Solar Panels Are Getting Better

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• Introduction
• The next generation of solar
• We're seeing the technology move into larger modules
• Efficiency isn't the whole story
• So should you wait?
• Conclusion

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Introduction

When I purchased my first solar panels back in 2008, they were still very expensive and considerably smaller than what we have available today. Over the years, I've seen and replaced some pretty old panels. Some of them looked quite unusual by today's standards and didn't produce much power at all. Back then, solar panels were expensive. I remember paying around $900 for a 135-watt panel. Some of my customers were paying over $1,000 for older 12-volt panels, and efficiencies were generally around 17%, sometimes a little better depending on the technology.

Fast forward to today, and things have changed considerably. This week I came across some pretty impressive developments in solar panel technology, and when you've been working in solar as long as I have, numbers like 35.5% efficiency definitely get your attention.

But there's a big difference between what a solar cell can achieve in a laboratory and what you can actually buy and install on the roof of your home today. So I decided to do a little digging and find out what's really happening. What I found is pretty exciting, but as always, there's a little more to the story than just the numbers.

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The next generation of solar

One of the technologies getting a lot of attention is called a tandem solar cell. The idea is to combine two different solar technologies rather than relying on just one. In this case, conventional silicon is combined with a material called perovskite. Each layer is designed to capture different parts of the sunlight spectrum, allowing the cell to convert more of the available sunlight into electricity than conventional silicon technology alone.

LONGi is making impressive progress on both fronts. In September 2026, the company announced a new world record of 28.29% efficiency using its HIBC (Hybrid Interdigitated Back Contact) technology. This is conventional crystalline silicon technology, not tandem technology. In July 2026, LONGi announced an even higher figure of 35.5% efficiency using a silicon/perovskite tandem cell. The two achievements are different because they use different technologies, but they show just how much research is going into improving solar efficiency.

Now, there's an important distinction when looking at that 35.5% figure. It represents the efficiency of an individual solar cell, not a complete residential solar panel. LONGi has also reported tandem modules reaching 31.4% and 29.4% efficiency, showing that the technology is moving beyond laboratory cells and into larger panels. However, achieving a record-breaking cell efficiency and producing a commercially available, reliable solar panel are two very different things.

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We're seeing the technology move into larger modules

LONGi isn't the only company working on this technology. Trina Solar announced a perovskite/silicon tandem module in June 2026 that reached 29.2% efficiency and 907 watts, with the results verified by TÜV SÜD. What's particularly interesting is that we're no longer just talking about small laboratory cells. Trina is working with an industrial-scale module format, bringing the technology another step closer to commercial manufacturing.

Oxford PV and Fraunhofer ISE have also demonstrated tandem modules reaching 25.6% efficiency across the entire module area. Their work included a 491-watt rooftop-sized module and a 546-watt bifacial module. These are much closer to the size and format of the solar panels we're familiar with today, rather than tiny cells being tested in a laboratory.

So there's definitely something happening here. Solar technology continues to move forward, and some of these developments could have a significant impact on the industry. But as exciting as these numbers are, there's another side to the story that we need to look at.

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Efficiency isn't the whole story

When someone tells you a new solar panel can achieve 30%, 35%, or even higher efficiency, it's easy to think, "Why wouldn't I wait for that?" That's a fair question, but efficiency is only one part of the equation. A solar panel installed on a roof has to survive years of exposure to the elements. It needs to handle heat, cold, moisture, UV exposure, wind and repeated temperature changes, all while continuing to produce electricity year after year.

This is one of the biggest challenges facing perovskite technology. The materials can be affected by moisture, oxygen, heat, light and electrical stress. Researchers are working on better materials, protective coatings and encapsulation methods to improve their long-term stability. That doesn't mean the technology won't succeed. Quite the opposite. There has already been enormous progress, and the potential is exciting. But achieving an impressive result in a laboratory is one thing. Having millions of panels sitting on rooftops and reliably producing power for 20 or 30 years is something else entirely. That's the part we still need to prove.

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So should you wait?

We don't know exactly when it will become commercially available at a price that makes sense for the average homeowner, or how it will perform after years of exposure to the elements.

Meanwhile, today's silicon technology is already very good. Technologies such as TOPCon offer excellent efficiency and are a practical choice for residential solar installations. We're also gaining more real-world experience with how these panels perform outside the laboratory. The National Laboratory of the Rockies, for example, continues to study the field performance and degradation of TOPCon and other solar panel technologies.

My thinking is simple: if solar makes financial and practical sense for your home today, why put off those benefits while waiting for a technology that may still be years away from being a proven, affordable option? Tandem solar is exciting, and I think it has a promising future, but there's still work to do before it becomes a mainstream residential choice.

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Conclusion

Solar technology has come a long way since I first started working with it, and it's certainly not finished evolving. Panels are becoming more efficient, inverters are getting smarter, and battery storage has changed dramatically. Tandem solar technology could be the next big step, especially for homes where roof space is limited. The 35.5% efficiency milestone is exciting, but there's still work to do before we know how reliable, affordable and practical these panels will be for everyday use.

For now, proven silicon technology remains a great choice for most residential solar systems. I'm always interested in what's coming next, but I believe in choosing technology based on what works best for your home, your needs and your budget, not simply chasing the newest numbers. Solar has come a long way, and I'm looking forward to seeing where it goes next.

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​Educational information only: This article is provided for general educational purposes and is not a substitute for site-specific professional advice. Electrical, building, safety, permitting, and equipment requirements can vary by project and location. Always verify requirements for your specific installation.

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