Tesla Announces Powerwall 3 "DC Expansion"

[Jeremy3292]

Why would you say that? You only heat the water you use, instead of the water you use plus keeping it hot 24hrs a day. A quick search on Google for "energy used water heater 50 gal vs. tankless" shows a 30% avg savings with a tankless.

Sorry my bad. I was thinking UEF ratings were the same, but yes since you’re heating on demand only it uses less energy. But a HPWH uses far less energy (and doesn’t require using a lot of your panel box), which is what I’m going for.

 

[Docfxit]

I don't know what the temperature is like by you.
At what temperature is a heat pump water heater useless?
between 25 and 40 degrees Fahrenheit
Heat pumps do not operate as efficiently when temperatures drop to between 25 and 40 degrees Fahrenheit for most systems. A heat pump works best when the temperature is above 40. Once outdoor temperatures drop to 40 degrees, heat pumps start losing efficiency, and they consume more energy to do their jobs.

 

[Jeremy3292]

I don't know what the temperature is like by you.
At what temperature is a heat pump water heater useless?
between 25 and 40 degrees Fahrenheit
Heat pumps do not operate as efficiently when temperatures drop to between 25 and 40 degrees Fahrenheit for most systems. A heat pump works best when the temperature is above 40. Once outdoor temperatures drop to 40 degrees, heat pumps start losing efficiency, and they consume more energy to do their jobs.

Yes, correct. I am in upstate SC and mine will be in my garage where the current one is. So I don't foresee any issues

 

[GregBallantyne]

Yes, correct. I am in upstate SC and mine will be in my garage where the current one is. So I don't foresee any issues

An actual data point - my heat pump water heater has been in use 2 days short of 10 months. It has a decent app that tracks power consumption - During that time, it has used 784.5 kwh. Set on heat pump mode the entire time. Average is easy - about 78.5 kwh/month. No hard data on my previous water heater power useage, but I've read the average is around 350 kwh/month.
It's in my basement, a semi - heated space. In winter, the temp in the basement around the heater can drop down to 48-50 F. At this temp, recovery takes a bit longer. Just 2 of us, not an issue. Appears to be plenty of space to use hybrid mode seasonally to address that if need be, and still realize significant power reduction. I sure noticed the difference in my consumption quickly - it got me over the line between using some grid vs self powering for some of the summer months.

 

[Jeremy3292]

An actual data point - my heat pump water heater has been in use 2 days short of 10 months. It has a decent app that tracks power consumption - During that time, it has used 784.5 kwh. Set on heat pump mode the entire time. Average is easy - about 78.5 kwh/month. No hard data on my previous water heater power useage, but I've read the average is around 350 kwh/month.
It's in my basement, a semi - heated space. In winter, the temp in the basement around the heater can drop down to 48-50 F. At this temp, recovery takes a bit longer. Just 2 of us, not an issue. Appears to be plenty of space to use hybrid mode seasonally to address that if need be, and still realize significant power reduction. I sure noticed the difference in my consumption quickly - it got me over the line between using some grid vs self powering for some of the summer months.

Good information. Home Depot has a 65 gallon Rheem on “spring Black Friday” so I ordered that one and my plumber will install it next Friday. I don’t foresee using more than 100 kWh per month with the HPWH and likely under that like yourself. And since I got a 65 gallon instead of 50 gallon, I imagine I can be on heat pump mode virtually all the time.

I’m hoping this will help me out a lot in the winter and summer months when energy usage is much higher in general.

 

[BGbreeder]

An actual data point - my heat pump water heater has been in use 2 days short of 10 months. It has a decent app that tracks power consumption - During that time, it has used 784.5 kwh. Set on heat pump mode the entire time. Average is easy - about 78.5 kwh/month. No hard data on my previous water heater power useage, but I've read the average is around 350 kwh/month.
It's in my basement, a semi - heated space. In winter, the temp in the basement around the heater can drop down to 48-50 F. At this temp, recovery takes a bit longer. Just 2 of us, not an issue. Appears to be plenty of space to use hybrid mode seasonally to address that if need be, and still realize significant power reduction. I sure noticed the difference in my consumption quickly - it got me over the line between using some grid vs self powering for some of the summer months.

Out of curiosity, how close is that the the yellow energy label on your water heater? (Make/model?)

All the best,

BG

 

[GregBallantyne]

Out of curiosity, how close is that the the yellow energy label on your water heater? (Make/model?)

All the best,

BG

The yellow energy label on it says $103 annual operation cost estimate. My annual cost to date at my grid charge rate of $0.16 kwh would come to $150.72, so I'm not certain of the detailed estimate basis. It has 3 possible operating modes - it can be operated just the same as a water heater without a heat pump, a hybrid mode that prioritizes heat pump operation hut will throw in the elements when required, or heat pump mode only. Mine has been run on heat pump only mode, so a rate of more like $0.11 kwh would be required for that. My 2023 rate was close, at $0.12 kwh. It's an A.O.Smith model HPTS-50 200. Had a model name, but I can't find it at the moment.