Evacuated Tubes SHW - Cost / Benefit Analysis « Alternative Technology Assn Forums

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Evacuated Tubes SHW - Cost / Benefit Analysis

(39 posts) (17 voices)

Started 1 year ago by adrian.gab
Latest reply from mick_queensland

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adrian.gab
Member

Hi All,

Keen to hear your thoughts on this topic. Lately I have been going energy reduction mad to work out what would be best for our home.

I have looked into:

- Windows: some form of double glazing alternative i.e. magnetite. We have heaps of large windows in our house. The heat goes straight out of them without thick curtains. Conclusions = way too expensive. Pay off time centuries.

- Lighting: we have old style 12v 50w halogen down lights that the previous owner put in before there was such focus on being green and soaring electricity prices. Conclusions = looking at replacing all of them with low wattage 240v but need to look at price. I think we have 60 downlights.

- Solar panels: still under investigation

- Turning off as many things at the power point: I’ve got some remote control power points that I can flick off the power to a whole plug board which is handy for the study and the electronics in the lounge.

Which leads me to the last thing: solar hot water. We have an electric system that is at least 7.5 years old so I looked into the newer style evacuated tubes for solar hot water. I have been told by the person who quoted me that my current hot water system is most likely accounting for 30% of my electricity bill.

I was quoted $6392 for an Apricus system (30 tubes with 315l Apricus Glass Bottom Element Tank) with installation, not including rebates. The rebates work out to be $1870 less. Bring the total to $4522.

I rounded up all by electricity bills for the last two years (with usage pretty consistent across both years), we are averaging 20.6kWh per day. A 30% reduction in electricity would mean 14.4 kWh per day. Currently the electricity plan I am on charges $0.15598 Inc GST per kWh. That works out be a reduction of $352 per year (20.6 * 0.3*365*0.15598). At that rate assuming no increase in the kWh (yes I know that’s unrealistic) and assuming our electricity usage does not change, that means it would take 12.8 years to pay off. Now if I try be more realistic and factor in a 3% rise every year for the per kWh rate, even then it would take just over 11 years to pay off.

Now I know it is not just about the money. I know that I would be helping along with doing my part to reducing CO2 emissions so don’t get me wrong but 11 years!

If I were to simply leave the cash in the bank, in a 7% interest bank account for 11 years it will have more than doubled (from $4522 to $9518) and will always outperform the savings of the system.

Are my sums wrong am I missing something? Is 30% reduction not real? Is my quote too expensive?

Thanks in advance for any help

Posted Friday 20 May 2011 @ 12:15:17 am from IP #
Lance
Key Master

I have to say I just can't see how any SHW system (and not just referring to apricus here) can cost $7000, it's an insane amount of money for what is essentially a water tank and a solar collector coupled with a pump. You can buy the components individually for a fraction of that price, so either the installation is a huge amount of the installed cost or prices are running way too high.

If you look around (online) you can find 300 litre close coupled systems with stainless tanks, evac tubes etc for around $1000. Even allowing for pump, controller and a bit higher quality in the Apricus and similar systems, there's no way in hell you are getting value for money.

I've said it before, the SHW industry is not charging what they should be, they are charging what the market will bear. Same thing was behind the artificially high prices of PVs until some guys in the industry got tired of the high prices and started doing direct imports. Now you can buy higher grade imports like Suntech for $3 a watt or less instead of the $8 to $10 a watt they all used to charge.

My personal opinion is buy one yourself, install it yourself (it isn't rocket science) and save a few thousand $ in the process. I also recommend avoiding split systems if possible, the number of people who have pump and controller probs with these things is growing rapidly and I suspect the industry is in for a shock in the next few years as more systems fail and need repairs and word gets around that split systems are unreliable...

Posted Friday 20 May 2011 @ 12:25:21 am from IP #
munter
Member

15c seems like cheap electricity. In NSW the flat rate will soon be closer to 25c. On the other hand, if you are running electric now you probably have off peak so the rate might be even lower than the 15c you quoted?

The system price you quoted also seems very high given that it is just a glass tank and electric boosting. As Lance says, perhaps shop around to get a better price and reduce the payback period.

Lance, I know runonsun sell close coupled evac tubes, would you recommend any others? We will be making that decision shortly.

Posted Friday 20 May 2011 @ 12:40:40 am from IP #
Lance
Key Master

I can't recommend anything that I haven't used, but I know there's no way in hell I would pay the standard asking price for a SHW system, especially all the probs people have with them. If I were installing SHW I would be buying a system such as http://www.ebay.com.au/itm/180667689324 or http://www.ebay.com.au/itm/260669336844 and doing it myself.

Posted Friday 20 May 2011 @ 12:55:35 am from IP #
hamish05
Member

You said.....I try be more realistic and factor in a 3% rise every year for the per kWh rate, even then it would take just over 11 years to pay off.

WOW, I would like to become a customer of your retailer.

My price 2007-08 was 12.97 c/kWh
08-09 was 15.54
09-10 was 16.4
10-11 was 18.4
11-12 was 20.5, this is a total increase of 58% over the past 4 years or ave 14.5% per year.

Posted Friday 20 May 2011 @ 1:18:29 am from IP #
Ueee
Member

I was looking a system at http://www.fxlarkin.com.au but again have had no experience with the product so i cannot recommend. The other option (cheaper) is diy check out http://builditsolar.com In my opinion no ATA member should not have a least looked at this site.

In the ACT we have a local electricity/Gas/Telephone/Internet supplier. Currently we pay 14.18c + GST (15.598c) so i'm guessing Adrian is also in the ACT. We are lucky to have the cheapest electricity price in Australia and the best(i think) feed in tariff.

Posted Friday 20 May 2011 @ 1:36:19 am from IP #
Lance
Key Master

I'm paying 22+ cents a kWh for 25% greenpower (can't really afford 100% at the mo) here in Melb, not sure what the price was a few years ago but know I used to get much lower bills (my consumption hasn't changed, still averages around 8kWh a day, including consumption for the business and my partner is home all day), they seem to be slowly increasing the fixed charges here, though not as much as in other states...

Posted Friday 20 May 2011 @ 1:59:02 am from IP #
ecointerest
Member

Hi Lance, everyone. One other factor which I do not hear mentioned is the design of your hot water supply systems to the bathroom and kitchen.

Most people only want to consider one supply connected to both these outlets. This very often involves a relatively long dead-leg. Inevitably that results in considerable waste of water and heat.

If you look at less expensive, gas-operated, point-of-supply, instantaneous water heaters, you could put one very close to the bathroom and another very close to the kitchen. If bottled gas is easy to obtain where you are, it could prove more efficient and less expensive than even the best solar HW system, especially as you would prefer different supply temperatures for bathroom and kitchen.

Just some thoughts for your consideration.

Posted Friday 20 May 2011 @ 2:46:10 am from IP #
adrian.gab
Member

@Lance
The system was $4290, $1850 install, $252 timer supply and install. -$1000 fed rebate, $270 29 STCs @ $30.
I’m not real keen on doing it myself. While I’ve done a number of things myself around the home this one I would not feel confident doing. One thing I like about the Apricus system is the 15 year warranty.

@munter
I am on a flat rate plan at the moment, no peak nor off peak. Always $0.15598 per kWh inc GST. Of course supply charge is on top of this by the supply charge is the same if I use 0 or 1000000 kWhs.

@hamish05
Unfortunately I only have a little over 2 years to compare. I am just on the standard ACTEWAGL plan here in Canberra. In that time I have only had two price rises.
08/09 0.1419
09/10 0.1524 - 7.44% increase
10/11 0.1559 - 2.31% increase

@Ueee
Yes I am in Canberra too. I am purely guessing but I assume Canberra’s have low prices because up until recently ACTEW was the sole provider of energy and water and was heavily regulated by the local government?

Posted Friday 20 May 2011 @ 4:15:31 am from IP #
Lance
Key Master

I haven't checked it, but I'm pretty sure the 15 year warranty doesn't cover the pump, you should look at that, as it's the one component that fails regularly. Fortunately you can pick them up on ebay for around $100 now, but still, it's a pain when things stop working. Also the controller, not sure whether that is under the 15 year warranty either and they also fail a lot (well, the sensors do)...

Posted Friday 20 May 2011 @ 4:21:06 am from IP #
Ueee
Member

Lance,
We also have 25% Greenchoice, cost is 7.5c per kwh , so total greenchoice price is about 23c per kwh, however by having services with ACTEWAGL (Gas, phone, electricity and water) I get 5% off the total bill- which is about half the greenchoice cost. Supply cost is about 54c per day.

Posted Friday 20 May 2011 @ 4:50:34 am from IP #
hamish05
Member

adrian.gab, as I previously said "I would like to become a customer of your retailer", and I seriously meant it.

Down here in Victoria things are "off the rails" with all our cost of services.

North/South pipeline, Desalination Plant, "not so" Smart Meters and lots of others, all stuffed-up by our State Government and costing us a fortune.

But why? because they could.

Posted Friday 20 May 2011 @ 8:25:32 am from IP #
adrian.gab
Member

i got another quote:

3550 same system as in my first post
1628 installation (indicative)
572 time supply and install

total $5750 inc gst

Posted Friday 20 May 2011 @ 9:06:30 am from IP #
sun2steam
Member

You can save the cost for the installation of the timer. It does not save money, if you just have a proper sized tank and boost with offpeak1 tariff.

Posted Friday 20 May 2011 @ 9:08:14 am from IP #
hamish05
Member

My Apricus cost $5652 (b4 Goverment rebates) 18 months ago.

22Tubes x 250L tank Electric boosted.

Rebates have changed since then.

Posted Friday 20 May 2011 @ 9:12:33 am from IP #
kesa32
Member

My System ( AAE-315GLES-30 ) 3o evacuated tubed/ 315L ve tank, this was installed around july last year though "Breaze" , our local enviromental group here in Ballarat Victoria .
Total system cost after rebates was $2500 installed .......it works great when there's plenty of sun, it even works to a reasonable degree in the colder months , but i have 3 women in the household here and they give the hotwater a hiding somedays

All in all its a good system and has made a diffence to our total power bill , and being on tank water will last a very long time ( the first original hws was a 440L twin element and was still going strong when we took it out after 17years! )

We've just ordered a 5KW Conergy power plus system with a SMA inverter........and are hoping to cut most of our power bill out with that and the SHW

Time will tell!

Cheers Ken

Posted Friday 20 May 2011 @ 11:41:39 pm from IP #
hamish05
Member

kesa32 good luck with your PV system. Have you looked at the "Clean Energy Council" Consumer Guide for purchasing PV Systems?

Its a good read, and maybe helpful. http://www.cleanenergycouncil.org.au

Posted Thursday 26 May 2011 @ 1:25:34 am from IP #
katy
Member

Please don't boo me out of your forum as I'm desperate for some solutions. Somehow we are contributing a monumental amount of g-house gases (unwittingly) for a family of 2 adults 2 kids (one teenager so he takes a little longer in the shower but not longer than 10 mins). Embarrased to say (and horrified by cost) but we received $900 for quarter, twice our highest ever bill. This is our first bill in new house and origin have done an estimate which is about 600kW higher than actual reading - that one I can sort out easily. However, still leaves us with using about 3800kW in the 1/4 - which according to my research, av household uses about 18kW/day and comes to around 1600, less than 1/2 of what we are using????? We have a large pool, no air cons, we are careful with lights, have old tvs (2 but usually only use 1 at time) that apparently use less than plas lcd, don't use heaters, clothes dryers and I usually don't spend much time on the computer, oh, and only one fridge. Has anyone got any suggestions as to how we could be using so much power - oh and one of the adults is only here half time? Will look into standby powersavers that i read about on this forum.
Also, I've been researching solar pv panels and also hot water systems to try to take advantage of rebates etc before they run out - or reduce. Has anyone heard on heavenly solar also trading as ecovation, have a good quote from them??? Thanks to your forum have done lots of research and am in the process of asking them lots of questions before we sign up. Also looked at True value - will be avoiding them also thanks to hearing some anti-testimonials in this forum.

Posted Thursday 26 May 2011 @ 1:59:05 am from IP #
hamish05
Member

You said... according to my research, av household uses about 18kW/day and comes to around 1600, less than 1/2 of what we are using????? Those with 18kWh/day probably won't have a large pool.

Do you have an electric HWS?

It would seem that you would benefit from a comprehensive "electrical home usage" audit. You can have a professional do this, or, as I have done, purchase a simple plug in meter (I use a Power Mate Lite) from the ATA webshop. http://shop.ata.org.au/ and do the study yourself.

Good luck, that bill would "put me to bed with a Bex".

Posted Thursday 26 May 2011 @ 2:23:30 am from IP #
Eco
Member

"Large Pool" might be the problem if you are running the pump/filter/heater(even solar) for long periods. There has been a couple of threads on pools on this forum (e.g. http://www.ata.org.au/forums/topic/pool-pumps-how-much-electricity-am-i-using and http://www.ata.org.au/forums/topic/swimming-pools-are-they-a-good-thing-in-our-brave-new-green-world ). Refrigerators (old ones especially) are another big user - though if you transferred from previous house wouldn't account for the increase. Halogen downlight can use 50W each with large numbers for each house.

Plug in Powermeter is a good suggestion. Seen them for sale in supermarkets. Start with measuring the pool.

Posted Thursday 26 May 2011 @ 2:55:13 am from IP #
Lance
Key Master

I agree, the large pool will hav a large pump and a large energy consumption. Pools are a huge waste of energy and water in Australia, it amazes me they are still allowed considering their greenhouse footprint. Try turning your pool pump off over the winter and see what the next bill looks like, I bet it's a whole lot lower. Don't worry if the pool goes a bit green, you can always shock it back to clean with an extra dose of chlorine, but the more eco friendly thing to do would be to convert it to a natural pool (google it, there's a number of companies who can do it for you)...

Also, you might only have one fridge but it might be an energy sucker, older fridges can use several times what a new fridge uses, especially if their door seals are old and/or they need regassing...

The simplest way to find out what's going on is get an energy meter (the plug-in type, not the sensor in the meterbox type, which are wildly inaccurate under many circumstances) and put it on the pool and the fridge and see what they draw in the course of a week. I bet you will be shocked...

Posted Thursday 26 May 2011 @ 3:25:07 am from IP #
katy
Member

Thanks, will try a plug in powermeter - fridge isn't that old and seals seem in good nick. Now we are in winter (as good as) pump isn't getting much of a go either but will be interesting to see. Our trade off for the pool footprint is no air cons = don't know how this evens out!

Posted Thursday 26 May 2011 @ 7:04:27 am from IP #
Sunshine
Member

katy,
If you are in Qld make sure your pool pump is on tariff 33, that will save 40% in power costs.
If you're in another state, ask your power retailer if they have a cheaper power tariff for pool pumps and electric water heaters.

Posted Thursday 26 May 2011 @ 12:34:56 pm from IP #
katy
Member

thanks sunshine - am in Qld - apparently need a sparky to tell me what is on off peak so will get onto that one.
Also read adrian's post talking about downlights - ours are the same - and we also have tonnes of them so will look into changing those. Adrian, did you find any reasonable alternatives? A lot of the LED's i've looked at that can fit straight into socket are very costly - I wanted to reduce footprint but looking into the cost of doing so is getting out of hand?

Posted Thursday 26 May 2011 @ 11:27:29 pm from IP #
Sunshine
Member

katy,
Just look on your bill, it will tell you which tariffs you are on. If it doesn't call your electricity retailer.
It it mentions Tariff 11, then you need a sparky to work out what is connected to it.
Alternatively, you can pull the fuse in the meterbox for tariff 11, and see what isn't working
All appliances which are connected to tariff 11 need to be hard wired in (no plug and socket), so that's another way of working it out yourself.

Posted Friday 27 May 2011 @ 2:43:21 am from IP #
Benny
Member

Katy - have you learned the basis of how to work out energy use ? The powermate type meter is a great idea but you can also do some estimation yourself - especially with your lighting.
e.g. a typical halogen downlight uses 50W, plus up to 10W in the transformer/power supply, so say 60W. If you have this on for 4 hours, then it will use 60W x 4hours = 240 Watt hours. Divide by 1000 and this is about 240/1000 = 1/4 of a kWh (kilowatt hour) and a kWh is exactly the same as a unit on your bills. So if you have a room of 4 50W halogens, then it will use 1 unit every 4 hrs.
Similarly if you can look on the back of the TV (or pool pump) for the power rating in W, you can do the same sums as to how much energy they use over time.

Posted Friday 27 May 2011 @ 6:20:24 am from IP #
amun-ra
Member

sunshine you mean 33 Im sure

Posted Friday 27 May 2011 @ 8:05:04 am from IP #
katy
Member

Thanks Benny - you're a gem - may seem elementary for some, but this is a great help for me. As far as tariffs go, ours clearly states peak or off peak, so that one's okay - i just need to now work out what is chewing up so much power on the peak, but looking on the back on the pump will help a lot with that one - thanks! Will try the fuse also sunshine, thank you.

Posted Saturday 28 May 2011 @ 3:27:17 am from IP #
Sunshine
Member

Sorry all,(thank you amun-ra) I meant tariff 33..
Tariff 11 is the normal uncontrolled tariff.

Posted Saturday 28 May 2011 @ 5:49:31 am from IP #
cnheu
Member

@adrian.gab.

I can assure you the inflation factor of 3% is VERY off.

Just take a look at here: http://www.ipa.org.au/publications/1828/electricity-prices-skyrocket-around-australia, http://news.ninemsn.com.au/national/1028811/electricity-prices-to-rise-by-up-to-64

If the carbon tax comes into play, it could effectively double the electricity price, of course householders will have this compensated, but for people with SHW systems, you just make an even greater profit from savings.

What people don't understand is that WITH or WITHOUT carbon tax, electricity prices will go up, the in NSW it's expected to go up by 40+% by 2013 from 2010, so 14%/year.

So using your numbers:

Cost = $5750 [$/year]
Savings = (20 - 14.4) [kWh] x 0.16 [$/kWh] x 365 days = 327.04 [$/year]
Present Worth Factor (PWF) = (1 - ((1+f)/(1+i))^n)/(((1+i)/(1+f))-1)
if interest 'i' = 0.07 , inflation of price 'f' = 0.14 (conservative)

NPV = cost - savings * PWF

So your system will pay off roughly between 11-12 years. As you've said.
NPV_12yr = $317 dollars (net profit).
If there was carbon tax, and the inflation was 0.2 (20%/year), then you'd be paid off in 10 years.

BUT, if you're in somewhere like NSW, and the electricity prices are already 25 c/kWh, then Savings = 408.8 [$/year], that's a payoff in 10 years, and if there's a carbon tax, you'll be paid off in little over 8 years.

I am happy to type out each equation, but I plugged them into Excel.

Posted Friday 3 Jun 2011 @ 3:00:11 am from IP #

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