I'm actually switching from 2 50 gallon propane water heaters to one single 80 gallon electric.
My propane bill to run these 2 water heaters plus have a burner or two on for a total of probably one hour a week is almost $100/month. Gas is $3.10/gallon + taxes here in Jacksonville, FL.
We have 4 full baths with only occasional in-law guests. Baby is on the way. I think we need the 80 mostly because our planned master bath remodel is probably going to have 6 body sprays and probably a rain shower head and a hand shower. So occasionally, we would like the ability to drain that 80 gallon in 10 minutes.
If i'm not mistaken, the stand-by losses on electrics are a lot less than the propane units in general.
The "high efficiency" A.O. Smith 80 gallon electric i'm looking at has a published 4721 KWH yearly use. At .13/KWH out the door cost, that breaks down to about $51/month, which means I save $40 or more per month, since i'm thinking we actually use less than that published amount. What we use now is about 2 showers per day and run the dishes every 3 or 4 days. Total cost after 10 years = $6120 + $620 initial cost = $6740
I looked at the heat pump water heaters and although that looks to cost me about $21/month in electricity, the upfront cost difference of about $1580 is huge (these cost about $2200 out the door). It will take 51 months to make up that upfront cost difference when figuring saving $31 more per month using the HPWH. However, long term, I do realize it start to really pay off after 10 years. Total cost after 10 years = $2520 + $2200 initial cost = $4720.
After 10 years, I save $2020 if I go with the HPWH.
I think its more likely that the HPWH will break down within 10 years rather than the conventional electric unit blowing any savings out the window, but that's just my opinion.
Am I missing something here? Input is welcomed.
Now on to the electrical problem at hand.
I have a picture of a 90 amp double pole from the main panel which feeds the sub-panel. In the sub panel is what I assume is 90 amps, since each single pole has two little small 15's on each?
So I think this means that I can't put a double pole 30amp in there?
Is my only option now to double up on another breaker replacing the existing breaker with something bigger?