A simple, wire-free way to track your solar water heater’s temperature and weather—no WiFi needed.
If you’ve ever had that frustrating moment standing under a cold shower, wondering if your solar water heater has warmed up enough, this story might resonate with you. I got tired of guessing whether my solar water tank was hot enough or if I needed to switch on the backup heating. So, I decided to build a solar water heater monitor that solves this exact problem, and it turned out to be pretty neat.
Why a Solar Water Heater Monitor?
Living with a solar water heater means you’re at the mercy of the sun. Mornings can be tricky if the cloud cover has been dense or if the tank didn’t heat up overnight. Instead of guessing, I wanted a straightforward way to check the status without running wires or depending on my home WiFi, which can be patchy at best. That’s when the idea of a wireless, locally displayed monitor became clear.
How My Solar Water Heater Monitor Works
The device I built measures the tank temperature directly with a PT100 industrial sensor, known for its accuracy and durability. Alongside that, it tracks outdoor weather conditions using the SHT30 sensor, so I have a better idea about the environment affecting my system.
But here’s the cool part: the data is transmitted via LoRa, a low-power long-range wireless tech. It’s super reliable—even through walls—and it doesn’t rely on WiFi or any internet connection. That means less hassle with network issues, no extra wiring to the roof, and you keep your data private unless you decide otherwise.
Indoors, an always-on e-paper display shows both the water tank temperature and current weather. E-paper is perfect here because it uses almost no power and is easy on the eyes. The battery life? Over a year per unit.
For the Tech Curious: Optional Cloud Dashboard
While I like keeping things local, there’s an optional cloud dashboard powered by Grafana for those who want alerts, historical data, or remote access. It’s not required, so if you prefer local-only setups, you’re good to go without any cloud dependency.
Thinking About Integrations and Features
I’m currently testing the setup, and it’s close to being ready for others to use. I’ve been thinking about integrating it with popular smart home hubs like Home Assistant, which would let you automate your heating systems further or receive custom notifications.
Also, I’m torn between focusing on enhancing the cloud dashboard or improving local features. Both have great benefits depending on your preferences for privacy and connectivity.
Why This Matters
This project isn’t just about tech for tech’s sake. It’s about adding a bit more comfort and confidence to everyday life. No more stepping into unexpectedly cold showers or wondering if it’s worth switching on the backup heater. Plus, it’s a neat way to better understand your solar energy system’s performance.
If you’re interested in building something like this or just want to learn more about LoRa and solar heating sensors, check out PT100 sensors at Omega Engineering and SHT30 sensor details at Sensirion.
For more on LoRa technology and how it’s used in home automation, Semtech’s site is a good reference: Semtech LoRa Overview.
This little project has made my daily routine easier and more predictable. Plus, it’s great fun to tinker with smart home tech that actually solves real problems.
If you’re curious about the idea or want to keep updated, there’s a demo video available and an early signup page for launch coming soon. Feel free to explore and maybe give it a try yourself!
Summary
Building a solar water heater monitor with an e-paper display and LoRa connectivity is a simple, effective way to keep tabs on your tank’s heat and weather conditions without WiFi or cloud dependency. It’s battery friendly, privacy conscious, and potentially very useful if you rely on solar water heating.
No more cold showers—just a bit more peace of mind.