New Heat Pump Hot Water Heater = All Electric Home

[redpoint5]

Originally Posted by Piotrsko

SO the issue becomes, does restoring power to the new WH after bringing it back from off for 8-10 hours cost more than maintaining 120f? I would think not, that would be the useage scenerio for the compressor heater

It never costs more to heat or cool a thing as needed than to maintain a continuous temperature, at least from an energy consumption standpoint. That's why turning the thermostat off when everyone leaves the house saves energy compared to maintaining a continuous temperature.

The law of entropy causes heat to disburse, and the greater the temperature differential, the more rapidly that occurs. Allowing temperatures to drift towards equilibrium when not needed means less continuous heat transfer.

[JSH]

My water heater has both the heat pump and 2 regular electric elements. The water heater has 4 modes that blend the use of those heat sources. Anything from only using the heat pump to only using the resistant elements. Between those extremes are 2 modes that blend the use with the trade-off that the more eco mode has slower recovery time.

It would be possible to use more electricity with a schedule vs steady 125F hold depending on how the schedule was designed and the usage mode for the water heater. If I set the water heater for fast recovery and then let the water temp drop to something like 110 degrees only to be heated each morning with the electric elements I'm sure that would use a lot more electricity than holding the water at a steady 125F all day using the heat pump. (Which is roughly 3x more efficient than the element heaters.

[cRiPpLe_rOoStEr]

Originally Posted by JSH

I guess it depends on what you mean by not succeeding

In the end it didn't save much on the electricity bills when I last saw anything about that.

[JSH]

Originally Posted by cRiPpLe_rOoStEr

In the end it didn't save much on the electricity bills when I last saw anything about that.

No it wouldn't save much money because refrigerators don't use much electricity - especially small to medium size ones that are used in most of the world. The 74L fridge I bought for the ambulance has used 1.14 kWh in 4 days of testing. Even if someone could recover all of that energy as waste heat it would be pennies a week.

Recovering waste heat from A/C doesn't make much sense on a small scale. It could have reasonable savings at a commercial scale. For example some server farms are heating hot water with some of their waste heat from running their huge A/C units. They are also experimenting with using that waste heat to provide heating for other buildings.

[cRiPpLe_rOoStEr]

Originally Posted by JSH

No it wouldn't save much money because refrigerators don't use much electricity

The claims I found were that using the serpentines of the fridge to heat water rendered it more difficult for the heat to dissipate, increasing the load on the compressor in order to mantain a low temperature inside. So, compared to the electrically-heated shower heads more usual in my country, maybe the only economy would be not having to replace a heating element inside the shower head again

[Piotrsko]

You can still buy a fridge with the serpentine coils?

[redpoint5]

I assume you've cancelled gas service to save on the monthly meter fee?

I go the opposite direction and try to gasify everything I can. Ran a line out to the back deck so my BBQ is on natural gas. Used a Y adaptor to plumb in a patio heater. Bought a used natural gas dryer using OfferUp app. I've got a natural gas dryer in the Vancouver house, and in my current house now, both bought used for $50, and both running perfectly years later. They dry much faster than an electric dryer.

The range is natural gas, as well as furnace and 2 fireplaces.

Only thing not natural gas is the oven, which is built in with the microwave above.

I need to complete the carburetor conversion on one of the gensets to utilize NG so that next outage I have unlimited cheap electricity, and don't have to be concerned with stale gas gumming up the carb.

[Piotrsko]

You have natural gas available. The trench alone for me would be 15 large plus whatever it took to plumb and vent the house and buy all new appliances

[redpoint5]

Originally Posted by Piotrsko

You have natural gas available. The trench alone for me would be 15 large plus whatever it took to plumb and vent the house and buy all new appliances

I don't recall exact prices, but my parents got electricity, gas, and cable run about 170ft to their new (used) mobile home for extremely cheap. I want to say one company charged $1, the other was free, and the other might have been $100.

Trenching is easy if there's not too many boulders.

... I inquired about running gas to a particular house once, and the gas company would have to extend their line along the road and they quoted me $50k to do that. Then everyone else would get cheap access to the line I would have paid to run.

[JSH]

Originally Posted by redpoint5

I assume you've cancelled gas service to save on the monthly meter fee?

I go the opposite direction and try to gasify everything I can...

Yes, I called and cancelled service and had them come out and physically turn off the gas to my house. (They didn't want to do that initially.) We were paying more for the connection charge than for gas.

For me it was all about dollars and cents.

When we bought the house it had a decades old gas furnace. Inefficient and likely to fail at the most inconvenient time and force me into a rushed and expensive replacement. I originally planned to replace it with another gas furnace but even a base inefficient model was several thousand more than the ductless heat pump that we ended up installing. A new furnace + central A/C would have been about $7K more than the heat pump. So it was thousands cheaper up front to go with the heat pump.

Then there are the operating costs which are much less heating with electricity. With the gas furnace my December bill was $209 ($135 for gas +$74 for electricity). After we switched to a heat pump that dropped to $131 ($113 for electricity + $18 for gas) We also keep our house warmer because of the savings. With the gas furnace the heat was set to 68F. Now we keep the house at 72F when we are home and awake. (The heat pump is on a schedule)