What Is a Hot Water Divert and Should You Get One?

At Planet Blue Energy, we’re passionate about helping you make the most of solar power. One smart addition to many solar PV systems is a hot water divert, also known as a solar diverter or solar immersion diverter. But what exactly is it, how does it work, and is it right for your home? Let’s dive in.

✅ What Is a Hot Water Divert?

In simplest terms, a hot water divert is a smart device that captures surplus solar electricity and directs it to heat your hot water cylinder—rather than sending it back to the grid.

Solar panels often produce more electricity than you use, especially during sunny daytime hours. A hot water divert unit monitors this surplus and activates your immersion heater, heating the cylinder automatically, without any input from you.

 

🔧 How Does It Work?

The system typically uses two CT (current transformer) clamps:

1. One attached to your solar inverter (measuring generation)
2. One on your home’s incoming supply (measuring usage)

When solar output exceeds household demand, the unit sends the extra electricity to your immersion heater. Once usage rises or solar output drops, it switches off automatically.

You can also time your hot water heating, ensuring showers or washing cycles are covered—even if solar generation is low at that time .

 

👍 Top Benefits of a Hot Water Divert

1. Better use of your own solar power
   Instead of exporting excess electricity—often at a low tariff—you’re using it directly in your home.
2. Lower energy bills and carbon footprint
   By displacing grid-based heating, you reduce both costs and emissions. Up to 30% of electricity bills can go into hot water—so this is a significant saving.
3. Automatic operation
   Smart CT detection means it works without manual intervention—just install and forget.
4. Affordable upgrade
   At around €300–€500 (or £300–£500 in the UK), it’s a modest investment compared to battery storage.

 

⚠️ Considerations Before You Buy

1. You need an electric immersion heater
   If you lack this, the diverter has no load to drive.
2. Requires regular replacement
   As with most electrical devices, expect a lifespan of 10–15 years.
3. Solar-dependent
   On cloudy days or during winter, there may be insufficient surplus to divert—so diversions will be limited.
4. Close proximity needed
   Manufacturer guidance suggests keeping the unit and hot water tank within about 30 metres for best results.
5. Limited compared to batteries
   While cheaper, diverters only heat water—not power your whole home like batteries do.

 

🆚 Diverter vs Battery vs Heat Pump

• Hot Water Diverters: Heat water cost-effectively using surplus solar. Requires immersion heaters only.

• Battery Storage: More versatile—store solar for evening use across all household appliances. Higher upfront cost.

• Heat Pumps: Very efficient for heating, but perform differently. One unit of electricity can produce three to four units of hot water—or heating—via the heat pump requiring less overall energy input

For many homeowners, a diverter is a low-cost first step—especially if you already heat water electrically.

 

💷 Is It Worth It in Ireland?

Ireland’s solar environment means clear winter days are rare, but summer generation often exceeds household consumption—especially during peak insulation months.

• With export tariffs still relatively low compared to buying power, using surplus solar to heat water via a diverter saves more than exporting it and rebuying later .

• While smart meters and time-of-use tariffs can flip the economics in some cases, a diverter remains a straightforward, maintenance-light option.

Many of our clients at Planet Blue Energy have reported a noticeable reduction in electricity costs, especially during spring and summer. When paired with smart planning (like evening showers), the system maximises self-consumption while minimising grid reliance.

🛠️ Installation, Maintenance & Next Steps

At Planet Blue Energy, we offer comprehensive installation services—including full diverter integration with your existing solar PV system. Here’s what to expect:

• Pre-install review: Check immersion compatibility, proximity, cylinder type, and system wiring.

• Expert installation: Our certified electricians install CT clamps, wiring, and unit—integrated with your electrical board.

• Smart scheduling: We can also set timers for morning/evening heating to suit your routine.

• Ongoing support: Diverters typically last 10–15 years and are easy to replace—plus, we’re just a call away.

If you already have a battery or plan to install one, we’ll help you assess whether a diverter still fits—not always necessary if battery storage is preferred.

 

🌟 Final Verdict

Is a hot water divert right for you? At Planet Blue Energy, we believe it’s a fantastic, cost-effective upgrade for most solar households—especially if:

• You have an electric immersion heater

• You regularly see daytime solar surplus

• You want to reduce bills without committing to batteries

• You prefer a set‑and‑forget smart heating solution

If you’re considering an upgrade, chat to us! We’ll help you weigh the options and tailor a solution that maximises your solar investment.

Planet Blue Energy is committed to helping Irish homeowners harness the full potential of solar. Whether you’re interested in panels, a diverter, batteries, or just advice, we’re here to bring sunshine to your home—efficiently, affordably, and sustainably.

Ready to explore a hot water divert or solar upgrade? Get in touch today for a personalised consultation and quote.

 

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Ready to Make the Switch?

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