Anyone else think this is a little funky? Claiming $200 a year savings for the average homeowner seems very questionable.
@pswired I saw this when I logged in this morning. Double-checking the source information here. If it’s inaccurate, we’re going to pull it down and adjust. Thanks for keeping us honest - we’re usually pretty good about data sourcing.
Some basic math:
High efficiency electric water heater is around 0.95EF
This one claims 0.99EF (I guess)
i.e. 4% saving.
If 4% of your bill = $200 then your bill needs to be 25 x 200 = $5,000 or more per year for that to make sense.
And that’s assuming all you are doing electrically is heating hot water!
On another note, I think it’s highly debatable whether and electric instant hot water system with no storage capacity is sensible in the near and longer term. Hot water is probably the simplest and most efficient energy storage system available and any discouragement from increasing storage is likely a failed path to higher efficiency.
Seems like it’s a safe bet to pull this down and adjust our blog slightly to reflect this.
I think $100 works out to be a safer claim ($2500 p/year) compared to a traditional water heater.
Thank you @pswired for pointing this out, and @ixu for the math .
Some context: typically for device deep-dives like this, we’re looking for “different” technology that was pushing higher efficiency that a majority of appliances on the market. 100% agree that it might not be a scaleable near/long-term solution - this is something we’ll consider more moving forward.
Of course it’s the little engineer in me, but dollar saving claims mean less to me than raw kWhr metrics.
Dollars conversion is also dependent upon cents/kWhr being paid … and then, perhaps more crucially, as the world moves toward solar the “cost” is one of “is it more efficient to try and dump the energy locally, into hot water or an EV for example, rather than sending it to the grid”.
For that reason, shifting the mindset of consumers away from co$t and more towards coWst (maybe I’ll TM that one!) seems wise. Mindshift = loadshift?
e.g. More simple math on my system … 2 people, small apartment, 40 gallon hot water tank, 0.95EF … averaging 2,146 kWh/year.
I pay about 22 cents/kWh ==> $472 for hot water.
4% of that = about $19/yr.
If I was paying 12 cents/kWh, that 4% would amount to $10/yr.
BUT if I consider the 4% as watts, that’s 86 kWhrs … that’s about what my washer/dryer coWsts per year!
Thanks for taking a closer look here. Unfortunately, this looks like something that is indeed new technology, but the practical benefits to the consumer and the grid as a whole just aren’t there. The energy performance is essentially identical to current on-demand tankless electric water heaters, which do eliminate standby losses, but at the expense of huge instantaneous demand, which makes grid management, especially when combined with the addition of renewables, even more difficult.
This has been removed and altered in our original Water Heaters blog post about 9 months ago. We share social content that is a condensed format of blog posts, so that’s how this was brought up again.