Hybrid heat pump water heater

Are the fans in these HPWH units 120v while the compressor is 240v? It could be that the on/off events are triggering on some 120v subcomponent and that’s why only half of the compressor power is being picked up? I just fired my GE Geospring up for the year. Waiting for it to be redetected, as I had to replace my monitor over the winter while the water heater was off for the season.

Edit: nevermind, these water heaters don’t have neutral connections. No 120v loads.

So, how are you using a 220v device on an HS110? I’ve seen this mentioned, but don’t know how people are (legally) doing this.

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Several sites have verified that the HS110 supports 240V @15amp max. I think this is because they are used in Europe with a different plug. I temporarily wired a plug and connector between the HW heater and the power supply so I could plug it in, and set it for Efficiency so the resistance heater isn’t envoked. I will put it all back at the end of the month, and I don’t advise doing this unless you are comfortable with working with home wiring. I installed the water heater, so I was familiar with the wiring requirements.

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They are not doing and staying within code. Anyone with the knowledge to rig it up is probably very well aware and using it temporarily

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Thanks. That’s helpful. I was aware that the European HS110’s and the US aren’t really different internally, just in plugs. But things like well pumps don’t “plug in”.

I’m an EE, and have done lots of wiring over years while renovating multiple old homes, but I’m also a strong believer in following the codes…both for safety and for insurance/legal reasons.


I wish someone had a product like the HS110 that could be direct wired inline to a circuit. I wired our Aquanta water heater controller myself. You wire it inline and it sits on top of your water heater over the power connection plate. In addition to providing a timer feature, it will automatically control temperature based on some adaptive algorithm that it uses to optimize the set temperature based on the history of your hot water usage. It also sends usage data back to Aquanta central so you can see your usage. It provides a useful benchmark for Sense’s estimate of usage. I’ve found it to be accurate ±15%.

OTOH, I doubt such a product would ever come to market because so few people would buy it.

Oh, another product I dream about is a connected power-monitoring circuit breaker. I think the big problem there besides space availability is that they’d have to make models compatible with each of the big circuit panel companies.

I suppose the most likely thing is that Sense becomes wildly profitable and they create an expansion model with extra current probe clamps for problematic circuits.

Neat device, Aquanta, thanks for mentioning it.

I too keep hoping that Sense, or perhaps Sense in partnership with TP-Link (who already has 240v monitoring…but with European plugs) would bring out a “direct wired in-line” module. Given the number of people that need to monitor such devices in the USA, I think this would actually have a significant market.

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Hey, I’d like to see that too! It is odd that in-line 240V smart plugs (even non-water heater specific) don’t exist. I’d imagine there are some code issues preventing it, as it does seem like a product with a significant market.

I sent the following to TP-Link marketing folks. Who knows what/if anything will happen?

I’m a current customer, in the USA, and I have a number of your HS110’s, some connecting to my Sense. One thing that I’d really like to be able to buy is a 240v version of the HS110 that is a module with wire lugs (or wire tails), rather than European plug/socket.

The reason is that many devices here in the US run on 220/240, and it’s not legal to hack something together with your European HS110 to monitor them. Following the device detection thread on Sense’s support site, it sounds like a bunch of other customers would also grab such a product, because Sense doesn’t detect (“sense”) these very well on its own.

Perhaps you could partner with Sense to market these in the US to their community?

Since you already have such capability, buried in your European HS110, it seems to me that this would be a fairly minor re-packaging effort, although I do suspect some code testing would also be required.

I’d be glad (and pay for the units) to be a beta tester ((-;).

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I don’t have space for any of the hybrid water heater models models but I was tempted to explore the Nyle retrofit heat pump (discussed here) … which no longer seems to be available (small ones at least). Anybody have something like that?

Still no detection here. Sense mistakenly detects the heat pump startup as the pool pump.

Has anyone had any success with discovery and monitoring of Heat Pump Water Heaters? My AO Smith HPWH was discovered when I installed it a year and a half ago and reported half of all usage (one phase only) for almost a year. I put it behind an HS110 for awhile to get accurate readings, which I submitted to Sense, but ever since I disconnected the HS110, it has not been rediscovered. For 5 months I’ve been asking Sense why it is not reporting, but all I get is that it is hard to detect when it shuts off. I wonder if anyone else is having better success.

Inverter-based heat pumps all present similar challenges to Sense. Some people have reported success recently with “ramping” devices so I think detection is improving. If I were you I would leave the HS110 on there.

Recent example:

Do you run the tank in heat-pump mode only or is it activating the heating elements when called for?

It’s being run in heat pump only mode, but the resistance heat has kicked in a few times and was recorded. Over the last year I’ve deleted this device several times on Sense Support’s advice, but have seen no substantial improvements in detection. And on rare occasions I do see brief reporting, but it is irregular. Their models don’t seem to be able to process these types of devices, and I don’t know if there is a future solution unless they can change their model.

I have a GE Geospring hybrid (running on HP-only mode) and it actually got detected quite quickly and it’s very reliable. So, it can happen! And no, I don’t get any special treatment because I work here :slight_smile:

Still, as @Ixu notes, heat pumps in general can be a challenge.

I’ve merged this thread into the larger HPWH thread.

Would be interested to know if the resistive element heating helps ID these when in heat-pump mode … in the same way that I assume a defrost element in a fridge could help ID the existence of a fridge and the correlated compressor, fan & light cycles.

e.g. In a simple case a house with a HPWH and an inverter-based AC unit of similar size might be seen by Sense as one or two AC units until, bingo, the resistive heating element goes on and becomes a reliable indicator that there is an HPWH in the house and thus gives more weighting to that detection possibility.

As the dataset expands, I assume those longer cycles and larger scale events start to emerge vs the shorter “ons” and “offs” that Sense has an easier time with.

Update: I’ve turned my HPWH off for the season as the boiler has now been started up. Sense did detect the water heater, and does so quite reliably, but it only detects half of its usage. I contacted support, and they confirmed that the device model is only detecting one phase of the usage. This is a GE Geospring unit that operates in heat pump mode 99% of the time. It only used the resistive elements once this year.

I haven’t assembled the data properly yet and this graphic is certainly lacking clarity (please don’t look too hard) but with my dual-Sense setup and dedicated CTs on my regular non-HP HW tank there is also evidence of a single phase only bias … the timing though for native detection looks spot-on with the resistive element …

I was wondering if my Rheem hybrid hot water heater was my mysterious 'motor1". I installed it back in April and I always run it in heat pump mode , it’s a 50 gallon model and I know people say they have a long recovery but in a three family household we haven’t had any issues. I switched it over to resistive mode yesterday just to run it for the week like that and see how much more electricity is uses based on the econet app. When it kicks on my notes say the dryer came on but then the power usage goes into other. As for those using an hs110 to power something like a water heater I would make sure it’s only in heat pump mode but then again I wouldn’t do it anyway. I have a switch wired up out by the water heater. Plus after seeing a couple of hs110 on Amazon that had burning issues I would be pretty hesitant to modify one and use it for anything higher-powered.

I would absolutely NOT modify a US HS110 for 240 v use. They are not US certified for such use, so doing that violates both electrical codes and homeowners insurance.