Immersun
Immersun
One of the original UK solar diverters — handles multiple loads (immersion + secondary). More flexible than single-load alternatives for homes with more complex needs.
~£249 + installation
How it scores
Scores based on published manufacturer specifications and weighted criteria — not lab testing. Methodology.
Specifications
- Wifi
- No
- Phases
- 1
- Load type
- immersion
- Max power w
- 3600
- Warranty years
- 3
- Compatible with
- solar, battery
What I noticed
Immersun is one of the longest-standing products in the UK solar diverter space. Its main differentiator is the ability to manage two separate loads — typically an immersion heater as the primary and a secondary load (underfloor heating, towel rail) that cuts in once the primary is satisfied. This avoids wasting solar surplus when the cylinder is already fully heated.
Who it suits
Homes with a secondary resistive load that could usefully absorb surplus solar beyond what the cylinder needs — particularly relevant in summer when the cylinder heats quickly and surplus continues through the afternoon.
Watch for
No app or remote access. The dual-load setup requires two separate circuit connections. Installation is slightly more involved than single-load alternatives.