WHICH IS A BETTER IDEA?

– 6 stars to 7 stars (cost $16,000 to $87,000)
– Save 330 to 950 kW, 300 to 900kg CO2, $80 to $230, per annum
– Nice payback period (not)

– 1 kW of additional PV in NSW (cost $300 – $500)
– Reduce grid consumption by 1,400 kW
– Sensible idea

– Blower door test (cost $450 to $1,000)
– Give us a way to measure performance, improve building practices, real savings not paper
– Make accountable

#building #architects #energy #windows #blowerdoor

natHERS Assessors and Architects!

Architects, how are your designs going to go with glass to floor ratios of 20% (you would be currently 40-60% and randomly higher) —I am not qualified to give financial advice but ……. time to buy shares in companies that have thermally broken windows.

The RIS for energy efficiency reckons the costs will be approx. $2,000 – $3,000 to go from 6 to 7 stars. (Some dream world where cost benefit analysis & the BCA meet)

I used 3 of my recent ratings (2 project builders & 1 custom builder) and changed them to 7 stars and worked out the cost difference range to be $16,000 (small house/perfect orientation) to $87,000 (large two storey/not the best orientation due to the lot purchased by the owner) or 2.5% to 12.6%.

The RIS used glass to floor ratios of 15% to 20%, and is really only reporting insulation and ventilation (ceiling fans & roof ventilator) costs as the cost to upgrade and did not include real world markups & gst in the costs.

My ratings are real houses, real builders costs etc.

Whilst I agree with improving buildings performance, don’t know that 7 stars is the best idea, PV and blower doors. These would be far lower cost and far more measurable and realistic.

What do they say “If you aren’t keeping score, you are just practicing” natHERS certificate is a bit of paper that says if correctly built, it would achieve x stars, but we have no method of testing or checking this.

#building #architects #energy #windows #blowerdoor

NCC (BCA) 2022 proposed Energy Efficiency changes

Need your opinion?

All new & prospective home buyers/builders out there, are you aware of the proposed changes to the 2022 Building Code (NCC) regarding energy efficiency?

The industry (builders, architects, others) are having their say at the moment but I can’t see where the homeowners are being asked!

It is proposed to go from 6 stars to 7 stars, I am all for better buildings but not sure this is the best way!

Please consider;

  • Going from 6 to 7 stars will save your heat/cool costs $80 to $230 per year
  • Reduce your Greenhouse Gas Emissions around 300 to 900kg per year
  • Cost 2.5% to 12.6% ($16,000 to $87,000)
  • Help Australia towards its Zero Carbon goal
  • Help save the planet if we are truly in a Climate Code Red situation
  • Doesn’t take into account the greening of the electrical supply grid which is happening now
  • Doesn’t take into account the increased embodied energy for the additional materials & products to achieve 7 stars
  • Other ideas, a blower door test ($500) would improve the existing requirements as there would be an actual test at completion rather than a bit of paper ensuring people installed things correctly, not build leaky buildings
  • If you added 1kW of PV (solar panels) it would reduce you consumption by 1,400 kW per year and only cost $300-$500 (assuming you were ging to have a system installed already)
  • Or should we prioritise reduce consumption of kW/GGE over cost? (will take 150 to 380 years to recoup the building cost of 7 stars with a kW price of $0.24) please note houses last around 50 to 100 years before demolition.

Please let me know your opinion or thoughts!!!

Permeable Building Wrap, NCC 2019, Condensation Management

Are you a house builder or energy rater?

BCA 2019 Volume Two (Class 1 houses), Clause 3.8.7.2 requires that if a pliable building membrane is installed (building wall wrap) it must be a vapour permeable membrane for Climate Zones 6, 7 & 8.

In Sydney imagine a line from Berowra, Hornsby, Castle Hill, Parramatta, Milperra, Lucas Heights & Heathcote to the west of this is Climate Zone 6, wall wraps must be permeable to reduce risk of condensation occurring.

  • Standard sarking is not permeable at  0.01 μg/N.s (poor)
  • AS 4200.1 minimum requirement 0.14 μg/N.s (low permeability)
  • James Hardie Wall Wrap 2.2 μg/N.s (very good)
  • Proctor RW 4.5 μg/N.s (excellent)

James Hardie wall wrap is also a reflective barrier which suits a temperate climate like Sydney.

Proctor RW is not reflective which would be a better choice in a colder climate like Blue Mountains or Southern Highlands.