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Posted by okh
at Apr 10, 2015, 1:58:49 PM
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Re: Off grid solutions
Yes, insulation and material use come first. Useful videos (note that one is Australian, so when the video says North, that would mean South in the Northern hemisphere). There are really two different issues here. Neither is black magic. Pretty basic considerations (before starting your SH3D design) run like this:- For anyone designing a new home, net zero (or zero energy or passive house) should/must be considered (legal requirements are getting stricter). That has - as the videos show - profound effects on construction. Thicker walls, floors and roofs. E.g. traditional houses here are built with outside walls in wood some 15+ cm thick. To satisfy modern energy requirements, the same building technique now implies walls twice as thick. Also, orientation of the house, roof angles etc. must be calculated. BTW: What I dislike most about these buildings is that they need to be more or less airtight, which again implies a (mechanical heat exchange) ventilation system to get a half decent indoor climate (and there is still a feeling of being a canned sardine).
- For existing buildings, as you say, it is in practice impossible to achieve the perfect: a zero energy building. But, there is still very much you can do with an existing building to reduce energy consumption (and/or switch to renewable). To take our own (on-grid) example: We put new panelling on the house, added extra insulation/wind-proofing, changed a couple of windows and sealed a few cracks (infrared camera useful). Switching to LED lights and letting two new efficient wood-stoves provide most of the heating was revealing: hot water (long showers) now account for most of the electricity bill. That means we are considering pre-heating hot water via solar thermal collector (water) and/or the use of heat pumps. The long and short of it is a considerable reduction in carbon footprint and considerably lower energy bills (admittedly in part thanks to cheap access to firewood). And all this before we have sacrificed any comforts. If we could kick a teenager out of the shower at half time, the saving would be in the order of € 500 annually. While it will take some time to recover the cost of the investments, it has increased house value, improved environmental conscience, made us more flexible in changing energy sources, reduced our grid drain by half (so far) and we are less vulnerable to power shortages.
All this clearly quite simplified. What is exciting though, is the development of new techniques related to energy and housing. And for planning with SH3D, there are implications to consider: ranging from thicker walls/floors to making room for energy storage (batteries/thermal). Point is, keep such issues in mind before getting distracted by the details of the plan.
ok
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