I have been toying with the idea of supplementing my energy usage with solar panels. I have been studying costs and payback time and what I might need. I have been reading this forum for the last year to get ideas. Folks always recommend you do an energy audit to see how much energy you consume. I decided to buy the Emporia VUE energy monitor and the results after a week or so have really blown my mind. I have a heat pump system and all-electric house. Got up the other morning and put the thermostat up to 70 degrees, started the microwave for heating some water for coffee, and my wife was in the bathroom using some hot water to wash her face. Holy cow, my energy usage shot up to 19,109 watts!! After seeing that I have had to reevaluate my ideas. If you are in the beginning stages of designing a solar system, I highly suggest buying one of these systems to actually see how much energy you actually use. It might just be an eye-opener.
Surprised by energy usage
- Thread starter Loadtoad
- Start date
SignatureSolarJames
Try Solar, the Grid will always take you back
do you have both heat strips on or just one heat strip in the breaker panel running?
timselectric
If I can do it, you can do it.
- Joined
- Feb 5, 2022
- Messages
- 18,628
Research is cheap, and the wrong equipment is expensive.
EastTexCowboy
Solar Wizard
Seems to me one of the key words in your post is "supplementing". You can absolutely supplement on just about any level, depending on your goals and budget. That said, you made a solid decision to do the monitoring. Good job on that and good luck!
You're doing the right thing! Emporia VUEs are extremely cheap for what they are and what they provide, I can't recommend them enough for everyone out there. We're fortunate in Texas that we're provided with the ability to download 12 months of usage data with 15 minute granularity for free at any given time which can help with initial assessment.
19kW of peak usage is probably not unheard of but don't let it scare you away from getting a system that may not allow you to run your heater, dryer, oven, EV charger all at the same time but can easily cover most of your use case.
Realistically the 80-20 rule applies here just like everywhere else in life. You can get 80%of the coverage for 20%of the cost, or the last 20% can cost 4x as much as the first 80%. Unless you have genuine need to be 100% covered 100% of the time you can get a system that covers most days and most consumption.
Without knowing much about your situation, your PV install will largely be limited by your budget, large grid-tied systems with back-up tend to be on the expensive side but are probably providing the best ROI and the most benefit.
19kW of peak usage is probably not unheard of but don't let it scare you away from getting a system that may not allow you to run your heater, dryer, oven, EV charger all at the same time but can easily cover most of your use case.
Realistically the 80-20 rule applies here just like everywhere else in life. You can get 80%of the coverage for 20%of the cost, or the last 20% can cost 4x as much as the first 80%. Unless you have genuine need to be 100% covered 100% of the time you can get a system that covers most days and most consumption.
Without knowing much about your situation, your PV install will largely be limited by your budget, large grid-tied systems with back-up tend to be on the expensive side but are probably providing the best ROI and the most benefit.
MurphyGuy
It just needs a bigger hammer
- Joined
- May 20, 2020
- Messages
- 4,129
Your house pulling 20,000 watts doesn't mean anything for a grid-tied solar system. Far more important is how many Watt-hours you use overall per day.
Give it a few weeks and see how much energy (measured in kWh) you average per day, then design a solar system around that.
Give it a few weeks and see how much energy (measured in kWh) you average per day, then design a solar system around that.
Bud Martin
Solar Wizard
- Joined
- Aug 27, 2020
- Messages
- 4,844
BTW, 'my energy usage shot up to 19,109 watts!!'
What was the reading before that? that is just a reading at that moment, but if you use it for 1 Hour then you will be paying for 19.109kWh of consumption.
What does your utility bill show for the power consumption per day?
What do they charge you per kWh?
What was the reading before that? that is just a reading at that moment, but if you use it for 1 Hour then you will be paying for 19.109kWh of consumption.
What does your utility bill show for the power consumption per day?
What do they charge you per kWh?
Last edited:
kWh/day may not even tell the full story either.
At the very least you'd need to know your daytime vs. nighttime consumption and whether any of that consumption can be shifted around with relative ease (for example can you do your laundry mid-day vs doing it at night, can you charge an EV during the day vs. doing it at night etc.)
Additionally, consumption can and does vary greatly by season, so you have to look at that too.
daytime vs. night time usage will give you an idea on what you can cover with solar and what you have to either cover with storage or with a net metering agreement. Since net metering agreements are dwindling in supply, you may not want a system that generates excess solar during the day unless you're willing to capture it in storage for self consumption. Batteries are expensive and the ROI may not be worth it from a strictly energy sense.
fmeili1
Solar Enthusiast
Just to mention... in case you already use a smart home system with Z-Wave radio protocol (OpenHAB, Home Assistant, etc.), the "Aeotec ZW095 Home Energy Meter Gen5" does the same for an similar price (no WiFi, no special App).
As others stated, it's very important to know the power and energy usage in the pre-planning phase of a solar project. In case of going off-grid (or non-grid-interactive with grid just as a backup) it's even more important. After doing my measurements, I realized that I should go with more inverters in parallel for my non-grid-interactive system to have enough reserves. Also it's nice to know that in "standard" usage the inverters are not fully utilized - I think, they'll live longer because of that.
As others stated, it's very important to know the power and energy usage in the pre-planning phase of a solar project. In case of going off-grid (or non-grid-interactive with grid just as a backup) it's even more important. After doing my measurements, I realized that I should go with more inverters in parallel for my non-grid-interactive system to have enough reserves. Also it's nice to know that in "standard" usage the inverters are not fully utilized - I think, they'll live longer because of that.
You got me excited only to be disappointed. This device only measures two phases and their power which is a far cry from the Emporia VUE's 16 channel capability.
There is information out there where people did break the Emporia and loaded custom ROM onto it to make it home assistant compatible if that is the route you want to take.
timselectric
If I can do it, you can do it.
- Joined
- Feb 5, 2022
- Messages
- 18,628
1. Size your inverter for maximum expected load, at any given time.
2. Size your battery for how long you want to run, without sunshine.
3. Size your solar to cover your daily loads, and replenish your battery.
2. Size your battery for how long you want to run, without sunshine.
3. Size your solar to cover your daily loads, and replenish your battery.
fmeili1
Solar Enthusiast
They have this model with 1 phase, 2 phase (split phase) and 3 phase, depending of the local market and situation. Here in the US, I'm using the split-phase model to measure my 200A house sub panel. It runs now since 9 month with my OpenHAB system without any issue. In case you need more than 3 phases (channels) you need to go for sure with a different product like Emporia VUE. But for a typical whole house measurement for 1 to 3 phases that might be ok... an in my case the Z-Wave integration into my existing OpenHAB made the difference.
I like to know where my power is being used within the house, this is something that is not easy to measure without a clamp on every breaker. This way I can see what my refrigerator is using and what went into my EV or where are my dead loads that I just can't get rid of. I actually have five Emporia VUE units to measure every breaker in my house.
fmeili1
Solar Enthusiast
Ok, now I understand - you want to be able to measure ALL breakers separately! That's a different story - and it's really nice to be able to monitor all these consumers separately all the time! For my initial solar calculation I've measured just the delta of the whole house consumption while switching them a couple of times on and off one by one to get a rough idea about each consumers separate consumption. I've just done this for curiosity but it was not really required to specify my off-grid solar for the whole house.
fmeili1
Solar Enthusiast
That's the right way to do and I've designed it like that.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
Another misconception is that is what you are getting charged for also.
If you used 19kw for an hour then yes but if only used 19kw for 5 minutes then your charge would be a lot less.
It does give you an idea of peak draw though.
Yeah, if you've got unlimited funds...
For those of us off-grid with no rich uncles, there are these two rules -
1. Size your LIFE around the solar system you can afford. If you can't power it, you'll need to live without it.
2. Buy really good and proven stuff, and have a drop-in replacement for everything. Home Depot is NOT just around the corner.
robby
Photon Vampire
- Joined
- May 1, 2021
- Messages
- 4,129
If your grid tied and running an AIO unit it makes zero sense to plan your system around the peak power usage.
The system will be very expensive and under utilized most of the day. Plan your system around your average daily consumption and then let the Grid handle the couple of hours per day of really high usage.
Your electric bill will be super low and you won't have to shell out an additional $10K just to handle a $50 per month bill.
The system will be very expensive and under utilized most of the day. Plan your system around your average daily consumption and then let the Grid handle the couple of hours per day of really high usage.
Your electric bill will be super low and you won't have to shell out an additional $10K just to handle a $50 per month bill.
timselectric
If I can do it, you can do it.
- Joined
- Feb 5, 2022
- Messages
- 18,628
I agree, you should probably be considering grid-tied.
Similar threads
