Electric Consumption of Water Heater With Heat Pump

[frankge]

In Florida, my heat pump WH keeps me below my consumption limits. Its also cools my garage so I can "add" the cost savings of buying and running a minisplit. My garage is considered another room in my house. What's even better is I found an 80 gallon AO Smith for $150.00 and its been running for 4 years! If it went I'd get another. During our "Winter" I'll run it in resistance only mode if it gets cold in the garage.

BTW - according to my Sense monitor its using 816 watts right now.

[Rade]

We migrated from an oil-burning hot water tank to a heat-pump version. I keep the tank in heat pump mode; the settings are "Electric" (pulling 100% from the grid to heat water), "Hybrid" (combination heat-pump and electric) and Heat-pump (100% through heat-pump), oh, and vacation mode that keeps the temp above 70 degrees if we are away from the house for x-number of days.

I have not seen any increase in electric consumption between the oil-burning usage (used to power the burner and the circulating pump) and the 100% heat-pump mode. Two adults, 2 showers a day, assorted other hot-water usages. When the tank HAD been depleted (the occasion when I decide to soak in a hot tub); recovering was quick.

[Liam]

Been running a heat pump water heater for a while. What surprised me is how much the actual consumption depends on when you use the hot water. Shifting showers and dishes to the afternoon when the solar is pumping really cuts down on grid pull.
Added a high voltage battery to mine and it’s helped a lot with running everything off solar. This one’s worked well for me:
GRHV-rack-mounted-19-inch-lithium-battery-bank.png

Has anyone else tried timing their hot water use with solar production?

[bcroe]

For 2 houses and 5 decades I have had countless water heater failures,
first leaks, then 3 high efficiency gas units had a high failure rate. The
repair parts for the high efficiency units seem to increasingly become
quite expensive, I hate to think of the cost if I could not do the repair myself.

I very much wish to avoid finding myself in an unexpected crises situation
with no hot water. I already solved that problem with HVAC by decentralizing
to a number of independent mini split heat pumps, with enough extra capacity
to cover a failure thru a winter. After much consideration, I decided to solve
the problem with a life time tank simple electric water heater. These do have
2 heating elements, so I could bypass one until a failure was replaced. I
installed convenient shut off valves to cut off the water while an element is
being replaced, of course a spare is on the shelf.

Energy wise, operational efficiency here has greatly improved since solar was
first installed in 2013. The now excess energy has been partly used by some
luxuries such as running my old central blower 10 minutes of every 30, so my
electrostatic air filter can keep the air free of dust, as well as circulation air in
general. That has worked so well, I am sorry it was not happening most of my
life. When a beam of light slips past a shade, it cannot be seen till you put
your hand in it, as there are no dust particles to reveal it.

Still I estimate my energy surplus is large enough to run a simple electric resistance
water heater, at no cost to me. I would not turn down an opportunity to connect
an external water heating heat pump, but have not been able to get one. For the
future I can imagine a more direct connection between the solar and the heater,
possibly using it as a battery to collect energy now lost to clipping, or just to run
off panels not driving the grid. Have 7 years to think about that for when my Net
Metering contract runs out. Bruce Roe Before.jpg

[Liam]

Sounds good. Simple electric tank with your solar surplus is a smart fix. Should last and stay cheap. Nice setup

[J.P.M.]

Sounds good. Simple electric tank with your solar surplus is a smart fix. Should last and stay cheap. Nice setup

Same as mine since 2005. Annual solar fraction for pumped solar water heating is ~ 0.95. Zip 92026.
Electric resistance used for the other 5%.
PV since 2013 supplies the rest of the electric house load.
Both systems trouble free so far

Much cheaper, much simpler and therefore more reliable that heat pump heater heating which is too complex - like killing flies with artillery, way too expensive and WAY too hype ridden.
Around here, known tech. elec. resistance tanks cost ~ $1,000 - $1,200 at big box and a lic. electrician to wire it costs ~ $1k.
Heat pump cost + setup something like $9-12K depending.
The headaches and downtime on the heat pump are free.
Pay your money. Take your choice.

[Rade]

We have a State hybrid heat-pump hot water tank that I keep in heat-pump mode. The power it consumes is nominal, and I do try and run the dishwasher during late morning when our solar is doing some decent generation.

Our biggest power consumption comes from charging EV's on the 50amp L2 chargers at home. We have two EV's. I am retired and do not need to keep my truck tanked up at all times. My husband needs his car as a daily driver for work, so he plugs in when he gets home in the afternoon. I was using the charging timer on the truck to only allow the truck to charge during peak sun hours, but have found that it is just as economical to go to the DC Fast charge center once a week. Here in RI, there is no discount for kW (no TOU). And the price per kW is the same if I charge at home as it is if I charge elsewhere. The benefit is that NOT using solar during the day puts more into the Net Credit bank now for use in Winter. Husband does not have the luxury of time to charge elsewhere, so he's getting his car charged off the solar until the sun sets below the power production (usually around 6:30 this time of year).