After getting my April-May-Jun/Jul electricity bill and almost fainting, I decided to do some experimentation.
The fishroom is under the house. This is an old 70s house, with laundry/storage/car park underneath. The far end has been turned into the fish room (walls and glass slide along door).
This area (mini-rrom) is where I have my fishroom. It contained 4 LARGE windows. Perfect heat releasers.
I went to crazy clarks and bought 10 of those camping mats (the blue foam, silver foil type). I cut these to size, chucked on some glue and attached these, blue facing out, foiling facing in to all the windows.
Nothing else was changed in the room (ie. heater temps, filters etc. over the next bill period)
Surprise, surprise, $40 cheaper (even with the increased indexed rate).
I guess, next winter this may be a good on the cheap money saver. I'll be interested to see how much this keeps the room temp down over winter.
Mitch
Mitch the best insulation IMO is polystyrene. Buy some 20mm offcuts (thicker is better if you can afford it) and cover the windows from inside. Some silicon glue is easy to remove if you ever need to and it will still let in some sunlight through the window. In a situation like yours I made my own walls out of this stuff with amazing cost savings. Easy to make fishroom if you can attach polystyrene sheets to your stumps. The walls dont need to be strutural, just to keep in warmth so I used tank stands themselves and stumps and whatever I could find to glue to.