A guideline to retrofitting insulation

When it comes to retrofitting insulation, it pays to do your homework before you start working on your home.  The costs involved in getting insulation retrofitted into an existing property will vary greatly depending on a number of factors, as listed below.


Competition in the main centers is always likely to be greater therefore it will be possible to negotiate better deals.  Furthermore, the supplier companies will likely have the stock and operations in the main centers, which means the more regionally isolated your property is the more likely you will have to pay a ‘travel/freight’ premium.

Type of Insulation

Minimum R-Values (thermal resistance) for retrofitting homes in NZ
Zone 1 and 2Zone 3
CeilingR 2.9CeilingR 3.3
UnderfloorR 1.3UnderfloorR 1.3

The most common products used in retrofitting homes is glasswool in the ceiling and polyester underfloor.

Quality of Existing Insulation

Many properties may already have some insulation, but will often not meet the minimum requirements.  However, if the existing product is of good quality, you may only need a simple ‘top-up’ product which will be a lot more affordable than replacing the lot.


Sometimes factors like access may add costs, such as ensuring the manholes are big enough to get products into the underfloor or ceiling.  In some cases, getting to hard to reach places may incur an extra cost.

Pricing example for Retrofitting a 100m2 residential property

The following is a typical cost of retrofitting insulation in a residential property in Auckland.  This example assumes there is no existing insulation and that there is good access to ceiling and underfloor.

  • Floor area of house (liveable area, does not include garage)= 100m2.
  • Suspended timber subfloor.
  • Minimum standards only for insulation to meet requirements. Ceiling = R2.9Glasswool, underfloor = R1.5 Polyester.

Supply and Install cost ceiling Supply and install cost underfloor

  • Supply and install cost ceiling – $1,330.00
  • Supply and install cost underfloor – $1,450.00
  • Plus GST – $417.00
  • Total (Including GST) – $3,197.00

Funding options

We have a range of funding options available to you, including Finance Now, adding to your mortgage, or using a council funding scheme (if available in your area).  You will not pay any more than normal prices to use these schemes. More information is available at: www.premierinsulation.co.nz/finance

Discounts and other promotions

Do your homework on pricing before you make a final decision.  There are companies that offer customers big discounts if they sign up immediately, but often are just inflating their ‘trade’ price and then offering a ‘discount’ as an incentive to buy now.  Discounted prices offered may be no better than the standard market prices and can sometimes be higher.  Get a competitive price from Premier Insulation to compare against. We’ll suggest the best product options for your property and will give you a clear price to do the job.  Premier can also offer funding options to help you get the insulation installed now and pay later.