What is Insulation R rating - Understanding Insulation R values and what they mean for you.
- Jan 19
- 6 min read
You've googled what is insulation R rating, or what do insulation r values mean. You've likely already sifted through articles that quote the science of it (R value measures how well a material prevents heat moving through it), or companies explaining the higher the R rating the better.
And if you want the science of it, you're in luck! We have an article on the specs and science of it coming soon.
But today you want context!
At the end of the day, the thermal mass and heat flow graphs don't mean much to the average homeowner, your builder or insulator is just going to talk jargon over your head anyways. But you want to be armed not with trivia and specification sheets, but with understanding of the insulation you're having installed.
So the question isn't "What are insulation R ratings" the question is "What do insulation R ratings mean for YOU!"
The Insulation R Rating Meaning for YOU!
So let's set some guideposts, if you will. These will help set your expectations on different R values of insulation and how they impact your comfort and home.
Then let's use these guideposts, add some case studies and examples, as well as anecdotes and our experienced opinion to give you the understanding to make an informed decision.
Insulation R Value Guide Posts
Healthy Homes Standard Insulation R Values
The best place to start is with the question: What's our minimum R rating?
Healthy Homes Standards are the minimum standards that insulation in your existing home needs to meet to be considered safe and healthy enough for a third party to rent and live in it. This isn't about comfort yet, this is the least you need for local authorities to consider your home safe and healthy as an existing home.
(We will get to new build after!)
New Zealand is set up in insulation climate zones, that changes what these minimum standards to be safe and healthy are. (As you would expect, the wild and wet west coast of the South Island is a different climate zone to the far north of the North Island.)
But here in Auckland (Climate Zone 1) our Healthy Homes Standards for insulation R values you need to be aware of are:
HHS Underfloor Insulation R Value: R1.3 Minimum.
HHS Ceiling Insulation R Value: R2.9 Minimum.
H1 New Build Insulation Requirements
So now we have covered the minimum for existing homes, what about building a new home today? What are your new build insulation R values?
Again, these are the bare minimum for a house to get consent to be built. In essence these minimums are saying "anything less than this is not safe and healthy for a modern home with modern standards."
They're calling you cavemen, cowboys on the frontier, maybe like that guy out of Hunt for the Wilderpeople, if your house doesn't meet these standards. (Not to mention you'd be in big trouble too...)
The H1 Insulation standards for new build insulation R values are (currently) in Auckland:
H1 Underfloor Insulation R Value: R2.5 Minimum. (Not including Slab on Ground: R1.5)
H1 Ceiling Insulation R Value: R6.6 Minimum.
H1 Wall Insulation R Value: R2.0 Minimum.
Choosing your Insulation R Rating
Get the R Value right the first time!
Right off the batt we need to make something clear: when you work with us at Island Insulation most of the time the install costs are exactly the same no matter the R value of the specific product.
That means it costs the same to install 1m2 of R1.4 EXPOL as it does to install 1m2 of R3.1 EXPOL. You only save money on the material, making it important to "do it once and do it right" when it comes to insulating, as it will cost more to add more later.
Scenario One: You install one layer of the lowest R value | Scenario Two: You install one layer of the highest R value | Scenario Three: You have to upgrade from scenario 1 because it wasn't good enough the first time! | |
MATERIAL | EXPOL | EXPOL | EXPOL |
R Value | R1.4 | R3.1 | R1.4 + R1.8 =~R3.1 |
Depth of Insulation | 60mm | 100mm | 120mm |
Price of Product | $16/m2 | $42/m2 | $16 + $22/m2 = $38/m2 |
Price of Install | $6.50/m2 | $6.50/m2 | $6.50 + $6.50 = $13/m2 |
TOTAL | $22.50/m2 | $48.50/m2 | $51/m2 + |
Don't be left wishing you had added just a couple extra points to your insulations R value!
Go above your minimum R values!
The next thing to consider is this: the minimums are MINIMUMS. They are not the goal, they are the least you can do and get away with it.
Reaching the minimums and saying that'll do is like saying "the ferry/bus/plane leaves at 5:00pm, I'll get there for 4:59pm, it's within the tolerance!"
Or better yet, "My blood pressure is 1 point away from giving me a heart attack, I'll just keep it right here in the sweet spot"
Most people agree, hitting the minimum you can get away with is often not the best call!
Sometimes though its all we can do, and in those circumstances we have to make do. But if you can help it, go for more!
Okay, let's breakdown how to go through choosing your insulation R value!
Choosing Insulation R Value Example: Wall Insulation R Rating
First question: What is the minimum wall insulation r rating we can have?
Answer: R2.0 (H1 Building Standards.)
Second question: How much more R rating can I get for a reasonable price increase?
Answer: Island Insulation Price sheet LINK
R1.8 - $12.74/m2; 90mm
R2.2 - $7.50/m2; 90mm
R2.4 - $9.75/m2; 90mm
R2.6 - 13.75/m2; 90mm
R2.8 - $19.75/m2 90mm
Well that's clear as day, there would be no point in going for anything less than R2.4 as its only a couple dollars more than R2.2. And R1.8 is out of the question!
The upgrade from R2.2 to R2.4 is only $2.25 difference, for an average home that might only be a total build increase of ~$300. Well worth it!
Boosting from R2.2 to R2.6 is $6.25 difference, that would be an average of maybe a $800 total build cost increase.
The upgrade in comfort may be well worth it for you!
Third Question: What will these R Value increases really change to my daily life?
Answer: Quality of install will change a lot more than small R value increases, but once you have quality installers, a good insulation plan, and high R value insulation, those changes will add up.
I would highly recommend you talk to our team and having a demonstration of the different product options and R values. Look through our portfolio for inspiration!
Ask your friends what they had installed, and how its going for them. Perhaps take a look. Feel the difference between the main house and the sleepout, or the garage.
A lot of our clients find the biggest difference is made by product type as well, at least in their opinion and we would have to agree! Look into our insulation brands and materials:
We hope to have full live demonstrations live soon! We can only do that with your help! When you use Island Insulation for your build or retrofit install, you choose people who care about increasing education and innovation in the industry.
Interior Walls and Mid-floor Insulation
One last point before we finish up for today. Mid-floor and interior walls are often neglected. Perhaps the lowest R value or no insulation at all is installed. This is a massive mistake! And very hard to fix later!
Mid-floor insulation helps to stop your upstairs becoming an oven while your downstairs sits in endless cold. Blasting the heaters in the downstairs bedroom all winter doesn't help much when there is only a thin sheet of wood and gib between your bedroom and the entire upstairs.
Not to mention sound! Acoustics are just as important when considering insulation. Trying to sleep while the party carries on upstairs? You don't want to hear every word and footstep, and you will without mid-floor insulation!
Interior wall insulation also helps isolate problem areas and living areas.
You want more than gib between you cooking dinner, the steamy shower, the laundry, the kids asleep in the bedroom. You will also save power if you can isolate the rooms you're heating and cooling.
Interior wall insulation and mid floor insulation goes hand in hand with a good HVAC system and plan. Together we can make your house feel like a home all year round!
Conclusion
I hope this has given you some food for thought as you go over your insulation plans for your next project!
Ofcourse, this is no substitute for a good consultation with one of our team, so reach out!
We're always happy to have a chat about your insulation goals and what will best get you there!
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