Tips For DIY Insulation

Here are the notes for a workshop I'm giving at the Kapiti Sustainable Home and Garden Show 27 March 2011

These notes provide a rough structure for the workshop. What I actually say will depend on what participants would like to discuss.

What insulation topic would you like me to cover?

I'll try to cover all of those that I can in the first 30 minutes. I'd like to use the remaining 15 minutes to show off my polystyrene bead blowing system.

My wife and I moved in to our first home in Moera (Lower Hutt) on 16 Jan 2004. Every night since then I've been recording our electricity usage at the mains meter. My plan was to do a bunch of DIY energy saving projects and track how well they works. By 2005 we'd reduced our electricity usage by about 20%.

Before I start I should re-iterate that I'm not a building expert, or a energy efficiency expert - I'm a complete amateur. What I have going in my favour is; (1) I read a lot, (2) I kept data on my projects, and (3) I blogged about the projects on my online diary, - the address is - the background notes for this talk are available on there.

I went to a Sustainable Home Expo show back in 2007 and attended a talk by Grant Dunford of Negawatt Ltd based in Lower Hutt. They really are energy efficiency experts with many years of experience - they specialist in finding the best product to fit a particular energy efficiency or insulation need (they don't sell a particular brand range). At that talk Grant gave his top 10 insulation action priorities (in order):

  1. Droughts - very cheap to address around doors and windows
  2. Underfloor insulation (must be refective - don't use polystyrene blocks only)
  3. Ground moister barrier
  4. Ceiling insulation
  5. Wall insulation
  6. Bath & kitchen extractor fans
  7. heat recovery ventilation (not from roof air though)
  8. distributed heating
  9. double glazing (south and maybe east side)

As it happens I did most of my projects before 2007 so the list of what I did is slightly different:


  • replaced all incandescent lights with CFL
  • insulated water heater
  • curtains
  • draft stopping round some doors and windows
  • insulated ceiling with 2 layers of Batts
  • insulated under floor with polystyrene blocks and "sisilation" aluminium foil (reflective and vapor barrier)
  • Negawatt home energy audit (heat the rooms not the occupants, think about health and energy)
  • Heat pump replaces standard electric heaters


  • solar PV experiment


  • solar hot water
  • kitchen extractor hood above stove


  • installed walls with polystyrene beads
  • double glazing experiments
  • had a baby


  • HERS (Home Energy Rating Scheme) 6.5 stars (out of 10)

We went from 6500 kW/hrs in 2004, down 20% to 5200 kW/hrs in 2005, then up to 7300 kW/hrs in 2009 ("lower energy user" = 8000 kW/hrs)

We're using roughly 2500 kW/hrs per person (each year) since 2005.

Then talk about and demonstrate cheap wall insulation with recycled polystyrene beads.

  • issues
    • flammability and fire retardant
    • electrical wiring (plasticizers)
    • pentane
    • insurance
    • loose vs glued polystyrene (as done in the UK)
  • costs; $25 per cubic metre of recycled polystyrene beads
  • validation with IR camera
  • industry context
Page last modified on March 24, 2011, at 04:46 am
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