Dec 11, 2016: Episode 7 – New Windows in Old Walls

We’re getting close to Christmas and making slow but steady progress on the energy retrofit of the old fibro cottage next to the Greeny Flat. We were slowed down for a while by some tricky flashing and cladding details around the front porch and the curved wall next to it (see Episode 6 here). Plus I’m involved in three different Community Renewable Energy projects in our area which require some of my time and attention. But we’re pressing on with replacing the windows in the last two walls and hoping that we can get the cladding finished before the end of the year.

In Episode 7 of our series of short videos about the project you can see how this process is quite a bit more complicated than the earlier window replacements where we simply fitted the new window into the old opening (see Episode 5).

The good news is we’ve only got three windows left to put in but we’re into the tricky ones where we’re not just replacing the old window with one of the same size. On the north and west walls we’re changing the size of most of the windows and adding some new ones that weren’t there before. We’re trying to move the house closer to the ideal window arrangement for Passive Solar Design (you can read all about that here) which means reducing the amount of glazing on the west side and increasing the amount that faces north.

Due to council restrictions relating to heritage conservation we weren’t able to add quite as much glass on the north side as we would have liked. Instead we’re doing a couple of innovative things with the north wall including placing a window directly in front of the old brick chimney to create a mini Trombe Wall for winter heat storage, and using the entire clad portion of the north wall as a solar air heater. I’ll get into this in more detail in the coming weeks. For now it’s reassuring to note that the sun does not contact the north wall during the day in summer because the house has the correct amount of eave overhang. This means that our solar air heater plan for the north wall in winter will not overheat in the summer.

The north wall of the cottage at solar noon (1pm during daylight savings time) on the 1st of December. Note how the roof overhang is shading the whole north wall in summer. In winter this wall will be in full sun and we’ll be able to collect the hot air from behind the cladding and pipe it into the house. This will help heat the house as well as providing fresh air in the winter when the windows and doors are kept closed.

Thanks for your interest in the project. We’ll continue to provide more details about the Trombe Wall and Solar Air Heater concepts as we progress over the coming weeks.