Interesting but federal tax credits for heat pump water heaters is ending next month [1]. It looks nice though.
For people wondering what's up with the "150 gal virtual" capacity, it's actually a 47 gal water heater but it heats water to a really high temperature (if needed) and mixes it with a thermostatic valve to output the desired temperature. For example if cold water was 15 degrees C and you want the hot water to be 40 degrees C, it can triple its "capacity" by heating it up to 90 degrees C and then mixing one part hot water with 2 parts cold water to give you three times as much hot water. Of course, this comes with a grave penalty to efficiency so you should only do it for "party mode".
They must be doing something different to get that much capacity. There’s a bunch of water heaters with mixing valves but they don’t talk about that much capacity. What worries me is, doesn’t higher temperature make your tank rust faster?
I had one of these types of water heaters in an old apartment. Thing worked kinda okay-ish? The main issue was that it was electric and if you used the hot water for really any time at all (bath, dishwasher) then it would pop the fuse from current draws and overheating. Likely this was some issue with the water heater and the electrical system of the apartment.
Still, really annoying when half way through your bath, the fuse would pop, colder water now coming out, and you'd have to completely dry yourself to reset it and wait for whatever got too hot to cool down enough to get the other half of the bath going again.
Sounds like you're using a totally different type of water heater (tankless) and not a heat pump water heater (which has a tank, so even if the fuse pops, the water won't get cold instantly).
Why do you care what size it is though? It's only the capacity that matters. For example a tankless only has a few gallons inside, but that doesn't limit how long of a shower you can take.
The pricing page does not make it clear how much the actual unit costs, just $6500 with installation. Never purchased a water heater, but going to Home Depot, I see traditional options priced $500-$2000.
Which says you are putting up a high upfront cost, hoping to recoup on increased efficiency. Which could be worthwhile, but you would have to run some simulations if the price is worthwhile. Seems potentially easier to get a dumb water heater to run extra hot using off-peak electricity.
I don't expect this unit to be much more efficient than a $1800 home depot heat pump water heater. On the other hand, installation seems to include a hot water return line and return pump (the pump itself would be another $300 on home depot), and I've been quoted around $1000-2000 in labor to install plumbing like that.
These data mining companies really take us for chumps.
Pay EXTRA for a water heater that collects data on when you shower, how much water you use, and at what temperature, so that they can sell that that to someone who wants to serve you a towel ad on your smart fridge screen after you get dressed.
The best investment in my comfort and upgrading my home was two redundantly configured Navien continuous water heaters.
Never worry about running out of hot water ever again. If I’m gone on a trip for 2 weeks my hot water bill is zero. Due to having overcapacity, whenever I have guests staying with me no one ever has to worry about simultaneously using showers or any other hot water at all. I run out of water pressure before I do heating capacity.
If one breaks I just schedule a repair or replacement for weeks in advance and have to limit folks to 2 simultaneous showers at any given time. Hasn’t happened yet.
I will never go back to a tank based water heater unless outright forced into it. It’s one of those “TiVo like” upgrades to your lifestyle you never knew you needed until you have it.
Certainly not cheap, but also not prohibitively expensive if you can find a competent installer who doesn’t overcharge.
> If I’m gone on a trip for 2 weeks my hot water bill is zero
You mention other advantages, but money isn't one. You're limited to 100% efficiency with tankless.
Although an idle hot water tank can waste ~70W (~1.7kWh) of power, this is way more than made up for by using a heat pump. Plus tankless strains the grid a lot more than any system with a buffer built in.
Recirculating works fine with these, if I chose to do it. They both have a tiny hyper-heated insulated tank for the purpose so they can trickle a hot water loop to the furthest destination. They also have a recirc mode which would barely show up on your monthly energy bill.
If I was building new construction I’d do it, but the upgrade just isn’t worth it for me at the moment since it would require drywall repair and running another return line for relatively minimal benefit.
Note as others have pointed out: this setup is not to save money, it’s entirely quality of life as the primary metric under consideration.
Is this unusual in the US? I think almost everyone in the UK for years has been installing ‘combi’ boilers, which are ones that heat the water in radiators and also heat water on-demand.
In my geographic area (coldest part of the lower 48 that isn’t an mountain) everyone heats water with natural gas which is cheap as hell anyways so we all have tank style water heaters.
A heat pump water heater seems like a no brainer way to improve efficiency.
They're not yet common, but there are many more options available over seas than in America.
This project seems emblematic of the challenges facing funding manufacturing initiatives in America.
What's funded are the projects that appeal to tech investors, more of a focus on flashy presentation, luxury design, AI, and cloud app features, than the baseline functionality.
We get innovation as a side effect of convincing investors that the idea will disrupt industries and create app ecosystems that lock in consumer attention.
Chasing the 100x unicorns and no longer training workhorses
Big problem in the US is that in many regions natural gas is cheaper than electricity, causing heat pump water heaters to be more expensive for the consumer. So everyone ends up burning more.
That doesn't make a lot of sense. A modern gas-fired plant is ~50% efficient and heat pumps typically have a COP of ~3 for hot water, so if you take natural gas, burn it to convert it to electricity, then feed that electricity to a heat pump, you'll get ~1.5x the energy you'd get if you just burned the natural gas.
Maybe the problem is shared deeper than that, that both industry and individuals are not interested, incentivized, or capable of investing into improving on good enough.
It can misses some sensor readings, boil the water and scalds the user "automatically". Dumb heaters requires the user to "manually" do this, they never do though.
P/S: I'd prefer your stop working scenario
Technology Connections have a video about how water heaters work in detail and how much power can be saved by strategically turning them off when not needed.
There's several layers of humor in TC videos, the cringe joke, the acknowledgement that "I'm making a cringe joke", the acknowledgement that the joke is still lame with the meta-joke, the "well I put it in the video anyway, aren't I funny?".
But the end result makes me cringe after all.
Edit: oh, you're talking about this product website...
One thing I learned from the video was how do water heaters get away with giving higher capacity numbers than they actually have. Well, apparently, kind of like air, hot water also rises and the heater keeps working while in use and it also has secondary heater element it can switch to, so it can follow the cold-hot water separation line.
There are systems (like the sanco2) that use an indoor/outdoor pump.
> This sounds terrible for efficiency in winter, as you will need to reheat the room
Sure, but lots of people have some point of the year they want cooling.
Even during the heating season it's only worse if you're heating the living space with something _worse_ than what you're using to heat the hot water. If you have a heat pump for room heat then you're moving heat from outside, to in the house, to in the water heater.
If you're heating the room with electric then in the winter it's no different than using an electric water heater (100% efficient).
Where does it day that? Would be great if it chose inside or outside based on target inside temp (e.g. cools indoor air in summer to heat water for washing and showers)
Looking at pictures it must pull heat from ambient air or from electricity. There is not enough tubes to have interior and external heat exchanging units.
Readit News
For people wondering what's up with the "150 gal virtual" capacity, it's actually a 47 gal water heater but it heats water to a really high temperature (if needed) and mixes it with a thermostatic valve to output the desired temperature. For example if cold water was 15 degrees C and you want the hot water to be 40 degrees C, it can triple its "capacity" by heating it up to 90 degrees C and then mixing one part hot water with 2 parts cold water to give you three times as much hot water. Of course, this comes with a grave penalty to efficiency so you should only do it for "party mode".
[1] https://www.energystar.gov/about/federal-tax-credits
Yeah, they put the word 'virtual' in front.
Still, really annoying when half way through your bath, the fuse would pop, colder water now coming out, and you'd have to completely dry yourself to reset it and wait for whatever got too hot to cool down enough to get the other half of the bath going again.
The thermostatic valve makes it so that the water that comes out of the water heater is at a more reasonable temperature.
Which says you are putting up a high upfront cost, hoping to recoup on increased efficiency. Which could be worthwhile, but you would have to run some simulations if the price is worthwhile. Seems potentially easier to get a dumb water heater to run extra hot using off-peak electricity.
Pay EXTRA for a water heater that collects data on when you shower, how much water you use, and at what temperature, so that they can sell that that to someone who wants to serve you a towel ad on your smart fridge screen after you get dressed.
Never worry about running out of hot water ever again. If I’m gone on a trip for 2 weeks my hot water bill is zero. Due to having overcapacity, whenever I have guests staying with me no one ever has to worry about simultaneously using showers or any other hot water at all. I run out of water pressure before I do heating capacity.
If one breaks I just schedule a repair or replacement for weeks in advance and have to limit folks to 2 simultaneous showers at any given time. Hasn’t happened yet.
I will never go back to a tank based water heater unless outright forced into it. It’s one of those “TiVo like” upgrades to your lifestyle you never knew you needed until you have it.
Certainly not cheap, but also not prohibitively expensive if you can find a competent installer who doesn’t overcharge.
You mention other advantages, but money isn't one. You're limited to 100% efficiency with tankless.
Although an idle hot water tank can waste ~70W (~1.7kWh) of power, this is way more than made up for by using a heat pump. Plus tankless strains the grid a lot more than any system with a buffer built in.
1. Can’t have recirculation pump to supply hot water instantly throughout the whole house.
2. Significantly higher energy bill compared to heat pump.
An additional bonus is the heat pump cools my garage in the summer.
If I was building new construction I’d do it, but the upgrade just isn’t worth it for me at the moment since it would require drywall repair and running another return line for relatively minimal benefit.
Note as others have pointed out: this setup is not to save money, it’s entirely quality of life as the primary metric under consideration.
This project seems emblematic of the challenges facing funding manufacturing initiatives in America. What's funded are the projects that appeal to tech investors, more of a focus on flashy presentation, luxury design, AI, and cloud app features, than the baseline functionality.
We get innovation as a side effect of convincing investors that the idea will disrupt industries and create app ecosystems that lock in consumer attention. Chasing the 100x unicorns and no longer training workhorses
The last "intelligent" systems that made sense to me in the home are variable speed HVAC and micro grid / solar / battery stuff.
What is the value add to the customer of making hot water an app that can presumably stop working the next time AWS goes down?
https://youtu.be/Bm7L-2J52GU
However, the website has some weird vibes as well, like why would you say something like below?
> And some just want Dad Mode for when your teenager needs to finish that shower.
But the end result makes me cringe after all.
Edit: oh, you're talking about this product website...
One thing I learned from the video was how do water heaters get away with giving higher capacity numbers than they actually have. Well, apparently, kind of like air, hot water also rises and the heater keeps working while in use and it also has secondary heater element it can switch to, so it can follow the cold-hot water separation line.
> This sounds terrible for efficiency in winter, as you will need to reheat the room
Sure, but lots of people have some point of the year they want cooling.
Even during the heating season it's only worse if you're heating the living space with something _worse_ than what you're using to heat the hot water. If you have a heat pump for room heat then you're moving heat from outside, to in the house, to in the water heater.
If you're heating the room with electric then in the winter it's no different than using an electric water heater (100% efficient).