Hi everyone,

Just wanted to share a setup I’ve been running at home that helps me automatically use my excess solar energy (PV surplus) to heat water, instead of exporting it to the grid for a few cents.

⚙️ My Goal

I wanted to make better use of the solar surplus during the day, instead of:

• Sending it back to the grid at low feed-in rates,

• Or wasting it altogether while my heater still runs at night on grid power.

🧩 My Setup

I'm using two products from IAMMETER:

• WEM3050T: A 3-phase Wi-Fi energy meter.
  → Tracks my solar generation, household consumption, and net export in real time.

• WPC3700: A Wi-Fi power controller for resistive loads (like my electric water heater).
  → Allows 0–100% output control, meaning I can modulate power based on how much solar surplus is available.

🧠 How It Works

1. WEM3050T sends real-time data about solar production and grid export.

2. I run logic (via IAMMETER Cloud or Home Assistant) that:

   • Calculates the current surplus;

   • Adjusts the WPC3700 output power to match that surplus;

   • So the heater only uses what’s available – no grid import!

3. If clouds come in or I turn on the oven – the heater auto-downscales its power.

No batteries, no complex setup, just clever energy shifting.

✅ Benefits So Far

• Higher self-consumption rate: now around 85–90%

• Noticeable drop in my energy bills

• No more running the heater overnight

• System runs 100% on auto, no manual switching

• Fully integrates with Home Assistant – I’ve set up a dashboard with energy flows

🔍 Who This Might Help

If you:

• Have solar and a resistive water heater;

• Hate wasting surplus PV;

• Want to avoid using grid power for heating;

• Like local or cloud-based automation...

...this could be a great low-cost improvement.

🔗 More Info & Docs

You can check the official use case here:
👉 https://www.iammeter.com/applications/pv-heater-control

They’ve got MQTT, API, and Home Assistant integrations too.

Let me know if you’re curious about the automation logic, MQTT setup, or HA scripts – happy to share more!

I'm interested! I try myself, but right now I am facing wpc3700 ha integration issues. Somehow ha "see" wem3080 but do not "see" wpc3700.

Hi,

Please post a new topic regarding your issue, and you can also attach the picture in your and circle the features you want to use (you mean that is valid in WEM3080 but not exist in WEM3700)