We had our solar hot water system installed about 4 weeks ago now. I wanted to wait a little while for it to settle in before writing up our experiences.
We got a Chromagen system – they’ve been around for a long time, and seem pretty well-made and reliable. We bought through Earth Utility, one of the sponsors of the [Sustainable Illawarra](http://sustainableillawarra.com.au/) program we’re participating in. Note that we didn’t get any special deals or anything; we were just another regular customer to them. The service and price were both excellent.
**WARNING:** Earth Utility appears to be in trouble (updated 28-04-2010).
There are two general options with solar hot water: flat panels and evacuated tubes. We went for flat-panel, since evacuated tube was more expensive and we have good direct sun all day. The tubes are apparently more efficient, with a profile of good heat production throughout the day, which makes them great for areas with less sun than us (Tasmania, Snowy Mountains, etc).
We chose a system with a 300L tank, since our 300L electric off-peak tank had never run out on us – that seems to be the right size for our family. Also, we had the old tank turned down to about 60 degrees (minimum temperature), whereas solar systems heat the water to 70-90 degrees, so we’re actually getting more hot water than before anyway (or the same amount of hotter water, which goes further when mixed with cold for showers).
Since the old tank was off-peak 1 (night-only off peak, the cheapest rate), we kept that as the boost for the solar hot water system. The boost for the solar system uses 3 kWh/day, whereas we were using 8-9 kWh/day for electric off-peak, so it’s quite a good energy saving. I’ve now turned the boost off completely and we’re just using solar for heating, so our energy consumption is now zero. Most people around here suggest only turning the boost on during winter or if we get a few days in a row of heavy cloud. The extra capacity should carry us through a day or two of cloudy weather.
I was originally wanting to get a thermosiphon system (tank on the roof at the top of the panels) because that’s the most efficient configuration (no pump is required). It turned out that installation would be very expensive for us, though, since our driveway is too steep for a normal crane to lift the tank onto the roof. So we changed to a split system with the water tank in the back of the garage where the old one was. It’ll probably last longer, being inside instead of on the roof.
Also, in NSW you have to install a tempering valve (temperature regulator) to ensure the water going to bathrooms is kept to no more than 50 degrees. It’s supposed to stop children and other unsuspecting people from burning themselves, since solar hot water can get as hot as 90 degrees. Some people run additional pipes to get the untempered hot water to the kitchen and laundry, but we just got the valve installed straight on the outlet of the hot water system. Hot water at 50 degrees is fine in the kitchen or laundry, and I’d rather keep everything safe for the kids.
We were really happy with the work done by the Earth Utility installers. They routed the pipes really neatly around the hot water unit and up the outside wall, and made sure everything was insulated properly (important for both safety and efficiency). They needed to get electricity to the pump (used to move the water up to the roof and back), so they installed a new double powerpoint near the tank at no extra cost. We didn’t ask for that, they just decided it would be a good idea. How often does a tradesman do that these days?! It’ll come in really handy, since there wasn’t power in that corner of the garage previously.
Overall, we’re really pleased with our new solar hot water system. Purchase and installation were quick and easy, it looks great, and it’s working perfectly. We wouldn’t even notice it was there except for the reduced electricity bills!
Hi Darren,
I was VERY impressed with the service Earth Utility gave you for the solar panel and even more impressed with the savings etc! I did see those evacuated tubes at the Solar hot water evening in Gerringong a while ago. Will be interested to see if you need to turn on the boost on at all over winter! Fantastic stuff! Cheers Chrissy
@Chrissy: I was at the SHW information night too. The tubes do seem to perform better, but it seems to me that flat panels work fine in our climate and are cheaper so that’s what we went with. I was just looking at our electricity bill – we pay about $45 per quarter for off-peak, which adds up to $180 over the year. Allowing for some use of boost, we’ll likely be saving about $150 per year.
Congratulations on your solar hot water! We installed an evacuated tube system last year and it’s worked brilliantly (we live in an area that gets quite a lot of cloud and fog at times). The booster was connected to off-peak tariff, but we’ve rarely turned it on, so I’m going to have it re-wired to the standard tariff to reduce account fees; it hadn’t occurred to me when we installed it that we would use the booster so little, so that’s been a happy suprise. Good luck over winter, hopefully you won’t need the booster too much.
@Em: I like the technology of the tubes, so I’m a bit envious. They just cost more from our supplier, and we get really good sunshine so they weren’t really necessary here. Pity. I’m hoping our booster use (or lack thereof!) is similar to yours! I’m checking out your blog now…
@Donna: Gas is better for the environment than electric, so it’s not too bad. You can get gas boost for solar, too, when the time comes.
Hi Darren,
we currently have a gas hot water system. However i will defiantly choose a solar system when the need arises next time. My parents have had a solar system for years. They rarely turn on the booster switch and there hot water comes out very hot mum is always saying watch out the water is very hot… Have a great weekend. Donna.
Right on! Good post. Solar hot water is quite affordable and depending on several variables can pay for itself in 5-7 years. It works in sunny climates–and it works in cloudy climates. It’s a great entree into renewables. See a basic description and diagram of a system at http://greenhomesamerica.wordpress.com/2008/09/12/shedding-light-on-solar-hot-water/. Note: systems can be designed to work with gas or electric (or propane or wood or….)
Thanks and good luck!
Mike
@Mike: Here in Australia, solar hot water systems don’t work like that. They don’t just preheat the water coming into a conventional system – they completely replace the conventional system. The water recirculates from the storage tank back through the panels, keeping it hot. To handle rainy days, they generally have either electric or gas boost.