Search this site

News & Events

Why do I want thin film solar? Aren't the glass-faced crystalline panels better?

That depends on how you define better. Crystalline PV panels do have a higher efficiency rating. BUT that is misleading. Because of the nature of crystalline cells, the higher efficiency can only be fully realized when the panel is pointed directly at the sun.

Thin Film panels, while not as efficient on an inch-by-inch basis, will harvest a greater amount of solar energy on any given day than their crystalline counterparts. This overall efficiency is a large part of what makes Thin Film a superior solar panel for use on roofs.

Thin Film solar will generally produce 10-15% more usable power per year than an equivalent crystalline system and are especially superior in low light conditions - think cloudy days.

It is true that for a similarly rated system Thin Film solar panels will take up more space than crystalline. But since roof areas tend to be large, this is a difference that makes no practical difference.

Is Thin Film more expensive?

No! Thin Film solar generally costs about 20% less than crystalline solar for a similarly rated system.

Thin Film solar usually does not require additional racks to be mounted on. This not only saves in material costs but also in labor costs.

I was told that the adhesive used to hold the panels to the roof has been changed several times over the years. Why is that?

There are several reasons. But none of them have to do with the adhesive failing to hold up.

Product improvement is a normal activity for manufacturers. And making improvements to the adhesive used on Thin Film solar panels is no exception. One reason for this improvement is to use a more environmentally friendly formulation. Another is to help reduce costs. And the manufacturer has been very attentive to ideas put forward by installers and has incorporated many of these ideas into their product improvement cycle.

How durable are Thin Film panels?

Thin Film solar panels are very durable. You can even walk on them. The material is flexible and this helps the panels survive impact damage. Hail, wind blown branches and other debris, can more easily damage the glass front of crystalline panels. And in the unlikely event a panel was damaged, Thin Film panels will show only a slight drop-off in power while a crystalline panels can drop-off 50% or more in output.

What about shading? Doesn't shading really cut back on power?

Any time you shade a solar panel you see a drop in power production. How big a drop is the important thing to consider.

A fist-sized shadow on a crystalline panel will cut it's power output by 30% or more. The same shadow on a Thin Film panel will result in a 4 - 5% power reduction. Put another way, a single wet maple leaf can cut 30% of the power of the more expensive crystalline panel while only robbing 5% from the less expensive Thin Film panel.

You're putting these on a roof. Don't the high summer temperatures on a roof greatly reduce the power that gets made?

You're thinking crystalline here. Crystalline panels will drop off as much as 16% when they get hot. This is why they are mounted above the roof - so air can get under them to help keep them cooler.

Thin Film panels will only drop off 4% in power under the same heat conditions. And they don't need to be elevated above the roof. The standing seam metal Kulp's manufactures and installs acts as a heat-sink to help keep the Thin Film panels cooler.

How much power can I really make?

That depends on a number of factors, including: How big a system can fit on your roof, how much you want to spend on the system, and if the area will be shaded by trees or other objects.

A typical 2 kilowatt system will produce approximately 2779 kilowatt hours of usable power in an average year. A system of this size costs around $17,000 to have installed. A 5 kilowatt system will produce about 7000 kilowatt hours of usable power per year and costs around $35,000.

So how does a solar electric system pay for itself?

Solar electric systems are longer-term investments. Because the systems are designed to operate for at least 25 years, it is important to look at the return on investment in that same 25 year time-frame.

The current Federal tax credit is 30% of system cost. This credit is available through 2016. The State of Wisconsin, through the non-profit organization Focus on Energy, is offering a cash back reward that is based on system size and performance. Here is a typical example:

5 kilowatt rated system with a projected annual power production of 7000 kilowatt hours per year -

$35,000 Upfront cost

$10,500 Federal Tax Credit

$ 7,000 Focus on Energy Cash Back

--------

$17,500 Final System Cost

50% of the system cost comes back to you almost immediately. The remaining 50% will typically be paid off in the form of produced energy within the first 11 years. This leaves 14 or so years of pure profit for the system owner. A typical internal rate of return on this investment is in the neighborhood of 8 - 9%. This rate of return far exceeds a CD or a Federal Treasury Bond for the same investment. And it's tax free.

Tax Free?

Current Wisconsin law excludes alternative energy systems from sales tax. Another law excludes the system from property tax so your property tax bill won't rise just because you had a solar electric system installed. And lastly, so long as you produce somewhat less total power than you use there is no income tax on the value of the power you produce.

Sales tax free. Property tax free. Income tax free.

Where can I see one of your installed systems?

At Kulp's we respect our customer's privacy, so we don't list each and every home or business. Some of our solar electric customers have graciously agreed to have their homes listed for you to drive by and look at. Please contact Kulp's of Stratford at 800.285.2917 and we will point you to a system near you. Or feel free to use our contact page here on this site to request this information.

picture gallery

800.285.2917

solar@kulpsolar.com