A question we get asked quite often is, "Can you have too much ceiling insulation".  My answer is changing as I see more examples of the impact of our warming climate and changing international standards.

At The Insulation Warehouse, we don't like over selling, or, selling something that clients don't need.  The NZ building code has a minimum requirement of R2.9 for ceiling insulation so that has been our starting point and we frequently install R3.6 and upgrade to R5.0 from time to time. (The R number is a thermal resistance rating and the higher the number the better the insulation)

NZ's government via MBIE have embarked on a review of the NZ Building Code insulation requirements.  Read more about this here. In this review they are looking for feedback on 3 scenarios:

Option 1. Halfway to international standards – Increase the minimum insulation to a level that is approximately half of that from other parts of the world with similar climates. This represents a modest increase in insulation levels versus the current minimum settings and would still leave New Zealand considerably behind other countries. This would have the least amount of upfront construction costs. ›

Option 2. Comparable to international standards – Increase the minimum insulation to a level that is comparable with other parts of the world with similar climates. This represent a moderate level of change versus the current requirements and would significantly reduce energy demands for heating and cooling.

Option 3. Going further than international standards – This is the greatest level of increase proposed. This would put New Zealand's minimum insulation levels ahead of other parts of the world with similar climates. It would have the greatest impact on current construction requirements and the biggest reductions in energy use. 

Our view is that there will be a change to the Building Code and this will likely be option 2 (just our view).  This could see the minimum ceiling insulation change from R2.9 to somewhere around R5.0, a very meaningful shift.

In October 2020 we shared this research article on our Facebook page.  It make a compelling case that our new homes are being overwhelmed in the summer with uncomfortable heat levels which, in my opinion, is a result of insufficient insulation levels and insufficient window standards. 

There are currently ceiling insulations available up to R7.0. 

Our conclusion is that there is merit in going well beyond the current minimum requirement of the NZ Building code.  This can be achieved using a single layer of insulation, or, by installing 2 layers of insulation to achieve the optimum ceiling insulation result.  Have a look at this page on our website to see what we mean.  

If you are interested in discussing options of adding more insulation in your ceiling to create summer and winter comfort please call our team 09 6368409 or email support@tiwl.co.nz

• insulation
• 23 April