Public Address | Cafe | Hard News: Going solar?

Aidan

Mon, 28 Jul 2014 12:28:37 +1200

Another thing to carefully consider is the size of the water tank you attach to your panels. Often people are advised to get a larger tank as it can store hot water for longer, potentially covering for a cloudy day or two. The danger of too large a tank is…

James Green

Fri, 25 Jul 2014 15:47:11 +1200

So I've come up with my design for a one household experiment on whether a drain water heat recovery system is worth it. Will update once I have some results
http://distractedscientist.wordpress.com/2014/07/25/drain-water-heat-recovery-weve-ordered-one/

Lucy Telfar Barnard

Fri, 25 Jul 2014 12:57:21 +1200

So, I had a reply from the local distributor I was hoping might pick up importing Dovre. They said "The testing process for the last fire we tested cost closer to $50,000 and the manufacturer will not test any more unless we order a minimum of100 fires . The NZ…

Aidan

Thu, 24 Jul 2014 19:25:32 +1200

Bit late, but we've got a 30 tube/250L electrically boosted system. Here in Canberra (more like Christchurch weather, hotter in summer though) we don't need to boost Sept->Apr. We've got a timer switch in the fusebox for the electric boost, and it comes on from 5.00-6.20pm, and it will top…

Bart Janssen

Wed, 23 Jul 2014 11:20:00 +1200

So who would like a funky wood burner?

When we finally build "the house", you know the one you dream about building but it's never the right time, a funky wood burner would be on the list of must haves.

Just one issue, the one we liked from that web…

Hebe

Wed, 23 Jul 2014 11:03:19 +1200

Funky woodburners wood be wonderful. But first you need to get KDC to get the unachievable and inhumane Christchurch pollution targets brought into line with European cities and allow people to instal cleaner burners — in new builds too.

Lucy Telfar Barnard

Tue, 22 Jul 2014 16:45:55 +1200

The trouble is (if it’s the gyrofocus you’re talking about) it’s pretty near impossible to get an open fire to pass emissions tests. I say “pretty near” because I haven’t heard of any that passed, but don’t know enough to say it’d be impossible. Or it could be they don’t…

Lucy Telfar Barnard

Tue, 22 Jul 2014 11:57:03 +1200

I sent off for a brochure for those focus fires, Bart. The cost of them was eye-watering.

Chris, I agree entirely, though the issue for NZ MfE is mostly about keeping the air clean, with efficiency a by-product of that.

Still, NS3058/3059 measures aerosol mass using a dilution tunnel. Our…

Chris Waugh

Tue, 22 Jul 2014 11:28:06 +1200

According to Norwegian testing standards, it meets our requirements for efficiency and emissions.

Hmmm... Norway. Lots of forest, lots of wooden buildings, properly cold winters, but those buildings stay warm*. If the woodburner is good enough to keep the Norwegians happy, then how could it possibly be a problem in…

Bart Janssen

Tue, 22 Jul 2014 11:18:32 +1200

We always wanted on of these ‘studio’ fires.

If you are just going for looks then this is the fireplace we've always wanted. Of course our little Ahead home really has no place for it :).

Rob Stowell

Tue, 22 Jul 2014 11:06:25 +1200

a small woodburner for my city life, for aesthetic purposes
We always wanted on of these 'studio' fires. They look good, but as our architect affirmed (he put one in in his own huge open-plan Queenstown house) just don't put out enough heat for a big space.

Rob Stowell

Tue, 22 Jul 2014 11:00:58 +1200

Has anyone else ever connected a hot water feed to the dishwasher ?
We do, to an ASKO which claims saving up to 75% of the power in the 'enviro' cycle (which uses a water temp of 55 degrees) when you provide hot water to the machine.
Because we also…

Lucy Telfar Barnard

Tue, 22 Jul 2014 10:39:01 +1200

Grumble grumble bloody EcanNot just Ecan, it’s the whole MfE list system I have issues with. The best that any woodburner on their list can claim is that it’s not quite as ugly as most of the others. Being a pyromaniac, I want a small woodburner for my city life,…

Brent Jackson

Tue, 22 Jul 2014 00:12:37 +1200

With respect to instant hot water from electricity, when we put in the Solar Hot Water System, we looked at getting an electric instant hot water for the kitchen sink (because it was as far from the roof HWC as possible). What I wanted was a thermostat regulated one that…

Shay Brazier

Sat, 19 Jul 2014 12:25:58 +1200

Hi Russell, and other commenters

Russell your question has received a lot of great answers. If I can add one more hopefully useful view and share our lessons from the Zero Energy House. At the zero energy house we assessed the solar on the basis of savings vs increased mortgage…

Hebe

Fri, 18 Jul 2014 17:53:47 +1200

Grumble grumble bloody Ecan. I like those stoves. Filed thanks.

Worik Stanton

Fri, 18 Jul 2014 13:50:43 +1200

I have a friend who has both. Installed the hot water system first and a year later installed the PV. Says now doing it again he would not have installed the hot water system.

Do the research. Price the PV system. Watts per square metre hot water will be better.…

Hebe

Thu, 17 Jul 2014 20:12:58 +1200

Reading the Ecan clean heat appliance regs, it seems that we could put in a wood-fired wetback cooker with radiators in a new build. Which would then be close to my ideal system: wetback/solar PV and running radiators off that and no grid connection.

BenWilson

Thu, 17 Jul 2014 20:01:15 +1200

Cost an absolute fortune.

What? You didn't forge it yourself? You soft city slicker.

James Green

Thu, 17 Jul 2014 17:45:09 +1200

So I think in the public interest, I might invest in a bit more plumbing (so I can bypass our drainwater heat exchanger), and update with some data, both on how much money is saved, and how much efficiency is reduced through fouling.

Steve Barnes

Thu, 17 Jul 2014 15:47:41 +1200

In the first decades of the third millennium, notions of household self-sufficiency , in anything, seem quaint.
And this entire thread seems almost 90s.
Less than 20K
2kw PV panels
60 amp Mppt controller
4.5kw Inverter/Charger
400 Ah Lithium iron phosphate battery stack (600x400x800mm) @ nominal 55 volts (54-58 @…

Farmer Green

Wed, 16 Jul 2014 16:13:00 +1200

In the first decades of the third millennium, notions of household self-sufficiency , in anything, seem quaint.

Farmer Green

Wed, 16 Jul 2014 12:54:01 +1200

But don't forget that those planting trees at a steady rate have older trees which have to be used . Not to mention the odd wind-blow.
And of course communities are far less common than they once were ; a lot of social capital has gone down the drain in…

Lucy Telfar Barnard

Wed, 16 Jul 2014 11:18:18 +1200

Not forgotten by any means (collecting brush and wood, breaking and splitting kindling were all part of my chores as a child), though if you don’t mind spending the money you could get round some of that by buying your wood pre-split. Though of course that eats into the savings.

BenWilson

Wed, 16 Jul 2014 11:14:25 +1200

Don't forget all the wood collecting, chopping and stacking too. You probably should have a decent chainsaw unless you're really handy with an axe.

Lucy Telfar Barnard

Wed, 16 Jul 2014 10:53:05 +1200

a decent second hand wood stove will cover all cooking , house heating , (radiators) and hot water for washing needs, of a large household.

The only problem might be the life expectancy of such a system . . . 50-100 years.
Still , good value for the money.We used…

Lucy Telfar Barnard

Wed, 16 Jul 2014 10:51:21 +1200

a decent second hand wood stove will cover all cooking , house heating , (radiators) and hot water for washing needs, of a large household.

The only problem might be the life expectancy of such a system . . . 50-100 years.
Still , good value for the money.We used…

Jason Kemp

Wed, 16 Jul 2014 09:54:25 +1200

I’m late to this conversation but just in case it is still useful I wrote a few blog posts about solar power in NZ back in Feb/ April last year Is Solar Power for Home Practical for NZ?

I wrote a series of posts at the time and some of…

Bart Janssen

Wed, 16 Jul 2014 09:20:27 +1200

Power companies have imposed a moratorium on new solar connections and want to impose a fee on people with solar installations of around $120 a year. In Arizona the PowerCos tried to impose a $50 per month “penalty” on solar powered houses

This is just the free market system at…

Farmer Green

Wed, 16 Jul 2014 07:52:16 +1200

"Old" technology I know, and perhaps more useful for those who can grow their own renewable energy i.e. trees, but a decent second hand wood stove will cover all cooking , house heating , (radiators) and hot water for washing needs, of a large household.

The only problem might be…

James Green

Tue, 15 Jul 2014 20:16:00 +1200

Either way, you should definitely install it so that it can be easily cleaned (hopefully just a single grub screw that allows you to remove the final plastic section

As you'll see above, not strictly gravity film, and and at least some very mild corrugations to induce turbulence, which enables…

James Green

Tue, 15 Jul 2014 20:07:32 +1200

I remember this article: I bored Beloved senseless about it. Where can the systems be obtained?
I bought ours from a napier company ($425 incl freight)
http://energydrain.vaportec.co.nz/
However, you should probably also read David's comments re: mounting and the inner surface, as on closer inspection, it does seem like this…

David Haywood

Tue, 15 Jul 2014 19:39:53 +1200

Isn’t there a fairly large conversion loss, especially on a battery that’s nearing the end of its days?

Brief reply because feeling very woozy...

My understanding from the electrical guys is that on these batteries the BMS prevents excessive charging as the capacity reduces (not like the old lead-acid batteries…

David Haywood

Tue, 15 Jul 2014 19:32:27 +1200

Thank you! Nova sells a SolarElite system using these panels.

The panels have “flow tubes” but I can’t tell from the comments here whether these are the good sort of tubes.

It appears to be a flat plate absorber not a "heat pipe" system. The disadvantages are:

1. Uses more…

Hebe

Tue, 15 Jul 2014 19:14:15 +1200

I remember this article: I bored Beloved senseless about it. Where can the systems be obtained?

David Haywood

Tue, 15 Jul 2014 19:13:59 +1200

I’m curious about the cleaning issue (many claim to require no cleaning). Is it that the kind of scum that normally builds up in drain pipework reduces the HX efficiency, or another kind of problem?

Yes, the scum reduces the heat transfer. Is your one a gravity film (i.e. mounted…

BenWilson

Tue, 15 Jul 2014 18:42:09 +1200

It’s to be noted that gas is way cheaper than electricity, which changes the (financial) economics if you have a mains gas connection.

Changes again if you don't, though? And changes again if you're making your own electricity at the time :-).

Steve Barnes

Tue, 15 Jul 2014 18:38:15 +1200

Would that work with an instant hot water (all house, rather than shower only) type setup.

Yes, as I described on the previous page. I would suggest a hybrid system of gas hot water on demand, which is far cheaper as you are not storing hot water at around 55c…

James Green

Tue, 15 Jul 2014 17:38:16 +1200

David's is the first piece of skepticism I've come across, so I'm super keen to hear to!
(Plus, I've actually bought, but not yet installed one).
I've spent a lot of time investigating this as, on the face of it, it just seems like a no brainer. And so we…

Russell Brown

Tue, 15 Jul 2014 17:32:42 +1200

You just about had me sold, so I, too, am curious!

James Green

Tue, 15 Jul 2014 17:11:10 +1200

I’ve done heaps of modelling on these systems and they are good in theory. The problem is the HX cost and the cleaning. Most systems use some sort of horrible draino-type stuff every few weeks.

Hi David,
As we are about to install one, I'm curious about the cleaning issue…

Moz

Tue, 15 Jul 2014 15:56:11 +1200

showing forecast bau prices quite a bit higher than most forecasts I have seen lately.

That $120 is $/MWh wholesale in Australia, for those who (like me) needed to look it up. I'm interested in the numbers you've seen so we can compare. The report talks about the price increase…

Andrew C

Tue, 15 Jul 2014 14:56:13 +1200

if it can be done it will be economy-wrecking expensive

I guess I am saying that they are saying it wont be much different to bau prices, yet are showing forecast bau prices quite a bit higher than most forecasts I have seen lately.

It’s also a 40 year forecast,…

Moz

Tue, 15 Jul 2014 14:13:18 +1200

their claim seems to rest considerably on the assumption that their price forecast is not much higher than the bau will be

That's right. Remember that their study is primarily an answer to two claims: first, that 100% renewable can't be done at all; and second: if it can be…

Rich of Observationz

Tue, 15 Jul 2014 14:04:57 +1200

Would that work with an instant hot water (all house, rather than shower only) type setup.

It's to be noted that gas is way cheaper than electricity, which changes the (financial) economics if you have a mains gas connection.

Che Tibby

Tue, 15 Jul 2014 13:47:24 +1200

i've done the math on this time and time again, and the only reason we haven't gone solar PV is that our bills are so low – mid-winter we only pay $150 a month. a large part of that is having a modest home and a big woodburner (total monthly…

Rob Stowell

Tue, 15 Jul 2014 12:54:37 +1200

The cost of building new large-scale generation is likely the biggest driver of solar in the home.

BenWilson

Tue, 15 Jul 2014 12:37:31 +1200

Is there a cost to the electricity supplier (or network supplier) to take excess power out from a house and put it back into the distribution network?

Yes. They do need altered infrastructure if the amount of that power gets large, which it could if there’s a huge growth in…

Andrew C

Tue, 15 Jul 2014 12:20:35 +1200

meaning the price of electricity was lower with 100% renewable than with the current approach

I had a quick scan of their document Moz. Showing prices of $120 by 2020 is considerably higher than most business-as-usual forecasts I have seen. I haven't picked it apart to see what it contains,…

Andrew C

Tue, 15 Jul 2014 12:03:33 +1200

One retailer in Victoria is charging 14c/day if you have solar

Is there a cost to the electricity supplier (or network supplier) to take excess power out from a house and put it back into the distribution network?

I'm just wondering if this is the reason...?

Russell Brown

Tue, 15 Jul 2014 11:44:34 +1200

If you flip me the specs, I’d be happy to have a look at the proposed system for your house.

Thank you! Nova sells a SolarElite system using these panels.

The panels have “flow tubes” but I can’t tell from the comments here whether these are the good sort of…

Rob Stowell

Tue, 15 Jul 2014 11:13:28 +1200

We've had a Thermocell system since 1998. Runs brilliantly. We did blow the controller but that might have been our dodgy power. And Nick gave us a new one.

Moz

Tue, 15 Jul 2014 10:39:01 +1200

What exactly do you mean by this? To be profitable, what happened to the price in this study?

"profitable" meaning people made money out of it. Primarily electricity consumers, in this case, meaning the price of electricity was lower with 100% renewable than with the current approach (subsidised coal and…

BenWilson

Tue, 15 Jul 2014 10:31:04 +1200

Curious about using an idea like that in conjunction with tankless heating. The tankless unit would be right next to the shower. Presumably it would improve the overall flow of the system dramatically to get pre-heated water coming into it, and any issue with fluctuating temperature is controlled automatically.

Moz

Tue, 15 Jul 2014 10:24:19 +1200

One retailer in Victoria is charging 14c/day if you have solar because they own Australia's dirtiest coal plant (Hazelwood) and solar is cutting into their peak demand profits.

BenWilson

Tue, 15 Jul 2014 10:21:56 +1200

Russell, sorry not to have replied earlier but have had bad cold followed by possible “mild” influenza – also looking after children with same.

You too, huh?

Rich of Observationz

Tue, 15 Jul 2014 10:11:04 +1200

2nd-hand batteries from electric cars start to enter the market

Isn't there a fairly large conversion loss, especially on a battery that's nearing the end of its days? (Or are you assuming that the cars will suffer other mechanical failure or be totalled before the battery dies? We should maybe…

David Haywood

Tue, 15 Jul 2014 10:03:35 +1200

A minor quibble, but presumably you’d need to adjust your shower mixer a bit in the early minutes of your shower, as the cold water starts to heat up and so the hot water needed becomes less?

You can put the output of your HX into the HWC (saves energy…

Andrew C

Tue, 15 Jul 2014 10:03:31 +1200

as opposed to people acting out of property value self-interest

I don't think that came into it at all.

NZ is blessed with some great hydro schemes, but it doesn't seem easy to propose new ones nor extend existing ones.

David Haywood

Tue, 15 Jul 2014 09:53:36 +1200

Russell, sorry not to have replied earlier but have had bad cold followed by possible "mild" influenza — also looking after children with same.

I'm going to be annoying by saying that you should definitely install solar water heating — in about the year 2000. Given the problems with time…

Lucy Telfar Barnard

Tue, 15 Jul 2014 09:51:42 +1200

drain water heat recovery...
A minor quibble, but presumably you'd need to adjust your shower mixer a bit in the early minutes of your shower, as the cold water starts to heat up and so the hot water needed becomes less?

Kumara Republic

Tue, 15 Jul 2014 09:49:43 +1200

That was basically killed by environmental NIMBY complaints.

Out of curiosity, what proportion of them are actual environmentalists, as opposed to people acting out of property value self-interest? It's definitely a biggie with wind farms, as was shown in the docudrama The Age of Stupid.

Andrew C

Tue, 15 Jul 2014 09:30:34 +1200

In Australia Beyond Zero Emissions did a major study showing that a transition to 100% sustainable electricity by 2050 would be profitable even with unfavourable assumptions

What exactly do you mean by this? To be profitable, what happened to the price in this study?

Andrew C

Tue, 15 Jul 2014 09:26:54 +1200

Technically NZ should already be at 90% renewable, as we were in the 1980’s. But politically? That’s just not an option

I don't think you can blame it entirely on the politicians. Take a look at "Project Lachie", an attempt to extend some existing hydro capabilities. That was basically killed…

David Haywood

Tue, 15 Jul 2014 09:24:42 +1200

Folks – if it was a ‘no brainer’ to move to solar – every one would do it; instead we have the arguments for/against for trying to save planet/energy/money.
It you have to argue – it is obviously NOT compelling.
So – are we going to save planet/energy/money – or…

Rich Lock

Tue, 15 Jul 2014 02:07:48 +1200

DexterX

Tue, 15 Jul 2014 01:03:28 +1200

On the basis that you roof is corruagated iron – With placing panels on your roof you have to be mindful of the spacing of the purlins – and it is best to put extra purlins around the area where the panels are to be installed to give support when…

James Green

Mon, 14 Jul 2014 22:56:05 +1200

$650 installed
Similar savings to solar
Reference

This isn't spam, I'm just so frustrated that this isn't in the frame. Basically the only people drain water heat recover isn't good for is if you have a new house with a concrete floor and your shower drain is inaccessible. Or if…

James Green

Mon, 14 Jul 2014 22:48:55 +1200

If you are interested in cutting your hot water energy costs, and showering is a big consumer of hot water, you should do this first: drain water heat recovery. Essentially, it's a heat exchanger that goes in the waste pipe below your shower, that uses the heat from that water…

Moz

Mon, 14 Jul 2014 22:27:18 +1200

Maybe green energy isn't a reality after you have looked at the whole picture – a bit like the bio-energy fiasco.

You mean like the 80%+ hydro that NZ ran on for 50-odd years last century?

Josh Petyt

Mon, 14 Jul 2014 22:23:15 +1200

The big option is whether you have a mains or low pressure system
Generally speaking most installations are mains pressure today.

Steve Barnes

Mon, 14 Jul 2014 21:21:16 +1200

I would not recommend getting a solar hot water system from a Power provider,
You will find is that once the power company knows you are not using electricity for water heating they will up your unit cost. One reason for this is that they use ripple switching on water…

Stamper Stamp

Mon, 14 Jul 2014 21:13:23 +1200

Folks – if it was a 'no brainer' to move to solar – every one would do it; instead we have the arguments for/against for trying to save planet/energy/money.
It you have to argue – it is obviously NOT compelling.
So – are we going to save planet/energy/money – or…

Moz

Mon, 14 Jul 2014 20:20:15 +1200

Actually, from a completely different point of view: right now, if I could, I would cheerfully invest in a company or do it myself, if I could buy panels to put on someone else's house. The economics are there, it's just a difficult thing to do in practice because the…

Moz

Mon, 14 Jul 2014 20:05:34 +1200

Folks – if it was a 'no brainer' to move to solar – every one would do it; instead we have the arguments for/against for trying to save planet/energy/money.

The problem is that there's multiple levels that the argument is taking place at. Purely financially, and for a single homeowner…

Lucy Telfar Barnard

Mon, 14 Jul 2014 19:55:46 +1200

Which would, incidentally, be fair – passing on the real cost, rather than slipping it into the usage charges which fluctuate with the price of power.

It would be “fair” in that people would be paying their equal share of the cost. However, the current arrangement is kinder to low…

Chris Waugh

Mon, 14 Jul 2014 19:47:24 +1200

You mean the rest of the world has it wrong? Germany is going solar big time, the UK is heading for 10% of homes, AU is a very solar-friendly country and the US is putting up panels like there’s no tomorrow.

Add China into the mix, where solar water heating…

Jeanette King

Mon, 14 Jul 2014 19:44:34 +1200

Since 1982 I have had solar panels for heating hot water in two houses. On both occasions the installation costs were mitigated by the necessity of replacing the hot water cylinder anyway. The solar hot water heating is supplemented by electricity. In summer I turn the electricity option off. For…

Chris Waugh

Mon, 14 Jul 2014 19:40:46 +1200

Don’t piss around put in one of these big boys

They've been building something similar in Yanqing County in Beijing's northwestern corner (kinda to Beijing what Middlemarch is to Dunedin, I guess), except there hasn't been any visible progress on it for a while now, at least not to this…

Raymond A Francis

Mon, 14 Jul 2014 19:06:28 +1200

Don't piss around put in one of these big boys
http://www.amusingplanet.com/2013/08/the-solar-power-towers-of-seville-spain.html
We went the vacuum tube way a couple of years ago when upgrading bathrooms and water system, it is great. A friend who put in a wet back as well has not paid a heating bill since
There is…

BenWilson

Mon, 14 Jul 2014 18:47:02 +1200

You may feel that electicity prices will drop in the future, but I can’t see that happening.

I can. But it will be solar supply causing it. Every one of you guys going solar is good for me too, because that's one less person competing for the hydro, and even…

Alfie

Mon, 14 Jul 2014 18:44:35 +1200

Maybe green energy isn't a reality after you have looked at the whole picture – a bit like the bio-energy fiasco.

You mean the rest of the world has it wrong? Germany is going solar big time, the UK is heading for 10% of homes, AU is a very solar-friendly…

John Morton

Mon, 14 Jul 2014 18:15:05 +1200

Choosing solar water heating now over PV later might matter if you where using up all your roof surface area (you're not), and there is a significant difference in efficiency between the two — PV is about 15%; I don't know what solar heating is, but it's unlikely to be…

JonathanM

Mon, 14 Jul 2014 18:12:54 +1200

Given your requirements (4 adults, most of whom enjoy long showers) then be careful as capacity is likely your largest constraint. In the summer you'll probably be OK as the sun will reheat things fast enough to not be a problem, but in winter unless you also supplement with electricity,…

Stamper Stamp

Mon, 14 Jul 2014 17:39:32 +1200

BenWilson

Mon, 14 Jul 2014 17:33:45 +1200

However, the only fuel source fast enough to run a zero-storage system is gas

You think? I've used electric versions that were OK. You don't get huge pressure, but I don't want huge pressure. I almost never want it to produce scalding hot water at a high flow rate. For…

Alfie

Mon, 14 Jul 2014 17:20:09 +1200

The power companies will always moan that solar costs them money and that we're somehow leaching off the grid.

The worst example is in Hawaii where conventional grid power is three times the cost of mainland electricity. Power companies have imposed a moratorium on new solar connections and want to…

BenWilson

Mon, 14 Jul 2014 17:19:04 +1200

the fixed supply charge is less than the cost of providing the grid

Therein lies the solution. The fixed supply charge should be the same as the cost of providing the grid. Which would, incidentally, be fair – passing on the real cost, rather than slipping it into the usage…

Richard Grevers

Mon, 14 Jul 2014 17:15:50 +1200

I can't give any direct comparisions since we are several km from the grid. Our hot water is wetback off the kitchen range supplemnented by a doesn't quite work well enough (water pressure too low?) gas califont. From older phhotos the house used to have solar h/w – presumably it…

Moz

Mon, 14 Jul 2014 16:49:24 +1200

The solar customers do pay for their grid use, don't they? Also, they supply power into the grid from their own investment, and at a massively discounted rate. How are they being subsidized?

The argument is AFAIK that the fixed supply charge is less than the cost of providing the…

Alfie

Mon, 14 Jul 2014 16:41:50 +1200

Ben: The solar customers do pay for their grid use, don't they?

You're right Ben. I have a 4Kw grid-tied solar system which cost just over $11k+GST installed and I certainly subsidise Contact Energy. In the summer we're generating 350Kw in an average month, but in winter (north of Dunedin)…

BenWilson

Mon, 14 Jul 2014 16:04:51 +1200

At the moment, non-solar customers are effectively subsidising grid use by solar customers

I don't follow that. The solar customers do pay for their grid use, don't they? Also, they supply power into the grid from their own investment, and at a massively discounted rate. How are they being subsidized?…

Andrew C

Mon, 14 Jul 2014 15:43:58 +1200

At which point you should do a compare with heat-pump hot water tanks

I have two friends who installed heat-pump hot water tanks, and neither have come remotely close to the promised savings. Both regret getting them.

My neighbour below me got PV, and likewise he hasn't see the savings…

Josh Petyt

Mon, 14 Jul 2014 15:41:02 +1200

Some people are now implementing solar hot water, by simply wiring PV panels to a second element in the hot water cylinder with a power controller. Simple dumping of PV electric into the hot water tank.
That sounds smart. You can also then dump excess hot water into a swimming…

Downbeatdan

Mon, 14 Jul 2014 15:12:56 +1200

Good that you're looking at it Russell. I spent a while being a home energy assessor (about 500 homes) and looked at several homes with solar hot water.

The most crucial things in having reliable supply is how big your hot water cylinder is, and when you're going to use…

linger

Mon, 14 Jul 2014 15:06:22 +1200

The drop in grid demand from uptake of solar may not matter so much in the long term, as it could be completely offset by increasing use of the grid for recharging electric vehicles.

Lucy Telfar Barnard

Mon, 14 Jul 2014 14:54:14 +1200

One thing to bear in mind with solar is that the savings may not be as great in future years as uptake increases (unless you’re completely off-grid).

Running and maintaining the grid costs money. At present, that money is recouped through a combination of fixed costs (daily user charges) and…

bob daktari

Mon, 14 Jul 2014 14:36:38 +1200

We're keen to invest in solar at home in some form given the ever increasing power prices

Hadn't planned on doing anything until after the election due to the Greens Solar Power in Homes policy which might be a real thing sooner than later (https://www.greens.org.nz/solarhomes) – which at worst should…

Lucy Telfar Barnard

Mon, 14 Jul 2014 14:07:52 +1200

There’s a nice summary of the relative advantages and disadvantages of solar and heat pump hot water systems on the first two pages of http://www.pce.parliament.nz/assets/Uploads/Comparison-of-solar-and-heat-pump-water-heaters-in-New-Zealand.pdf

Lloyd and Kerr’s paper “Performance of Commercially available Solar and Heat-pump Water Heaters” is here: http://www.physics.otago.ac.nz/eman/hew/econtacts/resourcesabstracts.html .

artig

Mon, 14 Jul 2014 13:56:39 +1200

We bought an almost-new house 7 years ago that had solar hot water installed, together with a gas furnace for supplementing the solar, and for underfloor heating. These were European systems specially imported. There is a hot water cylinder with separate internal coils for the solar heated liquid with its…

Robert Urquhart

Mon, 14 Jul 2014 13:48:57 +1200

I dropped about $7k a few years back replacing the hot water cylinder and putting in vac-tube/glycol (boils at a lower temperature than water for heat transfer at lower initial temperature) system – still requires a little mains power to run the pump. Like Simone, here in Canterbury I can…

Josh Petyt

Mon, 14 Jul 2014 13:34:56 +1200

As it's often said about cars the greenest car is the one you’re already driving.
If you need to replace your HWC then solar hot water may well be the best choice. I trained as an architectural technologist (a fancy name for a drafter and specifier) from ’06~’08 and at…

Lucy Telfar Barnard

Mon, 14 Jul 2014 13:32:32 +1200

where was that electricity actually coming from?

Same place as the rest of it, the wire from the street. It just came off the wire before the wire got to the meter, not after.

BenWilson

Mon, 14 Jul 2014 13:31:24 +1200

With the way projections of dropping cost are going, it looks to me like waiting is the way to go. A strong uptake of domestic solar will drive down domestic power costs, I'd think. And it's not like you're being a carbon using bastard in leveraging off that – you're…

Simone Hindin

Mon, 14 Jul 2014 13:23:50 +1200

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…

Ethan Tucker

Mon, 14 Jul 2014 13:21:02 +1200

...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'?

linger

Mon, 14 Jul 2014 13:14:49 +1200

managed to wire the hot water to bypass the meterwhere was that electricity actually coming from?

Kumara Republic

Mon, 14 Jul 2014 13:09:28 +1200

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…

Brent Jackson

Mon, 14 Jul 2014 13:05:06 +1200

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…

Jon Briggs

Mon, 14 Jul 2014 13:03:39 +1200

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…

Gabor Toth

Mon, 14 Jul 2014 13:03:35 +1200

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…

Rosemary McDonald

Mon, 14 Jul 2014 13:00:27 +1200

For some very informative discussion on solar power and the changes in the technology over the past few years, visit
http://www.nzmotorhome.co.nz/NZMotorhomeForum/viewforum.php?f=55
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…

Lucy Telfar Barnard

Mon, 14 Jul 2014 12:56:31 +1200

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…

DaveC

Mon, 14 Jul 2014 12:53:39 +1200

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…

Simon Adamson

Mon, 14 Jul 2014 12:51:08 +1200

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…

Alan Moore

Mon, 14 Jul 2014 12:47:18 +1200

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…

Lucy Telfar Barnard

Mon, 14 Jul 2014 12:46:12 +1200

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…

Shaun Lott

Mon, 14 Jul 2014 12:44:32 +1200

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…

George Darroch

Mon, 14 Jul 2014 12:41:36 +1200

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…

James Butler

Mon, 14 Jul 2014 12:36:45 +1200

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…

Russell Brown

Mon, 14 Jul 2014 12:28:32 +1200

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

Ooh. How come?

Martin Connelly

Mon, 14 Jul 2014 12:18:21 +1200

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…

Jeremy Andrew

Mon, 14 Jul 2014 12:17:38 +1200

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.…

George Darroch

Mon, 14 Jul 2014 12:10:06 +1200

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…

Tim Michie

Mon, 14 Jul 2014 12:09:27 +1200

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

Russell Brown

Mon, 14 Jul 2014 12:05:23 +1200

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?

Hebe

Mon, 14 Jul 2014 11:40:51 +1200

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?

Graeme Edgeler

Mon, 14 Jul 2014 11:13:36 +1200

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…

Paul Brislen

Mon, 14 Jul 2014 11:09:25 +1200

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…

Public Address

Mon, 14 Jul 2014 11:09:25 +1200

Discussion from blog post.