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Assessing My Home's Solar Potential: Step by Step

10/08/15

  01:37:00 pm, by Laurel Hamilton   , 1431 words  
Categories: All About Solar Power, Residential Solar, Ranting

Assessing My Home's Solar Potential: Step-by-Step

Run on Sun

Congratulations, you’ve decided to look into going solar!

Regardless of your reasons…be it economic, environmental, energy independence, or otherwise…it is a sad reality that not everyone can go solar. So how do you know if your property is even a good candidate? Of course, it is important to select a few different installers to do a professional assessment, but even someone with zero solar knowledge can learn how to do a quick preliminary assessment. Here are some simple steps to determining if your home may have a great solar powered future. 

1. My electric bills are killing me!

If your electric bills average $100 or under each month, solar probably won’t be more cost-effective than paying the utility. The costs for permitting, design and engineering all stay the same whether you buy a 3kW system or a 10kW system. Indeed, the labor required to install 5 panels and 10 panels is not very different since installers still have the same amount of electrical ground work. The installation of the actual panels is only a fraction of the total labor. Even the costs of products improves in bulk, so the bigger the system, often the better price per Watt you can get. 

Beyond this, there are many other things to consider such as whether you plan to increase your usage significantly in the future. But since utilities don’t want you to be an energy producer they won’t actually allow for more solar than your historical needs indicate… unless you plan to buy an electric vehicle. These are things you should discuss more in detail with your qualified installer.

2. My roof is perfect for solar…right?

In my blog piece “Roofing Reality Check”, I outlined the main things to consider when you examine your roof’s potential. Here are the highlights:

Steep Tile Roof

You could put solar here,
but it will cost you!

Space: First and foremost, to be a good solar candidate you must have adequate obstruction-free space for rows or columns of solar panels facing South, West, or East. The solar array must be three feet from any roof ridge or rake, and 18 inches from valleys to satisfy Fire Marshall guidelines. In addition, most panels are about the same size…roughly 65 inches by 40 inches. An average home in SoCal needs between 15-20 panels to offset their energy needs. This means that triangular spaces and roofs with many small faces are not going to work well for solar, but big open spaces with right angles are perfect. 

Pitch and Height: Labor costs go up when installing on more difficult-to-reach roof spaces. Second story and steeply pitched roofs both increase the overall cost due to the time and effort required to keep crews safe. If you have a very steep roof solar isn’t necessarily impossible, but it will affect the bottom line, and some installers may not feel comfortable at all depending on just how steep. If it looks like an Appalachian incline more than a Rocky Mountain then you should be safe. But if we’re talking summit of Mount Everest, you may have a harder time finding a competent installer who doesn’t run when he sees the pitch. 

Roofing Materials: The best roofing material for solar is composite shingles. Developments have been made to safely attach solar panels to metal and tile roofs but the cost for the racking attachments and labor are frequently higher. Run on Sun prefers to remove tile where the array will go, re-roof with composite shingles, install the solar, and backfill with remaining tiles. This incurs a re-roofing cost but is the safest way to avoid roof leaks and ensure safe attachment of the array to the rafters.

3. Solar’s arch nemesis…shade.

One of the first things an installer will do is take a quick look at a satellite image of your property to check for shade elements as well as the layout of your roof. A useful tool in the Los Angeles area is the LA Solar Map. This takes into account shading throughout the year and provides a handy report on your property’s viability for solar. It isn’t a perfect tool, however, so take a look around your property and note if there are any trees shading the roof spaces that you’ve identified as ideal for solar. Trees to the north would not pose a threat since solar will never be placed on a north-facing roof. But tall foliage to the south could negate any energy production value of a solar array. All may not be lost as microinverters, like the ones from Enphase that we feature on our projects, can do a lot to salvage a site plagued with shade. But even with this technology, 100% shaded areas are a non-starter. In addition to trees, note tall parapets on a flat roof, chimneys, satellite dishes, HVAC units, and second story walls which directly shade your ideal roof spaces.  

4. Can my electrical system handle it?

Full Center-Fed Panel

Center-fed panels, like this one, can be a problem for going solar.

This is something many people are uncomfortable with, but a quick glance at your main electrical service you can be very informative. First, find your main service. This should be located on an outside wall of your home with circular enclosed meter protruding out. Open up the main panel where you’ll find a column of breakers. The main breaker, the one with the largest number stamped on it, is either at the top or sometimes in the middle of the column of breakers. If it is in the middle, this is called a center-fed panel and you may need to upgrade your electrical service before going solar.

If you find yourself tripping breakers every time you turn on a hair dryer, that is also a sign you should upgrade your service. Even if you aren’t tripping, depending on the size of your home, if the main breaker is stamped with anything under 200 you may need a higher electrical service before going solar to avoid tripping in the future.

Next, take a look at the rest of the breakers. Does it look like the entire column is full? Sometimes there are rectangles in the metal face plate which can be punched out to add breakers when needed. If there is no space at all for a new breaker for solar, then you may need to upgrade your service. 

Unfortunately upgrading your service will add some cost. Ask your solar installer for their opinion but if any of the above rings true be prepared for this additional hurdle to sunshine power.

5. It’s all about the money…

The reality is, solar is an investment. While some companies may insist you can go solar for free, I would never count on getting something for nothing. We have outlined some of the myriad reasons we recommend avoiding zero-down solar leases in other posts like “Top 5 Reasons to Stay Away from that Solar Lease” and “The Perils of Solar Salesmen”. Frankly, the costs can more than double over time when you lease instead of purchase your system. 

So the last step to assess if you are a good candidate for solar is to assess your financial position. There are many low-interest solar loan options out there as well as property-assessed PACE financing, but in order to get the economic value of solar you need to be prepared to own the system outright. This way you can take the 30% federal tax credit and any additional rebates if available from your utility. 

To give you a ball-park idea of the cost for going solar in Run on Sun’s service area (LA Metro area) today, including design, labor, permit fees and the whole shebang, is roughly $4 to $5 per Watt. This means that an average house with a 5kW system will cost between $20,000 and $25,000 before rebates and incentives. Obviously the cost will be on the low end if you have a composite-shingle, single-story, low-pitched roof with no need for a service panel upgrade. Depending on your electric bills pre-solar, this investment can pencil out with a return in as early as year 5 or as late as year 10+. But deciding if the financial outlay is worth the long term investment is something you must assess before signing on the dotted line. 

 After going through the above steps you should have a solid idea of whether solar is right for your home or not. If you’ve determined its a go, the next step is to call your local installer and make sure they check all the same qualifiers and more. Now that you’re an expert on solar assessment 101 you can even suggest solar to any neighbors with homes that beg to be powered by the sun!

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Jim Jenal is the Founder & CEO of Run on Sun, Pasadena's premier installer and integrator of top-of-the-line solar power installations.
Run on Sun also offers solar consulting services, working with consumers, utilities, and municipalities to help them make solar power affordable and reliable.

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