Turn your water heater into a hot-water battery
Make your water heater smart — so you don’t overpay
My water heater is 15 years old. I didn't replace it — I added ThermoSave. ~20% drop in water heating cost.
— Rudi, homeowner
Most homes save hundreds per year.
✅ Easy install, no plumber needed
✅ Always hot water
One of the few parts of your electric bill you can control.
Your water heater is costing you more than it should
Most homes overpay for hot water — because it runs during expensive hours.
Most homes spend $400–$700 per year on electric water heating — and it’s increasing
The second largest expense on your utility bill
What’s going wrong today
📈💸 Heats during peak prices
🔥⏳ Wastes energy when no one is using hot water
🌞❌ Misses cheaper, cleaner energy
ThermoSave fixes all three — automatically.
How it Works
Avoid expensive peak electricity
ThermoSave dynamically adjusts when your water heater runs, preventing costly heating as prices and usage change.
Store energy as hot water
Your water heater holds heat, so it doesn’t need to run constantly.
Use hot water as needed
Enjoy hot showers anytime — without changing your habits.
A typical electric water heater already stores ~10 kWh of energy as hot water.
Works with standard electric resistance tank water heaters (no plumbing required).
Easy installation
Install it yourself or have a local electrician help. No plumbing required.
1. Access the heater’s electrical connections
2. Mount ThermoSave and connect the wires
3. Finish setup and control it from the app
A straightforward retrofit for existing electric tank water heaters.
See and control your hot-water battery
Check status, switch modes, and set your schedule — all from your phone.
See whether your water heater is heating, idle, or paused — including live power usage so you know exactly what it's drawing.
📊 Status at a glance
Auto for everyday savings, Heat now for guests or extra demand, Away to pause heating.
🔘 Three modes for any situation
⏰ Peak hours to avoid
Heats less during your utility's expensive hours — and pause overnight to reduce standby loss.
Turn off water heating when you're away, and have hot water ready when you're back — no wasted energy. Perfect for vacations and between rentals.
✈️ Away mode
Built for people who want visibility, not guesses.
See if ThermoSave makes sense for you
Most homes save hundreds per year
See a quick estimate for yours.
Great for vacations, second homes, and rentals
Just like a smart thermostat, but for hot water.
Learn how Vacation Mode works →
Get ThermoSave updates — no spam.
Or Buy Now →
Start the savings
Easy installation
Install it yourself in less than an hour, or have a local electrician help if you prefer.
Automatic optimization
Uses your electricity pricing, learns your hot-water usage, and schedules heating when energy is cheapest — without manual setup.
Ongoing savings
Save without changing your habits, or follow simple suggestions to save even more. Many households save up to $1,000 or more over 5 years. Estimate your savings.
Summer launch pricing — $99
Now shipping — orders ship within 2 business days
Pay once, yours forever — no subscription, no monthly fees
Retrofits onto your existing electric resistance water heater in less than an hour
Time-of-use scheduling built in — shift heating to off-peak hours automatically
Control and monitor from the ThermoSave app (iOS & Android)
Flat $8 shipping across the US
2-Year Limited Hardware Warranty
30-day money-back guarantee
Who we are
ThermoSave is designed and tested in real homes — including our own.
We're a small team of engineers and product builders with decades of experience designing, shipping, and operating connected hardware used in homes and businesses today.
Our backgrounds span embedded systems, large-scale device fleets, cloud-connected products, and home energy — including systems that manage millions of devices in the field. We're starting anew with water heating because it’s one of the biggest, least visible energy costs in electrified homes, and one of the easiest to improve without changing how people live.
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Used in real homes
— Havard, family of 5
— Rudi, homeowner