Solar iboost installation



  • zeupaterzeupater Forumite
    5.1K Posts
    Part of the Furniture 1,000 Posts Name Dropper Combo Breaker
    I'm not sure about your logic here. Your £250 may be producing no return but spending that money on a system which may not even pay for itself (never mind produce a return) could leave you out of pocket. If what you want is a return then go into a slightly higher risk bracket (e.g. Peer to peer lending) rather than throwing money at a poor investment. I did my maths on this and for me it did not make financial sense so I shelved the idea. Really hope that batteries will come down to a price which makes that a viable investment instead.

    There's a strong possibility that the efficiency of heating DHW with a gas boiler in the summer has been overlooked. Of course, the actual effiency will depend on a number of factors, but it's highly likely that a modern A rated condensing boiler will only deliver around 50% of the energy potential available in the gas burned as hot water in the cylinder in many homes during the summer, hence the effective cost of the gas would need to be doubled ...

    Taking what should be a pretty conservative ~1000kWh.t of water heating/year from proportional diversion combined with a 4kWp pv system gives an approximate fuel cost saving of ... Gas ~£60/year (0.0298/0.5)x1000 -or- Electricity ~ £100/year (0.1028x1000) ... even at the low energy costs which were raised - and of course, this excludes the standing charges which likely apply to these particular costs.

    Using the figures calculated above, the payback on a £250 propotional diversion system could be considered to be around 4 years (250/60) if displacing gas as the DHW heating fuel -or- around 2.5 years (250/100) if displacing electricity ... even at £500 installed the payback is around 8 and 5 years respectively which effectively means that if the level of return from the solar panels is considered acceptable, there should logically be no major difference in position on a proportional diversion device ....

    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
  • pinnkspinnks Forumite
    840 Posts
    Sixth Anniversary 500 Posts Photogenic Rampant Recycler
    As I have said many times on here, this is my experience.

    I turn my gas off over the summer and based on records kept since 2009 (diverter installed June 2013) save about £80 on gas over those months. Key here is the losses in the pipes between boiler and tank. I also get maybe 60% of my hot water from the diverter over the rest of the year, though what that yields is hard to say given that the GCH is running so the saving will be the on-cost of routing the already heated water through the tank.

    So, 4 years to payback sounds about right.
    Wiltshire - 5.25kWp
    3.5kWp: 14 x Phono Solar 250 Onyx, Sunny Boy 4000TL, WSW 40 degrees, June 2013
    1.75kWp: 7 x Phono Solar 250 Onyx, Sunny Boy 1600TL, SSE 45 degrees, March 2014
  • Exiled_TykeExiled_Tyke Forumite
    599 Posts
    Fifth Anniversary 500 Posts Name Dropper
    To clarify: I was not suggesting that diverters don't pay for themselves. I was questioning why one should be fitted if calculations don't appear to make economic sense. Claiming that it's better than leaving money in the bank isn't logical if the playback calculation doesn't work out.

    The calculations you have both provided are useful but sadly for me I'm not going to get enough usage to justify so will continue to look for other solutions to make the best use of my PV.
    Install 28th Nov 15, 3.3kW, (11x300LG), SolarEdge, SW. W Yorks.
    Install 2: Sept 19, 600W SSE
    Solax 6.3kW battery
  • I've had my Iboost installed for about 20 months now and ported as of right now 2443Kwh to Domestic hot water with no issues whatsoever.

    Takes around 7.5Kwh to heat my standard copper cylinder to "Water Hot" mode.

    Sender unit is still on its original supplied batteries too :-)

    Paid £200 from eBay and fitted it myself.
    4kw PV fitted 4th July 2014 (Green Energy NW £5600). WSW facing, 30 deg Pitch, Unshaded, Samil Solar River inverter, 16 Solar World Mono panels, Iboost on Immersion Heater. located in mid Lincolnshire.
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