I just completed my first energy audit and am trying to figure out the proper system size. Here is a screenshot of the calculations:
I have three primary goals: (1) to offset grid cost (2) to slowly become more self-reliant and (3) to create a backup solar generator in the event of a power outage.
The items that I've chosen in the energy audit above represent the most important items to keep running in the event of a power outage.
What I'm hoping is that someone might be able to help let me know if I've done this correctly. I was quite surprised by the cost as well as the number of years it will take to break even. I fully admit that I may have missed something in all these calculations.
I chose the insolation # of 2.29 because that's the absolute worst for my area (of NE Ohio). If I am going to run the heater in the winter, I need it to work during the worst time for solar. Even so, 32 panels at 440 watts each seems a little excessive to me for just a couple of appliances.
I have a smart thermostat that tracks heater usage. The coldest month last year (February) averaged almost 10 hours per day. I cheated on this number just a bit and bumped it down to 7 hours per day. I figured I could use grid power if absolutely necessary. Otherwise, in a power outage, I can justify keeping it a bit colder in the house.
Power in my town is $0.10 per kWh. I know that's cheap, and that this affects the payback period. Even so...44 years seems incredibly unreasonable. Even if I paid twice that amount it's still 22 years. By that time batteries may need to be replaced anyway, so I don't see any scenario where this is going to be a wise decision from an economic standpoint.
I am still willing to move forward if I can't accomplish my first goal of offsetting grid cost. Even if it doesn't pay for itself, I still accomplish the goal of achieving more self-reliance and having backup power. That's valuable to me.
But I still think this should be cheaper than it's looking like it will be. Did I make an error in my calculations? What variables should I change or sacrifice to get the cost down?
Thanks!
I have three primary goals: (1) to offset grid cost (2) to slowly become more self-reliant and (3) to create a backup solar generator in the event of a power outage.
The items that I've chosen in the energy audit above represent the most important items to keep running in the event of a power outage.
What I'm hoping is that someone might be able to help let me know if I've done this correctly. I was quite surprised by the cost as well as the number of years it will take to break even. I fully admit that I may have missed something in all these calculations.
I chose the insolation # of 2.29 because that's the absolute worst for my area (of NE Ohio). If I am going to run the heater in the winter, I need it to work during the worst time for solar. Even so, 32 panels at 440 watts each seems a little excessive to me for just a couple of appliances.
I have a smart thermostat that tracks heater usage. The coldest month last year (February) averaged almost 10 hours per day. I cheated on this number just a bit and bumped it down to 7 hours per day. I figured I could use grid power if absolutely necessary. Otherwise, in a power outage, I can justify keeping it a bit colder in the house.
Power in my town is $0.10 per kWh. I know that's cheap, and that this affects the payback period. Even so...44 years seems incredibly unreasonable. Even if I paid twice that amount it's still 22 years. By that time batteries may need to be replaced anyway, so I don't see any scenario where this is going to be a wise decision from an economic standpoint.
I am still willing to move forward if I can't accomplish my first goal of offsetting grid cost. Even if it doesn't pay for itself, I still accomplish the goal of achieving more self-reliance and having backup power. That's valuable to me.
But I still think this should be cheaper than it's looking like it will be. Did I make an error in my calculations? What variables should I change or sacrifice to get the cost down?
Thanks!
