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Will my PV be adequate

  • 22-02-2023 8:54pm
    Registered Users Posts: 21


    My home is approx 2500sq ft Im using OFCH for underfloor and a fair qty of electricity (between 250-300 per month) Im looking at the below package. Im planning a 11.6kw heat pump. My question is: will the PV be enough to run the heat pump and the rest of my energy needs. I can upgrade the panels and inverter to futureproof etc.

    Recom 390W HJT *N-Type Bifacial 30yr warr. to 91.25% Prod. x 16 

    Solis 5kW Hybrid Battery Inverter x 1 

    Weco 5.3KwHr Wall mounted battery with wifi/bluetooth x 1 

Best Answers

  • Registered Users Posts: 2,476 ✭✭✭bullit_dodger

    My home is approx 2500sq ft Im using OFCH for underfloor and a fair qty of electricity (between 250-300 per month) 

    That's actually lower then the Irish average, which is 4500Khw/year. You sure on your numbers there?

    The reality though is that there are two answers to your question. No, your solar installation won't be enough to run your heat pump etc. BUT it will chip in a lot on your household amounts you have to buy. The problem with solar and heat pumps is that solar generates the best electricity when it's sunny (makes sense doh!) ... but of course when do you want to use your heat pump most? Yeah, when it's cloudy, cold and dark in winter. In truth the solar installation would struggle to cover a heat pump as a result, but it's still generally worthwhile investment. It will pay for itself in 8-10 years (unless you pay over the odds) and it will give you a certain stability with respect to energy prices. When they rise like the Ukrainian issue, people with solar felt the pain less as we typically import less than your average household

    If you haven't already, zip over to the quotes thread and familiarize yourself with the state of the market.

    Domestic Solar PV Quotes 2022 - No PM requests - See Mod note post #1 - Page 149 — - Now Ye're Talkin'

  • Moderators, Home & Garden Moderators Posts: 5,905 Mod ✭✭✭✭graememk

    Ill say it now, No, you won't be able to run your heat pump in winter from solar.

    It will likely run a majority of it from march- April onwards.

    This website will give a monthly estimate, put in the kw solar panels, location, direction and slope, everything else as default and it will give you a good indication of how much you'll generate per month.

    As for how much power the heat pump will need. You could estimate that.

    Do you know how much oil you use?

    How new is your oil boiler?

    There's 10kw of heat energy in a liter of oil

    And depending on the boiler it can be 60-95% efficient let's assume 80.

    For every litre of oil your house used 8kwh of heat.

    A heat pump with ufh, should get a good COP say 4. (3 if your feeling pessimistic)

    Divide the amount of kwh you got from oil by 4 (or 3) and that will give you the electric demand of the heatpump


  • Registered Users Posts: 21 paddy00

    Thanks bullit dodger

    Yep the electricity amt is correct - we are pretty light electricity users so I am abit concerned with that fig. The house is well insulated though. Would the batteries store enough to power the HP. I accept the dark miserable Irish winter will mean Im drawing on the grid. What if I had two batteries.