Existing Homes - typical Questions


Retrofit insulation is installing insulation into existing homes that have little or no insulation. New insulation is typically installed into the ceiling and underfloor where accessible and there are even options to blow insulation into existing walls. Insulation is one of the most cost-effective ways to reduce energy waste and improve the comfort of your home.

  • Energy flows like water, any gap is like having a hole in a bucket.
  • The best way to ensure a warm, dry energy-efficient home is to insulate all accessible areas of the thermal envelope.

The thermal envelope consists of three main elements; your ceiling, underfloor and your external walls. The “Thermal Envelope” is the outside layer between the inside of your house and the outside. A better insulated thermal envelope creates a warmer, drier and healthier internal environment and a more energy efficient home.

Thermal bridges are weak points in the thermal envelope. Structural timber, while an important requirement for your building, represents an area of weaker thermal performance. Depending on the extent of thermal bridging, your insulation could be performing significantly worse than the R-Value on the label. Our teams are trained in ways to reduce the effects of thermal bridging, book a free assessment to discuss options.

In most circumstances, we can complete the installation at your home within one day.

Yes, as our teams will be working around existing wiring and electrical devices we require the power to be turned off for the duration of our install activity.
Generally, the power does not need to be turned off for new build construction.

We have robust quality control requirements which include a thorough internal audit and training system. All of our installers are trained to install insulation to meet the requirements of NZS4246:2016

We offer various options to suit your individual circumstances:

  • Internet online banking
  • Visa and MasterCard accepted – No fees for credit cards
  • PayPal
  • Q-Card payments accepted for Q-Card holders
  • Squirrel homeowner loans up to $70,000 find out more.
  • Also, most major trading banks offer special lending options for home improvements and energy efficiency improvements for homeowners.
  1. Upon receiving your enquiry we will book a free assessment with one of our expert insulation assessors. 
  2. After visiting and assessing your home, our assessor will provide you with a quote, including our recommendations and any options you have indicated you would like to review. 
  3. Upon your acceptance of our quote, our highly trained install team will will complete the install work (usually completed within a day!) 
  4. As part of our quality control processes, we may ask to revisit your property to inspect the installation work. 
  5. Upon completion of our quality processes you will be invoiced for the works completed.
  • An R-Value is a measure of the insulation’s ability to resist the transfer of energy (heat).
  • Put simply, higher R-Value contributes to a warmer, drier, healthier and more energy-efficient home.
  • Enstall is a part of the EECA Warmer Kiwi Homes program. This program provides a subsidy for the installation of ceiling and underfloor insulation into eligible houses, as well as a Ground Vapour Barrier where applicable. Once your insulation has been installed, you could be eligible for a subsidy for a heating device as well.
  • We have a team of highly trained assessors who are able to complete a whole-of-house inspection. As a result, we can determine whether your property already meets the standards. Where it does not we can provide you with a recommendation or, for specific areas, a quote to bring the property up to standard. Our assessment is compiled into a professional report for your record keeping.
  • For new build construction we can offer a Healthy Homes Standards report. This is based on the building consent plans to help you verify that your buildings will meet the requirements of a rental property.

Ceiling Insulation Q's


  • We offer a wide range of different types of ceiling insulation, made most commonly from polyester, glasswool or sheepswool fibres.
  • These insulation products can come in a variety of forms including segments, rolls or as a loose blow-in product.
  • All products we offer are compliant with the NZ Building Code.
  • Depending on the construction of your home, different products may be best to provide your optimal outcome.
  • Book a free assessment with one of our expert home assessors for our recommendations, or send us your building consent plans for a quote
  • Light fittings have a range of different ratings, some light fittings are safe to cover with insulation while others require safety clearances.
  • If your home has light fittings which cannot be covered, we can offer a quote for replacement LED fittings to reduce the number of gaps required in your insulation so you get the most out of your new insulation.
NZS 4246 Non-Rated Light Clearances
Enstall NZS 4246 CA Light Clearances
Enstall NZS 4246 IC Light Clearances

Underfloor


  • We offer a range of different types of underfloor insulation, made most commonly from polyester or glasswool fibres.
  • These insulation products can come in a variety of forms including segments, rolls or with “windwash” barrier technology. All products we offer are compliant with the NZ Building Code.
  • Depending on the construction of your home, different products may be best to provide your optimal outcome.
  • Book a free assessment with one of our expert home assessors for our recommendations, or send us your building consent plans for a quote.
  • Foil insulation provides little to no insulation benefits and represents a health and safety hazard to any person entering an underfloor area.
  • Our recommendation when foil is present is to remove and replace it with a new NZ Building Code compliant insulation.

NZS4246 requires all polystyrene to be physically separated from the wiring. The polystyrene can have a reaction with the coating on the wires, causing both the polystyrene and the protective coating of the wire to degrade.

In extreme circumstances, this can lead to a health and safety hazard with the wiring becoming exposed, or severe damage to the polystyrene reducing its effectiveness.

As a result, Enstall recommends the removal of existing polystyrene and replacing it with a modern, safer alternative.

Ground Moisture (Vapour) Barriers (GVB)


  • Moisture in the ground under your house can rise up and then condense on the underside of your floor. 
  • GVB is designed to inhibit the transfer of moisture from the ground and to the underside of the house.
  • Moisture/water can be absorbed by floors constructed from wood.
  • The moisture can, over time migrate into the house and may also cause structural deterioration of the timber.
  • High-grade black polythene with a minimum thickness of 250μm (0.25mm) installed on top of the ground in your underfloor area.
  • Ground Vapour Barrier when installed in accordance with NZS 4246, together with normal maintenance, will continue to satisfy installation requirements for not less than 5 years.
  • Ground Vapour Barrier may not be suitable for all homes; rocky underfloors, properties with access restrictions, or properties prone to flooding are examples when a GVB may be unsuitable.
  • For more information or advice, book a free assessment with one of our expert assessors.

External Wall Insulation for Existing Homes


Yes!

Enstall operates a BRANZ CodeMark approved system for installing blow-in insulation into external walls of existing homes.

  • Not all houses should have blow-in wall insulation installed.
  • Our expert assessors can ascertain whether your property is suitable for this application.
  • Not all houses should have blow-in wall insulation installed.
  • Our expert assessors can ascertain whether your property is suitable for this application.
  • Yes, there are some risks that need to be managed associated with blow-in external wall insulation.
  • The best way to find out whether your property is suitable is to book a free assessment with one of our trained assessors.
  • We will provide you with the result of our assessment and our recommendations for the best way to insulate your exterior walls.

CodeMark is a voluntary product certification scheme that provides an easily understood and robust way to show a building product or system meets the requirements of the New Zealand Building Code. A product can be a building or construction method, building design or a building material.

It also provides an advantage as certified products are deemed to comply with the Building Code, are listed on our public Register and can use the CodeMark brand on advertising relating to the product.  Councils must accept Codemarks if their use and application is in accordance with the definitions of the Codemark.