Going Solar: Lessons from Experience
by Sami Grover, Carrboro, NC, USA 
on 10. 2.08
(One) TreeHugger Goes Solar
We’re not quite at the stage where every roof boasts a solar water heater, as Lloyd has advocated, but there is no doubt that as energy prices rise, solar water heating becomes increasingly attractive. And I’m proud to say that today my wife and I took our first solar showers – yes, we’ve finally taken the plunge and gone solar. Because we weren’t confident enough in our DIY skills, we avoided making our own solar hot water heater, and instead used a recent inheritance (thanks Naini!) to invest in this most practical, and relatively affordable, of micro-generation technologies. Given that there are plenty of readers likely to be interested in renewables for their own homes, I thought it might be helpful to go through our experience. So here’s what we’ve learned…
Firstly, we can say that the installation process was pretty painless. The installers were here for three days, four if you include the fact that work was rained off one day. Besides a little noise coming from the roof and the crawl space, the only intrusion into our lives was a 3 hour period when the water was turned off, and workers occasionally needing access to our attic space for the plumbing.
Secondly, it looks like it should be a good investment. Between federal and state tax credits, it looks like we will end up laying out somewhere in the region of $3,500 for the system – and while we don’t have figures for our typical water heating costs, the installers reckoned it should pay for itself in 8-9 years. With a 25 – 30 year lifespan we are confident that the system will more than pay for itself in the long run (and we’re much happier putting our money in solar than we are in stocks and bonds right now!). Of course, being solar enthusiasts and environmentalists, we’re not necessarily focused on the payback period – as blogger and Transition Town founder Rob Hopkins once commented, payback periods for solar are not necessarily the whole story:
“It is not a question we ask when someone buys a new TV, a car, an i-pod, mobile phone, a swimming pool, a boat, a sofa, new carpets, a DVD player, a jacuzzi, a fitted kitchen, a new cooker, a motorbike, timber decking for the garden, a new conservatory, a caravan, a new fridge, a holiday, a computer, a printer, a double bass, a new chest of drawers or a painting.
Somehow all these things it is OK to buy because we want them, we think they will make us happier, or because we feel we need them. When it comes to solar panels those criteria no longer apply. Odd that. I am buying them because they will increase the resilience of my family, they will reduce our footprint, make us less oil vulnerable, but ultimately it is actually because I want them, in exactly the same way that people want the things on the list above.”
One final lesson we’ve learned during the process is that solar is not always the answer – on asking about solar PV for our house (hey, I’m thinking ahead!), the sales person promptly informed us that he wouldn’t bother. Not because we don’t have the aspect, but because a shade tree is blocking the sun. Apparently the efficiency of PV drops dramatically with a little shade, whereas water heating maintains close to optimal efficiency, even when partially shaded. And while chopping down the tree is always an option, the free service it provides in cooling our house seems awfully attractive compared to a $20,000 investment in space-age technology.
So, overall the experience has been nothing but positive, and there is something wonderful about knowing you are generating at least some of your own power. I'd recommend the experience to anyone with the funds to spare and the appropriate location. Now if you’ll excuse me, I’m off for (another) shower…
A big shout out to my friends at Southern Energy Management who undertook the installation (And a declaration of interest: Southern Energy are a client in my day job).
More on Solar Water Heating
Largest Solar Water Heater With PET Bottles Installed in Parana, Brazil
Solar Water heater Mandate for New Hawaiian Homes
Big Steps in Building: Put Solar Hot Water on Every Roof
Make a Solar Water Heater for Under $5
Home Power’s Solar Water Heating Overview
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Why did it take three days to have the system installed? Here in Australia, it is unheard of for a solar hot water system to need more than one day to be installed.
Ok, so thats a nice overview of the installation, but I have a couple questions.
1) Differences in usage/usability? Unit sizes. Temperature. Type of original unit (gas/electric). Limitations of new unit.
2) With out the tax credits what would it have cost.
I know that first one is kinda five questions, but there all under the usage question.
So, what happens at night when someone wants to get a hot shower, but there is no sun for power. Does anyone know if you can use these systems with a boiler? The hot water in my tank is also used as the heat source for my heat exchange.
Hi,
I have a solar boiler installed some years ago. This hot water is off course used in the kitchen - you don’t need use a much gas/electricity to boil water anymore - and the bathroom. As mentioned in this blog I wondered if we couldn’t use it for other appliances like the washing machine and the dish washer. They use a lot of electricity in order to get the water at the right temperature.
We have a device now that enables you to fill hot water from the sun boiler into the washing machine
Eddy
To answer some of the questions above:
Most systems in northern climates involve a storage tank that is heated by the solar system and another heating source (such as an oil boiler). In the summer, up to 100% of the hot water needs of the home might be provided by the solar system, meaning that the boiler never needs to run. In the winter, it is less, but the boiler may be running anyway for space heating. The solar system can heat the water to a temperature far above what is needed for domestic use during the day (over 140 F) and store it overnight. When the hot water comes out of the storage tank, it goes through a mixing valve to get it to a safe temp. Morning showers are no problem. The reason it often takes 3 days for installation is that there is significant plumbing work to integrate the solar system into the existing plumbing.
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Author's comment:
Thanks Craig! That's pretty much exactly the situation for us - the installers put in two extra water tanks which store the preheated water, and then add those to our existing heater. During the summer it should provide all our hot water needs, and in the winter it will still provide a significant proportion, with the (propane) heater kicking in to achieve the final boost to get it up to temperature. Over the year it should provide 75-80% of our hot water needs. There's plenty of storage capacity so there's no need to change our showering habits.
And much of the installation was indeed plumbing work in the crawlspace, rather than installing the actual panels. The installers estimated that it usually takes two days, but weather, and other scheduling requirements, were not on our side...
Regarding the total cost of the system, without tax credits - I don't have the exact numbers infront of me, but it would have been somewhere in the region of $7,100 or $7,150 - so they make a significant difference.
I think the timing difference compared to Austrailia is probably due to complication. Correct me if I'm wrong, but in NC water freezes in the winter, but in Aus. it doesn't. I know here in Canada the only practical systems are heat-exchangers and the fluid in the panels is anti-freeze. This requires pumps and makes the system more complex than a water-based one. I also seriously affects cost, dramatically slowing acceptance in the north. Payback times up here are on the order of 8-10 years, but in Israel, for instance, (or Arizona I suppose) you'd be foolish not to buy one soon as you can.
To answer some misunderstanding, the solar hot water system is a storage system, not on-demand. It stores up heat during the day, in a tank, meaning anytime you want hot water its there in the tank waiting for you. I'm not sure how you heat your water normally, maybe you don't need tanks in the warmer parts of the US?? But here in Canada everyone has hot water tanks anyway; on-demand systems don't really work, the water is too cold entering the house.
Installations here, in Canada, are supplements to the existing hot-water system, and as such they can supply hot water to anything that has a hot water pipe. (So it would supply water to your washing machine automatically, unless you don't have a hot pipe??) You add them to heat the water as much as they can, but you may still need your existing system to assist. Solar installations are usually geared to provide something like 150% of demand in the summer, but less than 25% in the winter. (Someone in the industry could maybe confirm those estimates?)
Sorry for asking this, but I didn't understood what is a "solar PV".
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Author's comment:
Sorry for the jargon Alex - PV stands for Photovoltaics - or solar electric generation, as opposed to solar water heating or solar thermal. It's very different technology, a lot more expensive and complex. Hope that helps...
Here's another way to crush the ROI naysayer idiots.
Ask them, if oil/gas supplies were interrupted, how much would it be worth to them to have a solar hot water system already in place? Answer: PRICELESS.
Such dumbasses, the masses. When that inevitable interruption occurs over the next few years, and fuel prices in general spike horrendously, DO NOT allow any of those idiots to take a shower at your house.
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Author's comment:
"DO NOT allow any of these idiots to take a shower at your house."
LOL - Thanks Willy. I'll keep that in mind...
Sami, I have a similar situation where most of my roof is almost always in the shade - however, I plan on installing PV by using pole mounts in a location that has a great southern exposure. Keep your options open!
The conflict between shade trees and solar panels could potentially be huge. Ideally, houses should face south and have deciduous trees to shade them in summer and allow the sun to come in in the winter. But what about solar panels on the roof? Trees conflict with those. I would hate to see trees banished from neighborhoods, and it seems very perverse to forego the free cooling you can get from trees. Could we put solar panels somewhere else in the yard, someplace that is sunny all the time? Or have shared neighborhood solar installations? Or invent solar panels that can tolerate intermittent shade? I can imagine yards without trees in Las Vegas or Phoenix, but not in the moister parts of the country, where towering trees are a most precious and valued environmental asset.
I have old radiant heating (1926 home) and was wondering if you think it would be a viable option to go with a solar water heating system?
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Author's Comment:
Hei Eddie,
Thanks for the query. I can't advise on your specific situation, but as far as I am aware there are no reasons NOT to go solar because you have an older home/heating system. Your best bet would be to contact a local supplier and see what they think.
I will ask my fellow TreeHugger contributors though, as many have expertise in this area - will post a response if I find any useful info.
Good luck!
Hei Eddie,
Further to my comment above, TH colleague John Laumer had this to add:
"Most geothermal heated homes and even some air extracting heat pump heated homes (which have natural gas for backup) use hydronic baseboard heat. Solar thermal would serve nicely as a means of increasing the temp of the working fluid before heat extraction or backup system energy is applied.
However, old radiator systems require a strong thermal gradient to achieve gravity based circulation (they don't have pumps). A solar thermal system could not kick out enough btus on a small volume of water to make that happen.
in summary: good for the former but not for the latter. JL"
Hope that helps.
We have a solar water heater here in Arizona. (no brainer for me)
It consists of a black panel on the roof,
and a water heater tank on the ground that may be powered by electricity. (we leave the breaker OFF for at least 50 weeks per year)
The panel has tubing in it that is filled with glycol (coolant or antifreeze) The sun heats the glycol which then is piped down into a coil inside the water tank, and recirculated back up to the panel, thus heating the water.
The tank is insulated and stays hot at least overnight.
It was $4500 installed 2 years ago.
Federal and state tax credits totaled $2,000. (right off our taxes)
the power company kicked in a rebate of another $1,000.
So, our costs were $1,500
That is almost what it costs to replace a hot water heater, if you include installation.
If you consider what a bank certificate of deposit pays on a $1,500 investment, the solar water heater saves us approximately $30 per month, equal to a payback over 50 months or just over 4 years. The savings also increase every time the power company raises their rates.
Yes, it requires some initial investment, but for any-one who wishes to reduce pollution, and reduce dependance on fossil fuels, it's a great way of putting your money where your mouth is.