Uploaded April 2026 | Updated September 2026, 2 weeks ago
How This Heat Pump Water Heater is Also a Battery. Go to https://ground.news/undecided for an innovative way to stay fully informed on tech, energy, the climate and more. Save 40% on the Ground News unlimited access Vantage plan with my link. Heat pump water heaters have been around for over a decade. If you follow this channel, you probably know they're three to five times more efficient than a standard electric tank. Maybe you've got one. I do. But here's what most people don't realize. Even if you own a heat pump water heater, it's still pretty dumb. It heats reactively. The tank drops below the setpoint, the compressor kicks on. It doesn't know your schedule. It doesn't know your electricity rates. And it definitely doesn't know when your solar panels are cranking. Two Boston startups think that's a massive missed opportunity. They're treating the water heater as a thermal battery, a cheap, insulated vessel that can store energy as heat, shift electricity use to cheaper hours, and participate in grid services. One of them, Wilmington, Massachusetts-based Cala Systems, invited me to tour their factory. Their predictive software is licensed from the National Renewable Energy Lab. According to a California Energy Commission study, intelligent scheduling on time-of-use rate plans alone can cut costs by 15 to 19 percent beyond what a standard heat pump water heater already saves. So I went inside to find out: is a smart water heater actually worth the premium? Or is "intelligent" just a buzzword bumper sticker slapped on a tank of hot water?
Watch How the Worst Oil Crisis in History is Backfiring youtu.be/xC4v9tyxNgU?list=PLnTSM-ORSgi7uzySCXq8VXhodHB5B5OiQ
Video script and citations:
https://undecided.tech/how-this-heat-pump-water-heater-is-also-a-battery/
The Cala team has been following the discussion closely and noticed a couple of key points coming up repeatedly that are worth clarifying
Wi-Fi / “always online”
Cala does not rely on an internet connection to function - the core controls run on the unit itself. Connecting to Wi-Fi enables additional functionality like software updates, remote diagnostic support, app control, and heating coordination with solar, electricity pricing, and more.
Security / Remote Access
Remote diagnostics are opt-in - if you keep the unit offline, no data is shared. If you do connect, all sent data is encrypted and enables our technical team to more quickly detect, diagnose, and resolve any potential issues. There is no subscription and no fee for this functionality!
Get my achieve energy security with solar guide:
undecided.link/solar-guide
Follow-up podcast:
Video version - youtube.com/channel/UC4-aWB84Bupf5hxGqrwYqLA
Audio version - undecided.link/stilltbd-podcast
Join the Undecided Discord server:
undecided.link/discord
👋 Support Undecided on Patreon!
undecided.link/patreon
Visit my Energysage Portal (US):
Research solar panels, heat pumps, and more to get quotes for free!
undecided.link/energysage
For a curated solar buying experience (Canada)
EnergyPal's free personalized quotes:
undecided.link/energypal
👉 Follow Me
Mastodon
https://mastodon.social/@mattferrell
Bluesky
https://bsky.app/profile/mattferrell.bsky.social
Instagram
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Website
https://undecided.tech
Some music provided by Epidemic Sound
undecided.link/epidemic
I may earn a small commission for my endorsement or recommendation to products or services linked above, but I wouldn't put them here if I didn't like them. Your purchase helps support the channel and the videos I produce. Thank you.
Chapters
00:00 - Intro
02:10 - The Intelligence
05:21 - The Thermal Battery Concept
08:57 - The Tour
15:37 - The Real Economics
How This Heat Pump Water Heater is Also a Battery. Go to https://ground.news/undecided for an innovative way to stay fully informed on tech, energy, the climate and more. Save 40% on the Ground News unlimited access Vantage plan with my link. Heat pump water heaters have been around for over a decade. If you follow this channel, you probably know they're three to five times more efficient than a standard electric tank. Maybe you've got one. I do. But here's what most people don't realize. Even if you own a heat pump water heater, it's still pretty dumb. It heats reactively. The tank drops below the setpoint, the compressor kicks on. It doesn't know your schedule. It doesn't know your electricity rates. And it definitely doesn't know when your solar panels are cranking. Two Boston startups think that's a massive missed opportunity. They're treating the water heater as a thermal battery, a cheap, insulated vessel that can store energy as heat, shift electricity use to cheaper hours, and participate in grid services. One of them, Wilmington, Massachusetts-based Cala Systems, invited me to tour their factory. Their predictive software is licensed from the National Renewable Energy Lab. According to a California Energy Commission study, intelligent scheduling on time-of-use rate plans alone can cut costs by 15 to 19 percent beyond what a standard heat pump water heater already saves. So I went inside to find out: is a smart water heater actually worth the premium? Or is "intelligent" just a buzzword bumper sticker slapped on a tank of hot water?
Watch How the Worst Oil Crisis in History is Backfiring youtu.be/xC4v9tyxNgU?list=PLnTSM-ORSgi7uzySCXq8VXhodHB5B5OiQ
Video script and citations:
https://undecided.tech/how-this-heat-pump-water-heater-is-also-a-battery/
The Cala team has been following the discussion closely and noticed a couple of key points coming up repeatedly that are worth clarifying
Wi-Fi / “always online”
Cala does not rely on an internet connection to function - the core controls run on the unit itself. Connecting to Wi-Fi enables additional functionality like software updates, remote diagnostic support, app control, and heating coordination with solar, electricity pricing, and more.
Security / Remote Access
Remote diagnostics are opt-in - if you keep the unit offline, no data is shared. If you do connect, all sent data is encrypted and enables our technical team to more quickly detect, diagnose, and resolve any potential issues. There is no subscription and no fee for this functionality!
Get my achieve energy security with solar guide:
undecided.link/solar-guide
Follow-up podcast:
Video version - youtube.com/channel/UC4-aWB84Bupf5hxGqrwYqLA
Audio version - undecided.link/stilltbd-podcast
Join the Undecided Discord server:
undecided.link/discord
👋 Support Undecided on Patreon!
undecided.link/patreon
Visit my Energysage Portal (US):
Research solar panels, heat pumps, and more to get quotes for free!
undecided.link/energysage
For a curated solar buying experience (Canada)
EnergyPal's free personalized quotes:
undecided.link/energypal
👉 Follow Me
Mastodon
https://mastodon.social/@mattferrell
Bluesky
https://bsky.app/profile/mattferrell.bsky.social
instagram.com/undecidedtech
Website
https://undecided.tech
Some music provided by Epidemic Sound
undecided.link/epidemic
I may earn a small commission for my endorsement or recommendation to products or services linked above, but I wouldn't put them here if I didn't like them. Your purchase helps support the channel and the videos I produce. Thank you.
Chapters
00:00 - Intro
02:10 - The Intelligence
05:21 - The Thermal Battery Concept
08:57 - The Tour
15:37 - The Real Economics
