time scheduling a “dumb” electric water heater
I just got an EV, and switched to an ultra low overnight rate plan. The cost of getting this ultralow overnight rate ($0.068CAD/kWh, delivery, taxes, regulatory charges included) is an exorbitantly high peak rate of $0.324 from 4-9PM. Aside from the EV, my biggest energy users are space heating/cooling and water heating. I can already time schedule my heating/cooling, and I’d like to do the same with the water heater. Unfortunately, the heater itself has no programming capability. Is there a solution that’s worth the time and effort? My current best idea is to install a relay to disconnect water heater, which I’d plug into a GreenDot timer I already have. I know there are smart breakers, but I’m assuming those aren’t meant for large numbers of on/off cycles and I’m also guessing they aren’t cheap.
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What is the amperage/voltage on the water heater?
240V, 19A
I would use something like this
https://dewenwils.com/products/dewenwils-wireless-wi-fi-pool-pump-timer-box-for-pool-water-heater-compatible-with-smart-phone-alexa-google-assistant-s2howt01a1?currency=USD&variant=45018518847785&utm_source=google&utm_medium=cpc&utm_campaign=Google%20Shopping&stkn=b4f6b6f62bfd&utm_source=google&utm_medium=pm&gad_source=1&gclid=EAIaIQobChMI-7rjsd6mhgMVOCWtBh0KOw8DEAQYCSABEgJykvD_BwE
The ROI on that might be too long, but it did send me down a path to find a non-wifi version for under $20, so thanks.
Can you share the one you found?
https://www.amazon.ca/gp/aw/d/B084ZPXGN8?ref=ppx_pt2_mob_b_prod_image
I would strongly recommend against wiring an unlisted device - or even plugging one in. In Canada you want to look for an accepted certification like CSA or CUL. If it starts a fire is your insurance still valid? (I don't trust anything electrical from an unknown off-shore company even if they claim the device is listed; it's not worth the risk.)
I think this could also work. I use one in my vacation home to turn the tank off when I’m away on a schedule.
https://aquanta.io/wifi-water-heater-controller-electric-heater/
Looks like it would work well, but not sure it's worth the price ($150) when I can get a relay timer for $15. It also appears to be one of those things that will cease functioning if the company goes under, which I try to avoid.
If that's the case, Intermatic has made mechanical water heater timers since forever. No software at all!
https://www.amazon.com/Intermatic-WH40-Timer-7-75-inches/dp/B00004W4XI/ref=asc_df_B00004W4XI/?tag=hyprod-20&linkCode=df0&hvadid=693420779708&hvpos=&hvnetw=g&hvrand=18341521774872625561&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=1013585&hvtargid=pla-343152853914&psc=1&mcid=255bf428fabe34d6a74fb6446263603e&gad_source=1
Another vote in favor of a tried-and-true mechanical timer from Intermatic. Simple, foolproof, dependable.
I plan on using a contactor (high current relay) and something like the Shelly Plus to control the contactor. This will stay on schedule better than a mechanical timer, and I bet it's cheaper too.