The whole system weighed about 460kg when full, although it's a huge misconception that the close coupled systems are too heavy on the roof, never been a job where we had to strengthen the roof; Proof was, when the job was finished, there was three of us standing (all weighing around 80kg), and the roof was still sturdy
The trick is to distribute the weight of the ysstem, by using Tophat, which is the steel bracket across the bottom of the tank.
It was above an old extension to the customers house, was directly above his kitchen, although it was also an older house and was directly above a supporting wall.
When he first contacted us he was replacing an electric hot water, and when he said he wanted a woodfire option I recommended that he go electric boost as well as the woodfire; because there aren't enough systems installed with a woodfire it is not seen as a dedicated booster for solar; so legally it still has to have an electric or gas booster. I recommended the electric boost because if we replaced his electric with a gas boost solar, there is the extra cost of the booster, plus the cost of running gas to the site; and the pressure needed for a solar gas boosted is at least 199mj per hour, so that was $50 per linear meter EXTRA install cost, and the pipe has to be run from the gas meter to the booster. Comparing an electric boost with a gas boost, he paid about $3000 extra.
When the combination of solar and woodfire in Victoria gives you about 95% of your hot water, I told him that he would not make his money back, although we can still do the job if you wanted.
Sure enough, he was happy to pay a fully installed price for $9700 for a 300 litre solar, flue water jacket, 24lpm continuous flow gas booster, running gas to the site, installing a flat roof frame, and integrating all of the gear together.
His rebates were as follows:
20 STC's valued at $30 each for the install = $620
24 VEECs (Victorian Energy Efficiency Certificates) going form electric to gas boost = $720 (Only in Victoria)
Federal electric rebate (only applicable when the insulation rebate has not been claimed) = $1000
Was one huge job as well, my ego skyrocketed when he gave me a bottle of wine for designing the system, and when I found out he was a civil engineer and I didn't slip up!!