It’s been 2 months since the last post and we’re warming up into spring. Cheap Geek still has not finalised the last bit of roof insulation, though I’m pretty sure we’ve got too many Green Stuf batts. Cheap Geek plans on stowing these above the original layer of insulation, but one batt already has the privilege of being stuffed up our chimney.
According to yourhome.gov.au, ‘heat energy goes up the chimney and large volumes of cold air are drawn into the room to replace it, creating cold draughts or removing heated air from nearby spaces.’ And with chimneys, not only does heated air get replaced by cold air, the resulting draught also makes you feel colder than it actually is.
Hence the need to put a bat(t) up the chimney:

Cheap Geek measured up the chimney interior and trimmed the batt to size so that it would fit snugly without being squished*. Once inserted, it blocked out most (if not all) draughts.
Before putting insulation in your chimney, make sure that it is hypoallergenic. Glass-wool batts, for instance, are not a good idea: they can shed irritant particles. Fires are also not a good idea whilst the insulation is in place.
There are purpose-designed products such as Chimney Sheep or Chimney Balloons that will keep the draughts out and the heat in but they’re nowhere near as fun as roping water bottles together whilst stylin’ in a beat up leather jacket and 80’s hairdo.

*Condensing an entire batt will compromise its ability to insulate.