Browse Forums Heating, Cooling & Insulation 1 Aug 22, 2016 5:05 pm Any recommendations for solar hot water? I have no idea what would suit our family of 7. Any advice is appreciated. Re: Solar hot water recommendation. 2Aug 22, 2016 8:26 pm Apricus 30 or 40 evacuated tubes with 400 litre tank, with mid electric boost. If you have solar pv on net feed in tariff run the electric boost only during the day. Some might recommend gas boosting, but if you are not on town gas, i.e. on bottle gas, it'd be too expensive. Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Solar hot water recommendation. 4Aug 23, 2016 9:18 am I didn't ask what area would it be in, far north, or far south in this large continent of ours. If in the chilly climates, then forget about heat pump hotwater systems, as you'll forever need to run them on boost, costing you a lot more money to run. Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Solar hot water recommendation. 5Aug 23, 2016 1:44 pm Thanks. we are in South East qld. Winter gets to 0 or below. I've had a couple of quotes on evacuated tube. Do you know what the difference is between mid and bottom boost. Re: Solar hot water recommendation. 7Aug 23, 2016 8:40 pm Thanks. we have had such different quotes and recommendations. Wasn't keen on heat pumps. We will be on tank water so we are going to be water wise. Re: Solar hot water recommendation. 8Aug 25, 2016 11:11 pm Craigasaurus Thanks. we are in South East qld. Winter gets to 0 or below. I've had a couple of quotes on evacuated tube. Do you know what the difference is between mid and bottom boost. As you might have noticed with my sig I'm in SE Qld as well... I've got a Apricus 30 tube, 315 l tank that is mid mounted element.... mind you there's only two of us in the house, and we only had to boost once last year, 7 people in the house means you'll probably go on boost a few more times than me. Tank water sounds like you do not have town gas, so don't get gas boosting, it'll cost you. Mid boost as you can guess means the element is roughly halfway up the tank, and therefore only boosts the top half of the tank. Bottom boost, boosts all the tank. So if you draw say a kitchen sink of hot water in the night, then the element will boost heat that water. A mid element won't start boosting until the water in the location of the element cools down. We actually turn off the boost element on the wall next to the tank, so we know when it actually gets boosted. Morning showers means most of the heating will be done via the tubes, night showers mean electric boosting. In our old place, we had hot water boost on a timer, that only allowed it from 4pm to 6pm, so we knew we'd always have hot water. Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Solar hot water recommendation. 9Aug 26, 2016 6:04 am Thanks that very informative. We've never had solar hot water before so have no idea about it. We all shower at night. at 5 minutes each. Why would the night showers be boosted? Re: Solar hot water recommendation. 10Sep 02, 2016 9:48 am when you use the hot water of a night, the water in the tank is replaced with cold water, and solely heated up by the boost element (unless you put a timer in, so that it'll only electric boost at times that you want it to). Morning showers means that the sun is up, and most of the heating is done by the sun instead of boost. FWIW, we had the boost on timer that was set to only come on between 4 and 5pm, so that it only really boosted if there was no sun that day. Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Solar hot water recommendation. 11Sep 02, 2016 10:16 am We are also interested in this. Thanks for this great info! We still live in our shed and we use gas bottle and it just costs too much! For the house, we will be getting solar hot water. We probably will do the same for the shed later on though it will not be lived in like how we use it now once we moved to the house. We just want to totally steer away from using gas bottles. Owner Builders in boot-shaped Yorke Peninsula : viewtopic.php?f=38&t=80264& Re: Solar hot water recommendation. 12Sep 02, 2016 10:39 am Just thinking if the shed in future is going to be primarily shed, but you want hot water there, then perhaps instant gas might still be the better option? If the shed hot water is only going to be used on random occasions, I think you'll find solar is just too expensive to install. A simple hot water tank, even a small one needs to be boosted regulary to maintain the 60 degrees in it, and that's probably the cheapest to install storage hot water. All a matter of doing your sums to see what is going to work out better for you in your shed in the future. For the house, solar hot water with electric boost if you are not on town gas is the best choice. Personally Evacuated Tubes is my choice.... come heavy hail storms, you may on a rare occasion break a tube, but you won't lose any water, versus flat plate solar can cause a loss of water. Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Solar hot water recommendation. 13Sep 02, 2016 11:01 am You are right, at the moment it is really a pain probably because we use it heavily. We run out of gas every 3 months and it costs us $140 each bottle. But just a few days ago, our gas bottle ran out after using it for only a month! We are thinking there is a leak somewhere but partner cannot seem to find where and what. Anyway, we are awaiting for our plumber to come up in a couple of weeks to do second fix for the house so we will ask them to look at it as well. For the meantime, we turn off our gas bottle at night before going to bed hahaha and before leaving the house during the day. So annoying. Owner Builders in boot-shaped Yorke Peninsula : viewtopic.php?f=38&t=80264& Re: Solar hot water recommendation. 14Sep 19, 2016 12:24 pm Evacuated tubes are great but are a bit over the top for a sub-tropical climate like ours in SE Qld. Good old panels are fine. We have a 320L Solahart with two panels, however we only have a family of two. Ours is electrically boosted with a thermostat but because we are only two people and it is a large tank I have switched the electric circuit off - we always have steaming hot water even without it. If you have a large house I would consider having two hot water systems, one serving each half of the house. This will reduce pipe length from the tank to the hot water tap, thereby reducing "dead legs" so you will waste less water. Otherwise you might have to run the tap for 30 seconds to get hot water in your furthest bathroom/laundry/kitchen. With the electric element, you can have it on an off-peak tariff, but it doesn't really make that much different for a solar water heater because the element won't come on during the day anyway because the water will be hot from the sun. Contrary to what bpratt said (sorry mate) I wouldn't recommend running the element during the day only and not at night. The tank temperature needs to be kept above 60 degrees to avoid legionella. If you have a large family, chances are several people are going to have an evening shower/bath. Therefore it is likely that your tank temperature will drop significantly at night if you don't have the secondary energy source available to keep the tank temperature up. My recommendation would be to use solar primary heat source with an electric element secondary, with the thermostat set on 60 degrees for the best energy efficiency. I'd run it on Tariff 31 or tariff 33. Building Services Engineer Renovating our 1960's modernist home in Brisbane https://forum.homeone.com.au/viewtopic.php?f=53&t=82091 Re: Solar hot water recommendation. 15Sep 19, 2016 8:49 pm 1960sModernistHome Evacuated tubes are great but are a bit over the top for a sub-tropical climate like ours in SE Qld. Good old panels are fine. Contrary to what bpratt said (sorry mate) I wouldn't recommend running the element during the day only and not at night. The tank temperature needs to be kept above 60 degrees to avoid legionella. If you have a large family, chances are several people are going to have an evening shower/bath. Therefore it is likely that your tank temperature will drop significantly at night if you don't have the secondary energy source available to keep the tank temperature up. My recommendation would be to use solar primary heat source with an electric element secondary, with the thermostat set on 60 degrees for the best energy efficiency. I'd run it on Tariff 31 or tariff 33. Never really liked the plate collectors, as if they get broken, there goes the hot water. Break tubes, and you don't lose any water.... or are there now plate collectors that don't lose water when broken ? In my situation, the hot water is plenty hot through the night for us, and by the time it starts to chill down, i.e. cold water coming in to the tank from hot water drawn off to drop the temperature, it isn't an issue for us. If the OP is using the water after the sun goes down, then electric boosting of a night is then essential for the reasons described. Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Solar hot water recommendation. 16Sep 19, 2016 9:08 pm bpratt 1960sModernistHome Evacuated tubes are great but are a bit over the top for a sub-tropical climate like ours in SE Qld. Good old panels are fine. Contrary to what bpratt said (sorry mate) I wouldn't recommend running the element during the day only and not at night. The tank temperature needs to be kept above 60 degrees to avoid legionella. If you have a large family, chances are several people are going to have an evening shower/bath. Therefore it is likely that your tank temperature will drop significantly at night if you don't have the secondary energy source available to keep the tank temperature up. My recommendation would be to use solar primary heat source with an electric element secondary, with the thermostat set on 60 degrees for the best energy efficiency. I'd run it on Tariff 31 or tariff 33. Never really liked the plate collectors, as if they get broken, there goes the hot water. Break tubes, and you don't lose any water.... or are there now plate collectors that don't lose water when broken ? In my situation, the hot water is plenty hot through the night for us, and by the time it starts to chill down, i.e. cold water coming in to the tank from hot water drawn off to drop the temperature, it isn't an issue for us. If the OP is using the water after the sun goes down, then electric boosting of a night is then essential for the reasons described. Our plate collectors went through Brisbane's very bad hail storm in Nov 2014 and were fine. Our commercial-grade Klip-lock roof was worse for wear though... The evac tubes are good, no doubt about it, but the extra expense for efficiency is not really necessary for our northern climate. As for the element, I agree for a small hot water demand it would probably be fine to run it only during the day. I actually turn our element off at the circuit breaker for 8 or 9 months of the year and we still have (literally) steaming hot water. Building Services Engineer Renovating our 1960's modernist home in Brisbane https://forum.homeone.com.au/viewtopic.php?f=53&t=82091 Re: Solar hot water recommendation. 17Sep 22, 2016 6:21 pm 1960sModernistHome The tank temperature needs to be kept above 60 degrees to avoid legionella. So how does this work for solar hot water without a booster or with a gas instantaneous booster under heavy usage where the tank temperature will drop below 60 degrees. Is the occasional raising of the tank temperature to 60 degrees enough to keep legionella at bay. How occasional does this need to be ? Every several days, once a week, ... ? Re: Solar hot water recommendation. 18Sep 22, 2016 7:46 pm Most modern systems will have automatic boost with a thermostat, so if the tank drops below the set point (say 60 degrees) the element or gas flame will operate until the temp goes back up over the set point. With an older system with manual boost only, that might be an issue. I'm not expert enough on legionella to be advising on that in any more detail. Building Services Engineer Renovating our 1960's modernist home in Brisbane https://forum.homeone.com.au/viewtopic.php?f=53&t=82091 Re: Solar hot water recommendation. 19Sep 22, 2016 9:06 pm I believe instant gas boost requires it boosted to 70+ degrees to deal with legionella in a shorter time frame, which is then cooled back down to 50 degrees via the tempering valves. Likewise, I'm no expert on legionella either ! Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Solar hot water recommendation. 20Sep 23, 2016 8:06 am bpratt I believe instant gas boost requires it boosted to 70+ degrees to deal with legionella in a shorter time frame, which is then cooled back down to 50 degrees via the tempering valves. Likewise, I'm no expert on legionella either ! Yeah you'd think that a daily "purge" (for lack of a better term) would kill off the nasties. Realistically legionella not a huge problem in domestic. But when we have reticulated warm water systems for hospitals, aged care facilities and the like, that is when it becomes a serious (and tricky) issue to manage. Trying to strike a balance between eliminating hot water scald hazards, and keeping the water hot enough to kill bacteria, can be an engineering challenge. You then end up with a building full of tempering valves that need regular testing and maintenance (which is an ongoing cost). Building Services Engineer Renovating our 1960's modernist home in Brisbane https://forum.homeone.com.au/viewtopic.php?f=53&t=82091 the sun master is the solar heating to "warm" the water in the tank the S26 is your hot water system which will heat the water (25 degrees?) so with both turned on you… 2 12547 I want to build a decking to the drawn shape outlined in black. 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