benefits. The right combination of grants, tax credits and per-watt rebates might make the initial investment more affordable than many homeowners think. As of 2012, the Energy Policy Act of 2005 still provides owners with a tax credit of 30 percent, or up to $2,000, in the year the system is installed. Beyond the short-term benefits, experts estimate that for every thousand dollars of annual energy savings, the value of your home will rise by $20,000 [source: Solar Energy World].

If and when you sell your solar-powered home, the investment should pay off big-time. Energy costs also vary by location, so living in a less-than-sunny state might still provide considerable benefits (where electricity costs so much that the savings are worth the investment, even if the house doesn't generate as much power as it would somewhere else).

As utility costs rise and your neighbors pay more for power, you might actually be entitled to a refund from your utility company. If your solar panels make more power than your house uses, you can sell your extra power back to the grid. Companies that install residential solar power tout this benefit as an easy way to recoup your investment, but of course, the results can vary widely (and the laws about this also vary depending on where you live). That's good motivation to pare down your family's energy consumption.

Some locales have made an effort to bring solar power to the masses. Berkely, Calif. and Boulder, Colo., have municipal solar programs, in which the city makes the infrastructure investment and recoups the cost through taxes. Other locales offer special loans that are paid back through additional property taxes. And at least one company has come up with a leasing program (kind of like leasing your cable box or satellite dish from your cable company), focusing on states that have particularly high energy costs to appeal to as many consumers as possible.

There is a dark side to solar power -- in some places, it truly isn't feasible. Germany has provided more than $130 billion in solar power subsidies, only to decide in 2012 that those benefits would be phased out. The infrastructure, they say, is too expensive and inefficient to use on a large scale, even if the sun's rays are free. The country's landscape and orientation might just be unsuitable to make the investment sustainable; experts figure that Germany's seemingly impressive solar initiative will have no effect on reducing global warming.

But if you don't live in Germany, the Netherlands, or any other country with notoriously short daylight hours, go outside and celebrate. If you want to convert your house to full solar power, it's probably possible.


Originally Published: Jun 19, 2012

Home Solar Panel FAQ

Can a house run on solar power alone?
It is possible to run a house on solar power alone. However, going completely off-grid requires a considerable financial and time investment. The higher your energy requirements, the more solar panels you'll need.
What are the cons of solar power?
Cloudy, overcast and rainy weather prevent the panels from collecting energy, making weather dependency the most significant drawback of solar energy. Another major con is the high initial cost, especially if you're going completely off the grid. Solar power is the cheapest form of renewable energy, but still four times more expensive than traditional sources.
How much do solar panels cost for a 1000 square foot house?
The number of solar panels needed for a house is not based solely on size, so no two 1000 square feet homes will be entirely alike. It’s easier to determine your solar panel needs based on your monthly electric bill cost and location. General guidelines recommend that homeowners install at least a 5-kilowatt system for a 1,000 square foot house with an average electric bill of $50-60 per month. The average cost per watt in the U.S. is $3, so a 5,000-watt solar power system would cost approximately $15,000. This does not account for important factors such as your specific location (and weather), roof orientation, type of house and available state and federal incentives and grants.
Why is solar power important?
Investing in solar power is important because it can reduce or eliminate the need for fossil fuels to produce electricity and power our homes.

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Author's Note: How to Run Your House Solely on Solar Power

I read a lot for this article (more than usual) because I got distracted by the chasm between practical solar homes and showpiece solar homes. In both cases, most solar-related technology innovations were pretty much what I expected. The extreme homes -- million-dollar mansions and such -- are fascinating and beautiful, and of course I'd want to live in one, if I could. The problem is, such design studies (and that's really what they are) don't serve much real-world purpose. They're aspirational, but the average person can't afford one. And if the average person can't afford a mansion that was designed to show off solar-powered capabilities, the end message is that the average person probably can't afford a solar-powered home.

That's unfortunate, because, after all, shouldn't the residents of a solar-powered house be interested in living more efficiently, in general? By which I mean, perhaps each resident does not need their own several thousand square feet. Even if a huge roof covering a huge house generates enough solar power to run off the grid, there are other resources being used inefficiently.

Not to judge the owners of solar mansions too harshly -- after all, such projects certainly generate positive publicity for the technology. But my interests found their way to the other end of the market, toward the homeowners or homebuyers who want solar power, but are forced to consider the investment, carefully weighing the benefits against the drawbacks.

I was surprised to discover that, aside from the initial investment as compared to traditional power, there really aren't any drawbacks. A solar system can be designed for almost any house and can run so smoothly that the owners will barely notice there's anything different. That's when solar power will truly be a success -- when it's the norm rather than the exception. It's hard to say how long it will take before we get to that point.

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  • Bryce, Robert. "Oil and gas won't be replaced by alternative energies anytime soon." Oct. 14, 2011. (May 14, 2012)
  • The Ecologist. "The solar powered house of the future?" March 4, 2010. (May 14, 2012)
  • Gross, Daniel. "When I reduce my home's energy costs, who should reap the benefit?" March 31, 2010. (May 14, 2012)
  • Hutchinson, Alex. "Solar Panel Drops to $1 per Watt: Is This a Milestone or the Bottom for Silicon-Based Panels?" Popular Mechanics. Feb. 26, 2009. (May 15, 2012)
  • Lewis, Bill. "Couple builds solar-powered home with help from Google." USA Today. March 17, 2011. (May 14, 2012)
  • Lomborg, Bjorn. "Why Germany is phasing out its solar-power subsidies." Feb. 18, 2012. (May 14, 2012)
  • Pandolfi, Keith. "The Scoop on Solar Power." This Old House. Aug. 4, 2008. (May 15, 2012),,20152332,00.html
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