21-07-2026
Solar panel technology has moved fast. If you're buying panels in 2026, you'll see terms like Mono PERC, TOPCon, HJT and HDT. This guide explains the difference in plain language — and why HDT sits at the top.
The panel technology ladder (simple version)
- Mono PERC — the older mainstream technology. Reliable, but lower efficiency than newer types.
- TOPCon — a newer N-type technology, more efficient than Mono PERC, now common in premium panels.
- HJT (Heterojunction) — combines crystalline silicon with thin-film layers. Higher efficiency, better performance in heat and low light.
- HDT (Advance HJT — Heterojunction Dual-side) — Devsol's advanced heterojunction dual-side technology, positioned a step above standard TOPCon panels.
Why HDT / HJT performs better in Indian conditions
India is hot. That matters, because every solar panel loses efficiency as it heats up. Heterojunction (HJT/HDT) panels have a lower temperature coefficient, meaning they lose less power on a hot rooftop than older panel types. In real terms: on a 45°C summer afternoon, an HDT panel keeps working closer to its rated output.
HDT panels are also bifacial — they generate power from both the front and the reflected light on the back — and use half-cut cell design to reduce internal losses and perform better under partial shade.
The Devsol 730W HDT Solar Panel
Devsol's flagship panel puts this technology into a single high-output module:
- 730Wp peak power
- 24.10% module efficiency
- 132 half-cut bifacial cells
- HDT (Advance HJT) heterojunction dual-side technology
- 35-year\* performance warranty (terms and conditions apply)
That combination — high wattage, high efficiency, and a long warranty — means fewer panels for the same output and more confidence over the life of the system.
Which panel is right for you?
- Budget-focused, small system: Mono PERC still works.
- Best long-term value, hot climate, limited roof space: HDT / HJT wins — more units generated per square metre, better hot-weather output, longer warranty.
For most Indian homes and businesses buying today, the higher upfront cost of HDT is offset by more generation and a longer usable life.
Explore Devsol solar panels
- Devsol Solar Panel range
- 730W 24V HDT Solar Panel (35-year* warranty)
- Pair with a Devsol hybrid inverter
Not sure how many panels your load needs? Contact our team or find a dealer near you.
*Written by Deepak Chaudhary, founder of Devsol Energy Pvt Ltd, with 17 years in solar and battery manufacturing.*