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How to work out savings with adding Solar

  • 03-03-2019 11:35am
    #1
    drunkmonkey
    Registered Users Posts: 28,067 ✭✭✭✭


    nevermind.....


Comments

  • #2
    unkel
    Registered Users Posts: 64,681 ✭✭✭✭unkel


    Eh? :)

    Not that easy to make an educated guess of your savings, as you won't get paid for exporting to the grid. And you don't really know how much you have exported (unless you install an export meter). And even if you did know how many kWh from your solar you have self-consumed, the value per kWh depends on your use of the electricity

    i.e.

    -the electricity to power the back load of your house is worth the full day rate of say 18c/kWh (during the day)
    -if you use solar to charge your car, you could have done that at the night rate of say 8c/kWh, so it is only worth that
    -if you use solar to heat your water, you could have done that with gas which costs maybe 5c/kWh and you needed to invest in a diverter system, which cost money, so this is really only worth maybe 2c/kWh

    I guess a good estimate would be your total annual bill compared before and after the install. Making sure to compare kWh used, not the standing charges or the price of a kWh

    Almost all figures I have ever seen for savings people reckon they make seem way too optimistic to me. Maybe people want to justify their investment in solar PV to themselves, I don't know.


  • #3
    drunkmonkey
    Registered Users Posts: 28,067 ✭✭✭✭drunkmonkey


    So reckon I'm using about 25kWh a day going by my electricity bill. Question is what type or battery panel set up would you need to power the house per day.
    A 25kWH battery? Cost doesn't really make sense if looking at that many panels and battery. Am I missing something?


  • #4
    unkel
    Registered Users Posts: 64,681 ✭✭✭✭unkel


    The average Irish household uses 3.5MWh per year or a bit under 10kWh a day. Are you cryptomining or do you use electric showers or something that would explain your extremely high electricity consumption? :)


  • #5
    Alf Veedersane
    Registered Users Posts: 24,549 ✭✭✭✭Alf Veedersane


    unkel wrote: »
    The average Irish household uses 3.5MWh per year or a bit under 10kWh a day. Are you cryptomining or do you use electric showers or something that would explain your extremely high electricity consumption? :)

    Might be a house with storage heating?


  • #6
    drunkmonkey
    Registered Users Posts: 28,067 ✭✭✭✭drunkmonkey


    The heating is oil fired, there's 2 electric showers. All lights are led, only 1 telly on at a time. Besides that it's just the usual cooker, fridge, washer and dryer.
    It does seem like a lot of electricity, is there an easy way to see what those showers are consuming the Mrs has a habit of not pulling the strings for them when finished so the little light on the shower stays on. nobody else uses the electric showers.


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  • #7
    antoinolachtnai
    Registered Users Posts: 9,772 ✭✭✭antoinolachtnai


    This usage puts you in the ‘top quartile’, ie you use more electricity than at least three quarters of (non storage heating) electricity users.

    You need to monitor the meter for a few weeks and see what is going on.

    Using or not using the isolator switch will make no difference to electricity consumption.


  • #8
    unkel
    Registered Users Posts: 64,681 ✭✭✭✭unkel


    drunkmonkey wrote: »
    there's 2 electric showers

    Using each for 30 minutes per day would double your electricity consumption from 3.5MWh to 7MWh per year :D

    3.5MWh for 2 showers, that's far, far more than the electricity I consume to drive my family car (EV) around for the year :)


  • #9
    drunkmonkey
    Registered Users Posts: 28,067 ✭✭✭✭drunkmonkey


    Only of them is used for maybe 10 minutes a day. We've another shower powered by a pump maybe 10 minutes a day as well.

    Looking at the power consumption of the washer and dryer and the TV this is where I'm getting confused...

    The TV specs say 428 kWh/yr, rated power consumption 436W
    120 kWh/a is the washer
    280.4kWh is the dryer.

    Then it goes on to say about the dryer
    PERFORMANCES
    Energy class
    A++
    Energy consumption kWh cotton cupboard dry 50% moisture (1400rpm spinning)
    2.13

    Washer and dryer could be on for 5hrs between them a day and maybe the TV 4hrs.


  • #10
    KCross
    Registered Users Posts: 12,066 ✭✭✭✭KCross


    Forget the specs of the appliances. They are meaningless as they dont account for the program/settings that you use.

    Get yourself an energy monitor that goes into a 3 pin socket. Connect it to each appliance in turn and run your normal program and get the kWh's used at the end for that appliance. Then do your multipliers.


    Something like this
    https://www.ebay.ie/itm/LCD-13-amp-Energy-Monitor-Power-Meter-Plug-in-KWH-Watt-Electricity-Meter-New/331683398801


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