Heat retentionBefore working on heating, it is vital to minimise heat loss, otherwise any heat just rushes out of the house again. This has two main parts:
- drafts -- do this first. Drafts are a killer
- insulation -- stop heat conducting out
- go around the entire house with a caulking gun and seal up all the skirting-board to floorboard interface with gap filler
- go around the ceilings, and fill all the gaps where the light supply cable penetrates the ceiling
- put door skirts on all external doors
- put rubber seats around all external doors so that they seal
- Install a DraftStoppa on the bathroom exhaust fan
- replace the kitchen exhaust fan with a proper (closing) duct that goes outside the roof
- remove all light switches and power points in cavity walls and seal the cable penetration
- work on the windows to improve their seal
In parallel to this, I have also put a heap of insulation (rockwool) in the ceiling. There was insulation already, but it is old, dirty, compressed and thin and I just laid the new on top of the old, hoping that was adequate. I really didn't want to disturb 40 years of rat urine in the existing insulation! This job is only 1/2 done -- it's very easy to procrastinate going into the roof...
I have also started planning to retrofit double-glazing to some of the windows. For some windows, this will be easy. For some, hard. I'll leave the details of this to another article in the future.
HeatingOnce the house is better at retaining heat, it will benefit from having more heat injected into it. To do this, I have started building a solar space heater from some salvaged material I had. Here's what I've used:
- some corrogated iron, from the carport I pulled down
- some light meranti timber from the pergola I repaired
- Some other salvaged timber of unknown heritage
|Materials I am using, mostly reused except for the roll of plastic sheeting top-left|
|The unit on the roof. I decided to use an existing TV antenna to support it. As we don't have a TV, it's good to see the antenna is finally good for something!|
Next stepI will buy some ducting, and a through-tile to let me get the ducting into the roof. I'll need to work out an air blower and switching. I need to insulate the back of the collector (to reduce heat loss). Note too that the unit needs to be quite well sealed, otherwise cold air will reduce its efficacy.
EDIT: I forgot to mention that I also need to paint the inside of the box matt black, and cover the front with the roll of plastic shown in the photo. I'll also put some small vents along the bottom of the box for fresh air to enter (although another option is for the box to accept air from the house, heat it and return it through a second duct -- I'd rather have fresh air I think).
ExpectationThe collecting area is 3.1 m by 1 m. Assuming I can get it working fairly efficiently, I think it should be equivalent to at least a 1 kW bar heater in the lounge room when it's sunny. It might even be as good as a 2 kW heater. Time will tell...
This post was written by Angus Wallace and first appeared at guesstimatedapproximations.blogspot.com.au