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What to look for in solar systems

Bill Sepmeier and Matthew Charles
Vail CO, Colorado

EAGLE COUNTY, Colorado ” Years ago, Bill’s father gave him a sound piece of advice: “Never buy anything from someone you can’t sue if they screw up.”

The comment was made after the elder Sepmeier chose to not have their home’s driveway resurfaced for a remarkably low price by a crew of itinerate blacktop sprayers who were working in the area.

The logic is simple ” buying a good or service at a low initial price might end up costing a lot more in the long run. This holds especially true for renewable energy technology.



Energy systems involve careful design before a quote can be presented to a customer in good faith. For solar thermal (hot water) systems in particular, the considerations are nearly endless: How large is the demand for hot water or supplemental heat? What will be done with excess heat captured during the long summer days when demand is lower since no heating will be used?

During the first energy crisis back in the 1970’s, a lot of people with no training or experience with solar technology jumped into the solar industry looking for a quick buck.



Most of those systems were either promptly removed from the rooftops or unhooked and left to slowly die shortly after the customer realized they didn’t work. In most cases there really wasn’t anything wrong with the equipment ” solar thermal technology has changed very little throughout the decades ” it was the fact that the design and installations were poor. This caused solar energy’s first black eye and led to a widespread lack of faith in the technology.

Renewable energy would not become popular again in the US for another 30 years.

The popularity of renewable energy again today has not led to a mushrooming of unqualified firms in the field, but based upon our experience in the community over the past couple of years, it’s fair to say that there are growing reasons to be concerned about quality in design and installation.



Before accepting a design or quote from a solar contractor, check a few things:

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– How long has the business been around?

– What is the actual experience of the staff in renewable energy design?

– How many systems like the one planned for you have they installed?

– Do clients actually receive the predicted performance from their solar systems?

This last question is important. For example, a 2.5 kilowatt solar photovoltaic system should produce about 15 kilowatt hours per sunny day in this area, even in the winter and assuming a proper installation.

But if this system is mounted flush against a 6/12 pitch roof at our elevation it won’t produce much power at all for six months of the year since the array will be covered with snow most of the time. We see this design error happening around the valley all the time.

Other design problems ignore shading from dormers, chimneys and other rooftop obstructions. Even smaller objects such as pipe vents will cast long shadows to the east and west of the vent’s position when the sun is low on the horizon and cause problems. Even small amounts of shadow can reduce the power output of a photovoltaic array by as much as 60 percent or, if there is enough shadow, will nearly eliminate power production.

Renewable energy is a fantastic way to reduce your home’s monthly operating expenses, decrease the amount of greenhouse gasses that are emitted into the atmosphere, increase the value of your property, and hedge against the rising cost of fossil fuel based energy.

But without careful design considerations, your renewable energy system could end up performing poorly and defeat many of the benefits it should otherwise be able to provide. We should all remember the mistakes that were made in the past if we expect solar energy to be around for longer than it was the last go around.

Bill Sepmeier is chief technical officer and Matthew Charles is the design and sales manager for Grid Feeders in Eagle-Vail. Contact them at 970-688-4347.


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