Quality vs Quantity | Solar Module Efficiency

Solar Efficiency

In all things in life, when buying a product, you have to make a choice.  Sometimes these choices take a bit of research, confidence, and a smidge of gut instinct.  

Solar modules are not boxes of cereal (read: there are a handful of reputable brands, they are expensive, and the differences matter).  They are power generators performing a very important and useful function.  There is a cost and there is a personal relationship with them.  They will be with you much longer than your car, pet, and hopefully your mattress.

How Important is Efficiency?

The bottom line on the benefits of high efficiency modules is the PV system’s footprint.

Most of the solar power systems we install are undersized for how much usage there is.  There simply is not enough space to install enough panels to zero their bill.  Your unshaded, unobstructed, mostly South facing roof space is the limit to how many solar modules you can fit on the roof.  

Don’t get me wrong, if you are working with a creative solar installer you can pole or ground mount, or even awning mount off the roof, but the reality is the home roof is the best place on most properties.

How Can I Get My Bill Closer to Zero?

The only way to squeeze a little more juice out of the “fruit” is to buy higher efficiency panels.  By buying higher efficiency panels you can fit more in the same space.  

The extra cost of these modules is offset by needing fewer modules to do the same work as less efficient ones.  The current best efficiencies are in the 16-20% range. Here’s a quick calculation to illustrate the point:


Average Home Consumption:

320 W panels x 24 modules = 7680 W
265 W panels x 24 modules = 6360 W

7690 W (high efficiency) – 6360 W (lower efficiency) = 1320W difference in the same space. That’s like having 4 extra panels in the same space.


Caveat: If you have room to spare on your roof and in your yard, you still want to limit the PV system size proportionally to your power consumption. Net Metering in Illinois allows you to sell electricity back to the grid in kWH, but they don’t want your excess.  Any bonus energy you’ve made is gifted to the grid.  

This is a lovely gesture, but you also want to be fiscally smart about it.  To make sure your altruism isn’t a blinding light, utilities will only give you a net metering agreement if your system is within a 5% margin of your past annual usage.  

One last thing to consider is you can go bigger if you convert traditionally gas-powered appliances to electric. This included water heaters, cooking ovens, and heating.  There are rebates from utilities to offset their cost, and you will be one enormous step closer to energy independence.

LG modules | 2 NeON 320 W | 19.5%
Solarworld | 265 W | 15.81%

How Important is Buying from an Established Brand?

Ever hear of a company called Yugo? What about Linens-N-Things, AOL, Foot Locker, etc., etc., etc.  Even globally recognized brands can disappear.  

With a photovoltaic system you are investing in a life expectancy of 25+ years.  If you carpet your roof in off-brand modules and they fail, you expect to fall back on the manufacturer warranty.  These warranties are only as good as the company backing them.  If that company no longer exists then you have little more than roof art and regret.  

Rethink Electric is always on the cutting edge of solar technology, and we only use reputable, reliable manufacturers that have corporate longevity.

Bottom Line: Trust Your Solar Installer

Every system is unique like a fingerprint. There are so many variables that guide your custom design.  

The Rethink Design team always recommends a reputable brand that is durable, has a great efficiency, and is at the right price point to lower your Return On Investment.  

As technologies change, so do our recommendations.  We are always up to date on the latest developments from roof mounts and racking to module durability and efficiency.  We stake our reputation on every system we install, and it will be the very best solution for our customers.

Share this Post:

Share on twitter
Share on facebook
Share on linkedin

Post Categories

Newest Posts