42: How do you calculate building R value for free?

Design Navigator is a great, online resource for calculating the thermal performance of your house plan. I spoke with developer, Albrecht Stoecklein about why he created it and a great new feature he's just added.

References

• http://www.designnavigator.co.nz/index.html
• http://www.energywise.govt.nz/resource/design-sun
• http://www.ecotect.co.nz/PDF/eecapsfs.pdf
• http://www.waitakere.govt.nz/abtcit/ec/bldsus/pdf/energy/designsun.pdf