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thermodynamic panel

  • 19-10-2021 12:00pm
    Registered Users Posts: 2,727 ✭✭✭

    Well now that ive the PV installed - the ads i get are chnaging to the next big thing. Thermo panels! Free HOT Water! Works with your PV system! Works 24/7 365!

    Is this a thing? Is it a resonable cost? Is anyone doing it ? Is there a grant? :)

    I didnt install the Eddi - i didnt see any value in changing my system so im guessing this is not going to be something i want either - but thought id ask here...


  • Registered Users Posts: 110 ✭✭DennisZ

    we have both (got thermal panel with the house).

    • the water is not hot - about 55C max,
    • it is not free either - there is (bi)annual service 180 euros.

  • Registered Users Posts: 10,357 ✭✭✭✭the_amazing_raisin

    Sure the thermal panels were a thing before solar PV became popular, they've been installed on most new houses since 2012

    My brother has them on his house, he gets free hot water for about half the year

    Not sure how they compare to a diverter like an Eddi. Thermal panels probably collect more heat, but you could be better off just installing more PV panels since you already have them plus a diverter

    I think the thermal panels have gone out of fashion slightly since heat pumps became popular. The house I'm in was built in 2017 and got it's A3 rating on the heat pump alone, so no panels were needed

    Personally I'm going to cover the roof with PV and then see if I can get a newer heat pump that'll act as a diverter

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost

  • Registered Users Posts: 1,760 ✭✭✭dudley72

    I rang about this the other day, guy said the grant was a waste of money. For a large house it was close to 5k he said which I think was based on 6 people I said. For that money I will be just adding more panel to PV

  • Registered Users Posts: 2,413 ✭✭✭embraer170

    I have them on my 2011 house.

    Maybe I have been unlucky but they have been a maintenance pain. Had a part break and leak glycol all over the utility room once. The refilling of the system (meant to be done every 2 years or so) is also not a DIY job, and depending on where you are might cost a few hundred euros.

    When I get a proper solar system (+ air to water heatpump to replace my gas boiler), I would probably get rid of the thermal panels .

  • Registered Users Posts: 3,463 ✭✭✭Shoog

    Solar PV with diverter will undoubtedly be a better investment. Anything with modifications to plumbing involved is hideously expensive. PV will do some heating of water even on deeply overcast days when any solar hot water system wont even switch on.

    Solar thermal in many parts of Ireland is simply a waste of time so you would be well advised to get a sun days survey before splashing any cash. Our conventional solar thermal panels have been a huge disappointment.

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  • Registered Users Posts: 10,357 ✭✭✭✭the_amazing_raisin

    When you think about it, you're basically running a load of water pipes up to the area of your house which gets the most extreme weather and is most difficult to access

    Also they can only be serviced by a few companies

    I can see why they became unpopular

    One thing I'd recommend with the heat pumps is to see how many registered service guys there are with whatever brand you choose.

    My one only seems to have 2 "official" companies supporting them. The one I've dealt with were grand but you'd wonder what happens when you need an urgent repair and they're busy

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost

  • Registered Users Posts: 1,675 ✭✭✭Deagol

    Some cowboy tried to get me to buy these when I was trying to get quotes for PV. After running the numbers I quickly realised they are snake oil - the amount of power required to run them plus servicing costs / likelihood of failures etc vs what you get out makes them a terrible investment. You'll never make your money back on them.

  • Registered Users Posts: 10,357 ✭✭✭✭the_amazing_raisin

    If you want a good laugh look up the Hone website. Talk about ludicrous marketing, you know when nanotechnology gets mentioned you should run away

    They mentioned some house in Galway they got to NZEB standard using their panels. Then they casually threw out that there's 30 PV panels on the garage as well

    I wonder where most of that energy is coming from...

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost

  • Registered Users Posts: 1,675 ✭✭✭Deagol

    Sites like that make my blood boil - pure and utter garbage with not a single shred of actual honest information.

    My god, even the most basic of maths is garbage; if the average joe could be bothered to look at it. The case study of the house in Dublin where they mention "a heat pump with annual electricity bills of €1,200 plus"

    Yet just a paragraph below that they say the amount of electricity a year would be 4000kwh's a year - or @current 20c kwh - that would equal €800 NOT €1200.

    Oh, and my favourite - using a conversion rate for oil to power of "just over 10 kWhrs of heat in a litre of heating oil". Totally either ignoring or not understanding efficiency of use factors such as boiler efficiency and other losses.

  • Registered Users Posts: 450 ✭✭The devils

    Install one of these about 9 years..maintenance free.

    Have to say it's been great for us.

    Just wondering will an eddi work with it ?

    My PV is due to be installed next month hopefully

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  • Moderators, Home & Garden Moderators Posts: 5,469 Mod ✭✭✭✭graememk

    An eddi is just an immersion controller. So if you have an immersion, it will work

  • Registered Users Posts: 450 ✭✭The devils

    Its does tks..I'm just wondering will it be better for me to ;

    1. Leave it auto - which is immersion and panel

    2. Immersion only

    3. Panel only (which is eco)

    Cheers n

  • Moderators, Home & Garden Moderators Posts: 5,469 Mod ✭✭✭✭graememk

    In the winter it will need to be on auto as you'll have little excess.

    In the summer, I'd be panel only, and spring and autumn there will be a point where you'll need to switch back to auto.

  • Registered Users Posts: 2,331 ✭✭✭bullit_dodger

    As a side question (just incase you hadn't thought about it), since you already have a source of hot water.....would you not be better of forgoing the EDDI and getting a bigger battery in your forthcoming PV installation with that money?

  • Registered Users Posts: 450 ✭✭The devils


    TBH it's always in auto and I've never seen the indicator (immersion on). Maybe this only comes on if there is an issue with panel?

    Thanks for all those suggestions 👍will do

  • Registered Users Posts: 450 ✭✭The devils

    Never thought of that..the battery with the install will be 2 x puredrive 5kw..say take the 450 for eddi off price and buy another 5 kw battery in the coming months. Would that not be a bit much backup ?

    Now I'm not sure 🙈 thanks

  • Registered Users Posts: 2,331 ✭✭✭bullit_dodger

    Ultimately the perfect size battery for your house will depend on your consumption. -Any- battery is a good start, but typically the bigger batteries have a slightly better payback the capacity doesn't (usually) increase linearly with price, unless your going DIY in which case your buying cells.

    The main constraint of course is that you need to be able to "cycle" the battery storage for it to be worthwhile in generating your payback. As in there's no point in having 20Kwhr of storage if your only using 10Kwhr a day. The extra storage you have bought is effectively unused. (there are edge cases here, but I won't go into them)

    Sounds though from your original mail that the thermopanels are doing well for you. They are generally about 50% efficient in capturing the sun's energy while PV panels are approx 20%, so your thermo panel will probably do a better job in heating water than the EDDI will ever do for you.

    Assuming you have enough hot water when the sun is shining, i think I'd dump my money into a bigger battery and forgo the EDDI. Sure, if you have the money for both (or extra panels if you can fit them?).... do that too, but at least you've given it thought as an option. Ultimately a little literal thinking is a good thing in itself ..... even if you decide your original plan is the right one.

  • Moderators, Home & Garden Moderators Posts: 5,469 Mod ✭✭✭✭graememk

    Thermodynamic panels are different to the normal thermal tubes, they are more like heat pumps than direct heating.

    I suppose the immersion only comes on when there is a big hot water demand.

    But even just not having the eddi could be an option, and saving the cash.

    @The devils I suppose your never short of hot water currently?

  • Registered Users Posts: 2,331 ✭✭✭bullit_dodger

    Ah yes - I mentally misplaced that the panels with the evacuated tubes. Still though the question graememk mentions above is the most pertinent, if you have loads of hot water currently on a sunny day, a energy diverter such as an EDDI will be of little use. I'd dump that money into some extra panels (if you have the space) and then a bigger battery after that.

  • Registered Users Posts: 450 ✭✭The devils

    Your right , I'm never short of hot water

    2 adults and 2 kids (not teenagers yet though)

    Really appreciate all your input. Site survey will probably happen in the next week or two and I'll have a decision by then. If I can get extra panels on the roof , that may be a better option

    Thanks I'll let you know anyway

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  • Registered Users Posts: 450 ✭✭The devils


    Rang 3 separate Pv/thermodynamic installers and they reckon stay away from the eddi..wasted money and can be a little complicated throughout the year 👍👍

  • Registered Users Posts: 1,470 ✭✭✭MAULBROOK

    Ah the Devil of over thinking it is kicking in😁

  • Registered Users Posts: 2,331 ✭✭✭bullit_dodger

    Great that they (the suppliers) are thinking along the same lines as the people here. At the risk of blowing our own trumpet, you have some pool of knowledge to tap into here!

    That said, not sure where/what they are meaning with the "and can be a little complicated". it's generally a fairly simple device to be honest. Not much to go wrong with it. It is however, very marginal in terms of "payback" for the average punter who doesn't have thermo panels already in. With you already having a solid hot water solution, it's pretty much a guaranteed waste of wonga!

    Take that €500 and grab yourself 2-3 extra panels for the roof. Maulbrook has effectively coined the expression "go big or go home", but it's pretty true for the panel situation. It's the engine of the whole thing.

  • Registered Users Posts: 450 ✭✭The devils

    Absolutely agree...when they say its complicated, they meant (which I thought)

    Summer timer setting up as immersion only on eddi 9 to 8 say. Winter time say during the night (night saver). But I really dont want it running all night. Look I'll not be going for eddi and leave all well and good with thermodynamic panel, im happy with the ratio ish 1kw for nearly 3kw out..

  • Registered Users Posts: 450 ✭✭The devils

    🤣🤣 definitely

  • Registered Users Posts: 450 ✭✭The devils

    Sorry forgot to mention I purchase the thermodynamic panel from the uk some time ago


    £1250 for system

    €100 delivery

    €800 installed

    I remember I was quoted by a dublin (north side, around Finglas) crowd nearly 7 or 8 k crazy money..