Hard News by Russell Brown

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Hard News: Going solar?

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  • Paul Brislen,

    That sounds like a hell of a lot better a price than the one I was quoted this time last year... I wish we'd gone solar then. The sooner you move the sooner you start saving the world/bank balance.

    If you're going to make a change I would. We stuck with the existing gas and it's the only regret I've had in the house build process.

    Auckland • Since Nov 2006 • 200 posts Report

  • Graeme Edgeler,

    Is it viable to wait instead for photovoltaic panels? How will things have changed by the time we’ve paid off the investment in five years?

    Surely, if things get way more awesome in five years, it won't matter that you've done this because, if the theory is correct, you'll still have been saving money. What investment are you worried about wasting if you are saving money?

    Wellington, New Zealand • Since Nov 2006 • 3215 posts Report

  • Hebe,

    I'd love to get solar water heating and PV when we sort out long-term housing. Can anyone recommend a reliable source of information to start educating myself?

    Christchurch • Since May 2011 • 2899 posts Report

  • Russell Brown, in reply to Graeme Edgeler,

    What investment are you worried about wasting if you are saving money?

    Would it make any sense to wait for PV? Would that be a better long-term investment than buying into solar water-heating now?

    Auckland • Since Nov 2006 • 22850 posts Report

  • Tim Michie, in reply to Hebe,

    Try http://www.energywise.govt.nz/products-and-appliances/water-heating/solar for starters..? I've mostly found Energywise useful, if at times condescending.

    Auckward • Since Nov 2006 • 614 posts Report

  • George Darroch,

    I think PV seems like the better option, and that internationally prices of modules are crashing. However, the "New Zealand markup" will be steep, and the installation will be a large part (possibly the majority) of the cost. I have not idea what the actual economics in an Auckland real-world situation stack up to.

    WLG • Since Nov 2006 • 2264 posts Report

  • Jeremy Andrew, in reply to Russell Brown,

    Would it make any sense to wait for PV? Would that be a better long-term investment than buying into solar water-heating now?

    If you're saving money with solar hot water do it. Then in 5 years time, when you suddenly have an extra $123 a month spare, get some PV. It'll be cheaper then, and you won't need as much as your hot water is already sorted.

    Hamiltron - City of the F… • Since Nov 2006 • 900 posts Report

  • Martin Connelly,

    We have both solar hot water and PV panels. The hot water is definitely worth it - but I doubt that its worth borrowing money to pay for PV (It may have been when we installed because the price our electric company paid for our surplus electricity used to be better). The best time to install solar hot water panels on an old house is when you have to replace the hot water cylinder. (At which point you should do a compare with heat-pump hot water tanks). If you get solar hot water - make sure you get vacuum tubed systems - not flat panel systems

    New Zealand • Since Jun 2012 • 28 posts Report

  • Russell Brown, in reply to Martin Connelly,

    If you get solar hot water – make sure you get vacuum tubed systems – not flat panel systems

    Ooh. How come?

    Auckland • Since Nov 2006 • 22850 posts Report

  • James Butler, in reply to Russell Brown,

    Would it make any sense to wait for PV? Would that be a better long-term investment than buying into solar water-heating now?

    I heard once that it's becoming cheaper to install PV and use regular electric hot water than it is to use direct thermal solar hot water, just because plumbing is more expensive than wiring. Depends on your use-case though. If you want maximum utilization of your roof area, then mixing PV and direct thermal will give you more bang because direct thermal is more efficient.

    Mind you I've never run the numbers because I rent, which makes the whole thing a bit academic |:

    Auckland • Since Jan 2009 • 856 posts Report

  • George Darroch,

    Mind you I’ve never run the numbers because I rent, which makes the whole thing a bit academic |:

    Yeah. I think I'll have to get a hut in the sticks before I can afford to contemplate this kind of exercise. However, being small it won't demand such a large system.

    WLG • Since Nov 2006 • 2264 posts Report

  • Shaun Lott,

    Yes, do it. We did the Nova energy deal and it is totally paying for itself. The cost of their power may be slightly more, but everytime the sun comes out, you use less of their power for the same amount of hot water. On balance, we're paying about the same in power bills, but part of that is paying off the cost of the system. The system seems very robust for us so far!

    Waitakere • Since Aug 2009 • 113 posts Report

  • Lucy Telfar Barnard,

    Ooh. How come?

    Possibly because the flat panel systems haven’t had the best longevity in the New Zealand sun (http://rustypanels.blogspot.co.nz/). Though I’ve heard the vacuum tubes are better anyway, as they make better use of the sun over the full course of the day.

    We’ve had a flat panel system for about 10 years (and yes, we have a fair bit of whiteneing as per the rustypanels problem, though it still seems to perform OK), installed when there was effectively a 2-year interest-free loan available.

    When you’re doing your sums, don’t forget to factor in the maintenance. Our pressure valve seems to need replacing regularly, which isn’t cheap and has probably taken a fair chunk out of the savings.

    Unfortunately we can’t tell how much money we are saving. We had to rewire not long after it was installed, and discovered from the electrician that at some point in their 50-year tenure the previous occupants (who’d raised nine children there) had managed to wire the hot water to bypass the meter, so our previous year’s bills didn’t include hot water to compare with.

    Wellington • Since Nov 2006 • 585 posts Report

  • Alan Moore,

    I set about a few months ago to model the financial gains of PV and it was a real nightmare - there are so many variables. I ended up with an 8 year payback as we only have a monthly lecky bill of $110.
    It doesn't help that we have built a low carbon house - no gas - so cooking is a big hit.
    However my recommendations are that if you want to go with PV you need to run everything you can on timers....water heating and all the appliances you can - dish washer, washing machine, freezer(?) etc. These need to run during the day when you're making electricity as storing it on the grid quickly becomes too expensive......and change to Meridian!
    AC micro-inverters and power out systems are coming too which are great steps forward.

    New Zealand • Since Oct 2013 • 5 posts Report

  • Simon Adamson,

    When our 40 year old hot water cylinder died 2 years ago I figured there must be better options than replacing it with basically the same technology that was used in the 1970's - an electric cylinder is essentially just an enormous kettle after all. Checked out solar first assuming this was the best option - Energywise and Consumer websites being my trusted sources. When the Energywise promotional casestudy had a family describing how if they were really careful about what time the washing machine went on and they were really careful with showers then they'd usually manage without running out I was pretty unimpressed. The heat pump option looked a lot better, with equivalent price savings and greater reliability . Head pumps have been such a revolution for space heating, it makes sense that they have something to offer for water also - you're still using grid electricity, but much less of it, and in NZ most of that is generated via renewable sources.

    Total cost was around $8k - $5K for the heat pump and $3k for a replacement giant kettle - frustrating that there doesn't seem to be an option to have a simple water storage cylinder. I put it on mortgage - $3K was the minimum I was going to have to pay for a replacement anyway and the option I took of spending the additional $5k will be paid off in about 8 years by the $70 a month in power saving that we've redirected to the mortgage.

    Good luck with your decision Russell, our choices on home energy use is one of the areas we can all make a real impact on carbon emissions etc.

    Christchurch • Since Jul 2012 • 6 posts Report

  • DaveC,

    Assuming you're in the Vector area, the Vector solar deal http://vector.co.nz/solar is much better value. You get about $35k worth of panels and battery for a low up-front price and a small monthly payment. The battery means you use more of your generated power directly, rather than having to take whatever pittance the power company wants to pay you for selling it back to the grid. You never own the system but by the end of the trial there will be something much better available anyway.

    Since Nov 2007 • 22 posts Report

  • Lucy Telfar Barnard,

    Oh, yes, good point Simon. I remember going to a presentation from a Dunedin scholar in Bob Lloyd's team, who annoyed a number of pro-solar audience members by pointing out that hot water heat pumps were a Good Thing and saved more than solar because they saved money all year round, including in winter when people probably want more hot water.

    The other thing I'm also remembering from when we crunched the numbers (pre-hot water heat pumps) was that a solar hot water system made sense if you needed a new hot water cylinder anyway, but didn't otherwise. But as noted, that was 10 years ago.

    Wellington • Since Nov 2006 • 585 posts Report

  • Rosemary McDonald,

    For some very informative discussion on solar power and the changes in the technology over the past few years, visit
    and search "Solar"....and stand back!!!

    Some of these guys are totally commited to solar power, but acknowledge the potential pitfalls of poor installation and management. There is some discussion on domestic solar power, and on the viability of the 'sell back power to the grid' schemes.

    On solar water heating.

    Forty years ago the Eastern Bay of Plenty Electric Power Board offerred intrest free loans on solar hw systems.
    We got one installed, a flat panel system, worked a treat.


    Combined with a wetback system on the fire during the winter....

    Had the whole Family Carers issue had not gone so tits up for us, we would have installed solar hot water in a heartbeat.

    Waikato, or on the road • Since Apr 2014 • 1346 posts Report

  • Gabor Toth,

    If you have some basic D.I.Y skills and have half-decent access to your roof cavity and basement, you can still save hundreds of dollars installing your own insulation. I did both our ceiling and underfloor and calculated I saved over $1000 (even with the EECA subsidy taken into account) for what was a couple of weekends of work. It also means that you can choose the insulation type that suits you best rather than whatever system an particular professional installer is tied to (which for them tends to be a cover-everything blanket / wrap type system as they are the fastest to install using largely unskilled labor). For instance I installed "GreenStuf" between joists underfloor rather than a wrap system as wraps can make access to plumbing and wiring a complete PITA if you need to get to them.

    Wellington • Since Dec 2006 • 137 posts Report

  • Jon Briggs,

    We put in solar hot water as part of our house extension a few years back. No idea if it has worked out as value for money considering the initial outlay, but it certainly slashes the power bill in summertime. However, it does turn something simple that never requires thought into something complex that requires maintenance. We have had technicians out to look at our system a few times and not had hot water when we needed it 4 or so times (when people are staying with us or at the end of the summer when settings need adjusting) with the new system.

    The system does achieve what I believe to be its true purpose though: raise the enviro-status of our household (I hope my wife is not reading this!!!). We will have to park a Prius out front next ;)

    Since Dec 2008 • 27 posts Report

  • Brent Jackson,

    We have had Solar Hot Water heating for about 8 years now. We needed to move our existing HWC (hot water cylinder) as we re-developed our kitchen, and decided to go Solar. The maths at the time ($7500) was such that financially it was not worthwhile as the loss on interest on the capital outlay was less than the projected savings. But we got it anyway because we could afford it and wanted to do our bit for reducing CO2 generation. However, the price of electricity has gone up, and interest rates have fallen a lot, so it probably has paid for itself.

    We turn the electric element in our HWC off sometime in November, and don't usually turn it on again 'til April. This means we have $80 to $90 electricity bills over summer (family of 4 with 2 teenagers). In winter this goes to $150 or so, because we do use electric heating, (though we do not keep the house at a comfortable temperature all the time - we wear more clothes). Whenever I've discussed this with people they've been astounded that our bills are so low.

    We got an Edwards Solar system, which we chose because it has a separate gycol system which is heated by the sun (ie the sun does not directly heat the water). My mother and brother have each had problems with systems that heat the water directly.

    Hope this helps.

    Auckland • Since Nov 2006 • 620 posts Report

  • Kumara Republic,

    In the words of Bucky Fuller, "You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete." And solar panels are just one of those new models taking steps towards micro-generation and getting off the grid, thus reducing dependence on publicly listed powercos who only answer to faceless shareholders.

    The southernmost capital … • Since Nov 2006 • 5446 posts Report

  • linger, in reply to Lucy Telfar Barnard,

    managed to wire the hot water to bypass the meter

    where was that electricity actually coming from?

    Tokyo • Since Apr 2007 • 1944 posts Report

  • Ethan Tucker,

    ...to be paid off at $123 a month as part of our electricity bill with Nova over five years

    Does that mean you're stuck with one electricity provider for five years though? Is there an affordable way of going 'off-contract'?

    Wellington • Since Apr 2008 • 119 posts Report

  • Simone Hindin,

    We've had exclusively solar/wetback water heating in our house since building it in 2006-7 and its (mostly) great - since installation we have never turned on the electrical heating for the water. We have the vaccum tubes system which I believe is supposed to be more cold resistant - still warming water on sunny but cold winter days which can be common in mid-Canterbury. The only problematic periods are spring and autumn when its not really cold enough to run the log burner and not warm/sunny enough to build up enough hot water. Sometimes we run the burner and open the windows. Also, we're a two-adult no children household so probably don't use as much hot water as some. Mid-winter we occasionally have the opposite problem of too much hot water from the wetback which is why we put in a deep soaky bath.

    Christchurch • Since Mar 2009 • 6 posts Report

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