If you could get free energy, would you do it? Of course you would! Free electricity, free natural gas and free heating oil or propane would make us all happy homeowners.

Only one of those is even remotely possible today, and that’s free electricity derived from the sun’s solar energy. But here’s the catch—unless you buy a home with rooftop solar panels already installed and working, rooftop solar power will cost you. Is it worth it? Follow along in this pro-and-con article and we’ll find out.

If you’re thinking about installing a solar power system in your existing home; or in the process of building an off-the-grid house or vacation cabin somewhere, you’ll definitely want to look at the economics of solar power. But first, even before you get out the calculator, you’ll want to stand outside your house and look up into the sky.

Cons:

1. Light Access

My wife and I once owned a home in sunny Southern California that we thought might be perfect for a rooftop solar installation—but we couldn’t make it work. Why? The peak of the roof of our house ran east to west, not the best alignment for maximizing solar panel effectiveness. If the peak of your roof runs south to north, then you’ll get the maximum amount of sun on both east- and west-facing planes of your roof during the mornings and afternoons.

2. Cutting Down Trees

We had a much bigger problem than roof alignment—we had trees. The solar contractor said “I can make it work, but you’ll need to cut down all these tall trees. Needless to say, we didn’t. It seemed ridiculous to cut down perfectly good trees in the name of environmental awareness. If you have foliage or a mountainside or a really tall building next door—anything that shades your roof—solar may not be a good option.

3. Cost

Initial buy-in cost. What does a good solar energy system cost? It depends. Taking into consideration the size of your house, the weather where you live and the cost of electricity in your area, you will typically need approximately 25-50 solar panels mounted on your roof (or a nearby piece of land with southern exposure), and the permits, inspections, and labor to make it all happen. That can cost anywhere between $20-75K, depending on all the above factors and on your energy needs. Big caveat: there are federal and state tax credits that can reduce your bill dramatically, and many states now offer big rebates, too. Some homeowners have cut the cost of their systems in half, or even more, by careful application of federal and state incentive programs.

4. Weather or Air Pollution

If you live in a place without ample sunshine, or in an urban area where the air quality is often poor, your solar energy generation capability may be severely compromised. A good solar contractor can tell you if that’s the case where you live.

5. Pay-off Horizon

How long do you plan to keep your home? On average, Americans move every five years, Europeans every eight. And on average, a solar energy system with the right capacity for a family home, and a battery backup system for emergencies, can take 5-10 years to pay back its initial cost with overall energy savings.

Pros:

1. The Earth 

Everyone who puts solar panels on their roof or their land makes a serious down-payment on energy sustainability, on reducing pollution and on mitigating climate change. Because the world’s nations tend to fight wars over dwindling fossil fuel supplies, you can even make the argument that solar panels contribute, in their own small way, towards world peace. In other words, the planet, and your grandchildren, will thank you.

2. Long-term Savings

If your new solar energy system has a ten-year payoff horizon, and you stay in your home for twenty years, you’ll feel pretty good about the initial decision in that second decade. If your system is tied in to the grid, your utility company will be paying you for the energy you return to the grid. And if you do sell your house, it will be worth more—homes with solar typically appreciate, depending on the size and components of the system, by $10-40,000.

3. The New Lease Deals

Want to avoid that big up-front cost? Companies in many states now offer no-money-down leases of solar energy systems. The solar company installs the panels, and you lease the system from them. (They also get to keep the federal and state incentives.) In many places the lease payments on a solar energy system can be more than paid for by the energy savings that result. Some of these lease deals are controversial—so you should read the fine print, and talk to at least a couple of reputable solar contractors, before you make a lease or buy decision.

4. Peace of Mind

Energy supplies fluctuate with world conditions. In an increasingly interdependent, globalized economy, few countries are energy self-sufficient, and trade battles, wars, political problems and other issues all have an impact on the availability of energy supplies. That changes the cost, and it seems like the prices for heating oil, natural gas and propane rarely go down—instead, they tend to rise. This means that calculating your long-term payoff horizon for a solar energy system, and basing it on today’s energy prices, might be misleading, and could favor the solar energy system much more (if you had a crystal ball). It also means that those with solar, if another energy crisis does occur, will be patting themselves on the back for their forward-thinking decision.

5. Silent, Maintenance-Free, and Guaranteed for 25 Years

Most solar panel manufacturers warrantee their panels and components for twenty-five years, and they require virtually no maintenance. Battery back-up energy storage systems, an option in most solar installations, will require some maintenance, but not much.

If you do decide to install a solar energy system, you’ll probably have one more advantage—the feeling that you’ve done something to generate a little energy.