DeepBlue 4.0 420W
JA Solar's DeepBlue is the panel installers quietly recommend when budget is the deciding factor and the roof is not visually sensitive. The price-to-spec story is sensible, UK distributor support is reliable, and the measured output puts it within a few percent of the Longi flagship at a lower price per kWp.
- Efficiency
- 21.5%
- Running cost
- £-560/yr
- Installed
- £155 to £200 per panel installed
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Primary question · Is the JA Solar DeepBlue the honest value pick on a UK roof?
Budget-led installs on standard south or east-west roofs where every pound off the system price matters.
£155 to £200 per panel installed
- Honest pricing per kWp
- Reliable UK distributor warranty handling
- Solid measured output in British light
- Aesthetic is plain blue-on-silver in the entry tier
- Top-end efficiency trails Longi's flagship by a measurable margin
Open the cost planner to estimate your installed price.
Key specifications
- Power output
- 420 W per panel
- Efficiency
- 21.5%
- Temperature coefficient
- −0.30%/°C
- Product warranty
- 15 years
- , Honest pricing per kWp
- , Reliable UK distributor warranty handling
- , Solid measured output in British light
- , Aesthetic is plain blue-on-silver in the entry tier
- , Top-end efficiency trails Longi's flagship by a measurable margin
If your brief matches "budget-led installs on standard south or east-west roofs where every pound off the system price matters.", the DeepBlue 4.0 420W is a confident pick. If it doesn't, the alternatives above are more honest answers.
Estimate your installed cost
The planner uses your specific home; not a brochure number.