Wednesday, April 17, 2013

Solar hot water

With winter fast approaching and our plumbing half finished, it's time to start making some decisions around some of the more expensive items on our shopping list.

First up, the hot water system.

There are basically two ways we can go with this: Your basic run-of-the-mill instant gas hot water service, or gas-boosted solar. While it's seriously tempting to take the cheaper way out (initially, since we'll be buying bottled gas), we've decided to go ahead with a solar system for a couple of reasons, really:

  1. Part of the whole point of building a fully self-sustainable house in the bush is to reduce our dependence on fossil fuels, or resources derived from them. We're completely off-grid for power, water and sewerage and our only fossil fuel requirements will be for the gas cooktop and oven, potentially a gas fridge / freezer, and the odd litre or two of diesel (bio-diesel, hopefully!) for the backup generator.
  2. Since we're on rain water only, our water consumption is going to be a long way below average. It is already really - in Melbourne the average daily consumption target is 150 litres per person, while we get by on about 250 litres per day for a family of five. This means that we can get away with a relatively small solar panel and collector, which reduces the cost significantly.
So with Savva the Plumber on site on Friday, today we made a purchasing decision on the hot water system. We've decided on an Apricus system, which comprises an array of 22 evacuated solar tubes on the roof, a 250L stainless steel storage tank and a 26L/min Rinnai gas booster. After we claim the government rebate on solar hot water installations, we should be able to get this system for around the $3,000 mark, and installed for well under my budgeted figure of $5k.

Next up.. water tanks and the sewerage system!

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