Add Solar to Your Home!

                                      EcoHomes Action for June, 2024


Our amazing sun!!


Evaluate your roof for solar and size an array to suit your energy needs. Reply to this email and tell us what you learn and you’ll be entered to win a STEM solar toy kit! 


The earth gets more solar energy in one hour than the entire world uses in a year.”    -Bill Nussey,


If that is not incredible enough, how about the fact that a single year of sunshine exceeds all known energy reserves of oil, coal, natural gas and uranium put together, as well as dwarfing every other kind of renewable energy.

(The figure below says it all. Thank you to SHC Solar Update)


We all know that the sun’s energy can be captured by the photovoltaic cells in solar panels. But, did you also know that the cost of solar has declined substantially in recent years? Combined with the 30% tax credit from the Feds, solar has become affordable for the average homeowner. Now, there is no “free solar” as the ubiquitous ads suggest*, but the monthly cost for a 10-year loan to finance your home’s solar array will be nearly comparable to your electric bill. (This depends on the variable cost of electricity). When the loan is paid off in 10 years, you will have nearly free electricity. 

One EcoHOMES participant has had solar panels since 2017 and is on track to pay them off in 8-10 years, depending on the cost of electricity. Depending on how long you plan to stay in your home, installing solar is a no-brainer. You potentially could have many years with minimal electric bills. Solar has been shown to increase the value of homes substantially without affecting your tax burden. 


This month’s action is to:

  1. Consider solar for your house
  2. Check 5 simple things to see if your roof is suitable for solar
  3. Estimate the appropriate size solar array for your house and its cost


Solar installers will give you a free site and cost evaluation but you can get a rough idea what they might tell you. 


There are 5 factors determining your roof’s suitability for solar:

  • Orientation – Use a compass or Google Earth to determine the orientation of your roof. Due south is ideal but there is a lot of wiggle room here. If you are 30 degrees east or west of south, there will be only a 3-5% reduction in annual energy output. Even a full east/west orientation is feasible with a 30% reduction.
  • Degree of Shading – Observe your roof at different times of day. Google Earth may be a helpful supplement to your own observations. When you are ready to get a professional estimate, solar installers have software to precisely determine shading.
  • Roof Pitch – A rule of thumb is that the ideal pitch is the same number as our latitude (43 degrees). The typical pitch for a cape is 12/12 or 45 degrees. 
  • Complexity of the Roof – If there are dormers or intricate gables, the number of panels you can install may be limited. Roof simplicity wins here.
  • Age of the Roof – The more expected life for your roof the better. It wouldn’t be advisable to install a solar array on an old roof, and then have to incur the cost of temporarily removing the panels in order to replace the roof. 


If you have adequate property, there may be a site for a “ground mounted array” with full control of the orientation, pitch and shading. However, expect to pay more for a ground mounted array.



If you have a good solar site, how big an array would you need and what would be the approximate cost?

  1. First get an old bill and figure your annual electrical use in kWh (with some add-on for anticipated EV and heat pumps in your future). 
  2. Divide the annual kWh by 1.3. This will give you an approximation of the size of the array you will need in watts. 
  3. Multiply this number by 2 for an approximation of the cost of the array. (The 30% federal tax rebate is included in this figure)
  4. Use an amortization table to give you your estimated monthly loan amount.
  5. Compare that amount with your electric bill. Remember the price of electricity is now ~$0.19/kWh. A year ago it was $0.27. Prices will continue to fluctuate, but when you own solar you are unaffected by the cost of electricity.

So get out there and capture a terawatt or two of sunshine!! There is more than enough to go around. Efficiency Maine has a partial list of installers. To that I would add True Enterprises, ReVision Energy, Maine Solar Solutions and LaPlante Electric, all local solar companies with excellent testimonials. 

Here are some interesting links for your perusal:

Energy Sage

PV Watts Calculator

(*The “free solar” claims that you see advertised generally mean the company owns the solar panels and you pay them).


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