Bill Haman, P.E.
Program Manager

A registered professional engineer in Iowa and Wisconsin.

  • over 30 years of engineering experience in both the public and private sectors
  • industrial programs manager
  • Alternate Energy Revolving Loan Program manager since 1996

Would putting solar panels on a small porch roof make sense and be eligible for tax credits?

The viability and economics of any renewable energy project are very site specific.  The orientation of the solar array is particularly important and a southerly oriented solar array should generate the maximum energy at the site.  Other factors that are very important to the system performance include the tilt angle of the modules (normally the pitch of the roof on roof mounted arrays) which is optimized at about 30 degrees, the magnitude of shading that the array would be exposed to (the neighbors existing tree may be a large detriment to the overall performance of the array), the level of soiling experienced by the array (dirt, leaf accumulation, bird droppings, etc.), and the equipment design.

The economics of the solar array are dependent on the net cost of the system, the energy generation of the array, and the value of the energy generated by the array (comparable to the retail price offset from the utility company in a net metering tariff).  A simple cost benefit analysis using the above factors can provide a basis for determining whether the investment makes sense for you.  Incentives, such as Federal and State tax credits, can improve the economics of the project.  As a homeowner, you would be eligible for both credits (currently the Federal tax credit is 30% of eligible costs and the Iowa credit is 60% of the Federal credit).

One of the advantages of solar energy is its modularity.  Constructing an array in increments is a viable approach for situations where capital for investment is limited or where the ideal array size is uncertain because of nonexistent electric usage history or an expected increase in future electric usage needs.