When we first looked at improving energy consumption – the hot water system attached to the granny flat was first on the list to go given that it was leaking.
As part of our changeover to Solar Hot Water, we had a pipe installed to the granny flat to connect it to the house, this pipe went into the ground.
At the time of installation I specifically asked the installer why would they not insulate it – to which he replied “There’s no better insulation then the ground”. That doesn’t apply here though the ground holds a lot of water.
Hot Water being merely Water with energy used to heat it up, also loses that energy by heat transfer – so as we were heating the water up in the tank, we would lose a good portion of that heat in the ground through heat transfer – it would get to the flat in the low 40′s.
So, on Saturday, we got some 3m lengths of 50mm PVC Pipe, and some expanding foam. The pipe was cut along it’s length, so we could wrap the pipe around the copper pipe that was in the ground.
Then, after all the lengths were installed, the expanding foam was sprayed into the pipe, and allowed to expand (it’s awesome stuff – expanded way out of the pipe.
After this, the water temperature was checked, and is now 48oC. Much better result and should have knock on effects in terms of water consumption – hot water faster & hotter – less hot water used. It is 48oC because it’s a requirement of having a solar hot water system that a tempering valve is installed to prevent scalding (else it’d come out at temperatures of up to 130oC.
Lesson learnt here was: What on earth does a plumber know?!
The flat is still set to be demolished though – when we do the extension to the house. Which still seems to be far away, no matter how often and how important one sets the goal to save for it. We’ve made some minor changes to the floor plan that delivers more space for the bathroom at a cost of 0.6m from the already large main bedroom. And I think we are very much at the point where we can get some properly done construction plans with set measurements on it.
I did attempt to put a materials only budget on the renovation and it’s very close to 19k with no labour on the structural work. So allowing something for labour will bring it to around 25k, and probably more – a goal that we are still yet to get close to. A better materials and labour calculator of some sort would be nice.