How insulation works

How does insulation work? 

A basic law of physics is hot things get colder, cold things get hotter and they eventually end up the same temperature. In winter, the heat inside an un-insulated home will escape outside and in summer, the heat outside will flow inside.

  • Heat can pass through any material but some materials are more resistant to heat flow than others.
  • Good resistance equals good insulation.
  • Insulation is a barrier to heat flow. It keeps the heat in when it’s cold and the heat out when it’s hot
  • The higher the insulation R-value (which is the measure of how much resistance to heat flow the insulation has) the better the insulation works.

House heat loss percentages

An un-insulated home uses up to 30% more energy to heat than one with correctly installed insulation. This makes insulation one of the smartest investments you can make in your home*


Why is insulation important?

More than 500,000 homes in New Zealand are estimated to have inadequate insulation so they are often cold, damp and expensive to run. Homeowners attempt to fix these problems with heat pumps, dehumidifiers and other devices. The best solution is one that first addresses the fundamental problem of the heat escaping.

Insulating your home is the most effective measure you can take to keep your home comfortable year round and save money on energy bills.

A well-insulated home is warmer, healthier and more pleasant for you and your family. According to a Wellington School of Medicine survey**Families living in insulated homes had fewer sick days and doctor visits.

An inadequately insulated house can negatively affect your health. Indoor temperatures below 16°C increase the risk of respiratory disease.  The World Health Organisation recommends temperatures of at least 18°C and minimum 22°C in homes with young children. 

*Fung.J.'SR 230- Higher than NZBC Thermal Insulation in New Housing Cost-Benefit Analysis' BRANZ Report 2010.  

** Howden-Chapman, P. et al. "Effect of insulating existing houses on health inequality: cluster randomised study in the community" British Medical Journal, 2007, p.334:460


Why is correct installation important?

Correctly installed insulation is a key factor in how well insulation works. Insulation's benefits can be decreased by a poor insulation job - gaps,tucks and folds decrease your insulation's effectiveness.

Using a professional installer can make all the difference. 

View our tips on correct installation