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Ceiling (Roof) Insulation


Why buy ceiling insulation?

  • Save up to 45% on heating and cooling
  • Reduce greenhouse gas emissions
  • Rely less on heating and cooling systems
  • Make your home more comfortable

Achieve the R-value you want

Installing ceiling insulation is a perfect DIY project for your home. Just make sure you:

  • Don’t compress the insulation, and
  • Don’t leave gaps between segments as this will make it difficult to achieve the R-value you want.

Quality ceiling insulation at great prices!

Pricewise Insulation sells only the best residential roof insulation brands including Knauf Earthwool and Autex Greenstuf. Our reputation is built on quality, customer service and competitive pricing.

Buy Ceiling Insulation Online

Residential roof insulation is mandatory in all rental properties, and today it would be almost unthinkable to build or renovate a home in New Zealand without installing proper ceiling insulation. The financial (cost saving) benefits of ceiling insulation are significant, and can be summarised as follows:

1 – Ceiling insulation greatly reduces heat transfer through the ceiling, helping to keep your home cooler in summer and warmer in winter.

2 – As a result of the above, ceiling insulation will typically result in substantial savings on your energy bills.

It is estimated that in an average uninsulated home, the ceiling is responsible for up to 35% of all heat losses in winter and heat gain in summer. Windows, walls, underfloor areas and air-leakage from cracks and gaps in the various parts of the building account for the remaining thermal inefficiencies.

Different Types of Ceiling Insulation

Here at Pricewise Insulation we sell all the best brands of ceiling insulation from the most reputable manufactures and importers.  Below is an overview of the ceiling insulation brands we sell, the materials they are made from, and the R-Value* range available.

ManufacturerBrand nameMade fromTypeR-Value Range
Knauf InsulationEarthwoolLow-itch GlasswoolSegmentsR3.2 - R6.3
Autex IndustriesGreenStufPolyesterSegmentsR2.9 - R3.4
Tasman InsulationPink BattsGlasswoolSegmentsR2.2 - R3.6
CSR BradfordBradford GoldGlasswoolSegmentsR2.7 - R6.0

*Note: The R-Value is based on a single layer of ceiling insulation being installed. Higher R-values can be easily achieved by installing a second layer of ceiling insulation.

Knauf, Autex and Tasman also manufacture ceiling insulation in rolls, which can also be quicker to install if there is sufficient room to move around, and not too many obstacles such as pipes and wiring.

ManufacturerBrand nameMade fromTypeR-Value Range
Knauf InsulationEarthwoolLow-itch GlasswoolRollsR1.8 - R3.6
Autex IndustriesGreenStufPolyesterRollsR1.0 - R3.6
Tasman InsulationPink BattsGlasswoolRollsR2.9 - R3.3

How does ceiling insulation work?

Most materials used in the construction of homes are inherently poor insulators. Timber, bricks, concrete and steel – when exposed to higher or lower temperatures, each of these materials are quick to transfer heat and cold. When the temperature outside is significantly more or less than it is indoors, heat gain and loss will occur. The greater the temperature difference, the higher the heat gain or loss, and the more energy will be required to maintain the desired indoor temperature.

Bulk ceiling insulation works by slowing down the transfer of heat and cold. The secret behind all bulk thermal ceiling insulation is the millions of tiny air pockets contained within the insulating material. These air pockets make the insulating material a poor heat conductor, or if you like, an effective insulator. This is also why a thicker piece of bulk ceiling insulation will generally have a higher R-Value than a thinner one.

“Materials with a high thermal conductivity are inherently poor insulators.”

What is the difference between wall and ceiling insulation?

Ceiling insulation works in a very similar way to wall insulation, and is typically made from the same materials, although the density may be slightly different. Residential ceiling insulation is typically a higher R-Value, and since most ceilings have more than enough space for any thickness of insulation, the thickness of the ceiling insulation segments or rolls is of little concern. This is in contrast to insulation for walls, which needs to be able to fit within the internal wall cavities.

Can you put new insulation over old?

In some circumstances, it may be appropriate to install a new layer of insulation on top of an old layer, and this may also be the most economical option. The following overview is tended as a rough guide only:

Condition of existing insulationR-value of existing insulationRecommended options
No insulationN/AInstall new insulation
Good condition, installed evenlyMore than requiredNo extra ceiling insulation required
Good condition, installed evenlyLess than optimalTop up with new insulation
Deteriorated, unevenly installedInsufficientReplace with new insulation
Water damagedInsufficient/no insulating valueRemove immediately* and replace

*A note on water damaged ceiling insulation

If the insulation in your ceiling has ever become wet (for example due to being stored out in the rain, standing in a flooded garage, or due to a leaking roof) then the wet insulation should be removed entirely and replaced with new, dry insulation. Never attempt to try to “dry out” insulation segments or rolls which have suffered serious water damaged, this is very difficult to achieve, and the risk of some portion of the insulation remaining wet is very high. There are 3 important reasons why wet insulation should never be used, and why it should also not be allowed to remain in your roof.

1 – Wet insulation has practically no R-Value. Bulk thermal insulation depends entirely on the air pockets contained inside the insulation segments being dry and open. Once these air pockets become saturated with water, the material becomes practically useless for all insulating purposes.

2 – Damage to building materials. Wet insulation lying down on the ceiling will, over time, cause damage to the underlying ceiling boards.

3 – Mould and mildew.A piece of insulation which has become very wet may remain damp for weeks or even months into the future. This provides a perfect environment for mould and mildew to flouring. Mould is known to cause a host of health problems, and once established can be difficult to properly eradicate, especially if it established itself in hard to access areas.

How do you tell if your house is well insulated?

The first thing you want to check is the ceiling, and try to estimate the performance R-Value of any insulation which is currently installed. If the existing insulation was of a high quality and was installed properly the first time, and if the insulation hasn’t been damaged or tampered with in any way, you can assume that it’s performing very close to its original specified R-Value. If it’s not entirely clear exactly which roof insulation product was installed in your ceiling all those years ago, then the best you can do without specialist tools, is to measure the approximate thickness of the insulation, and make a very rough estimate. The below table assumes the existing ceiling insulation is in a reasonably good condition:

Thickness of old/existing insulationR-Value Range Estimate
100mmBetween R1.0 and R2.0
150mmBetween R2.0 and R3.0
200mmBetween R3.0 and R3.5

Depending on which climate zone your house is in, as a minimum you need between an R2.9 and R3.3 in the ceiling. However, if you want an extra well insulated house, we strongly recommend that you consider upgrading to a higher-than-minimum R-Value in the ceiling, as this will deliver superior performance and save you even more energy, for the life of your home!

How often should ceiling insulation be replaced?

All the insulation Pricewise Insulation sells here in New Zealand comes with a minimum 50 year or “lifetime” warranty, applicable to the home where it is installed. As such, ceiling insulation can be considered a one-off investment, and the sooner you get in installed, the earlier you will reap the excellent benefits. Ceiling insulation which becomes damaged e.g. due to flooding, should be replaced as soon as possible.

Does adding insulation increase the value of your home?

Ceiling insulation increases the energy efficiency of the home, and if you’re selling your home, most potential buyers will be pleased to discover that this has already been taken care of. Of course, as with any “home improvement”, it’s not possible to predict exactly how much (more) a buyer might be willing to pay due with regards to the house being properly insulated. However if the house it not adequately insulated, you might find a prospective buyer using this as a bargaining chip to push down the price.

Pricewise Insulation recommends that first and foremost you consider ceiling insulation as an investment for you and your family’s future comfort and energy savings.

Installing Ceiling Insulation

The process for installing ceiling insulation in an existing home (i.e. retrofitting) is different to installing it in a new building, or in a house where the ceiling is exposed due to being renovated.

The below videos include lots of handy tips and advice for installing ceiling insulation in each of these two scenarios.

Installing Ceiling Insulation: Pink Batts, Retrofit

Installing Ceiling Insulation: Earthwool, New Build

Have any more questions about ceiling insulation?

If you need further assistance or advice prior to placing an online order for ceiling insulation, don’t hesitate to give our friendly team a call on 0800 697 742