Wall Insulation

Your choices about wall insulation will have a big impact on your home's long-term comfort in summer and winter. Get free advice about the best options for your new home or renovation.

The Benefits of Wall Insulation

Adequate, quality wall insulation is a critical component in the thermal envelope that is your home. Many of New Zealand's cold, damp homes are due to little or no insulation in the ceilings, floors and walls. Up to 25% of your heat can be lost through the walls in an uninsulated home.

As a building component it's hard to retrospectively add or upgrade your wall insulation so when building or renovating take full advantage of the opportunity to insulate your walls well.

Smart Energy Solutions can give you free advice on the best wall insulation for your new home or renovation and we have experienced installation teams nationwide to professionally install your insulation in walls, ceilings and floors.

New Home Wall Insulation

Wall insulation is mandatory in all new homes and yet, hidden behind wall board, it doesn't always get full consideration.  Your choices about insulation for your walls will have a big impact on your home's long-term comfort in summer and winter.

Some of the questions that need to be asked include:

  1. Should I use fibreglass or polyester insulation?
  2. Is the minimum building code R-value enough?
  3. Should I add acoustic insulation to key internal walls?
  4. What happens if insulation in the wall settles over time?

Our new home representatives can assist with free information on wall, ceiling and floor insulation as well as other energy solutions like LED lights, ducted and split system heat pumps, ventilation, heat pump hot water and more.  Read more about New Home Energy Efficiency.

Smart Energy Solutions has professional insulation installers that can install fibreglass and polyester insulation in new homes as well as ceiling and underfloor insulation.

If you're a builder or building, contact Smart Energy Solutions to improve the energy efficiency of your next home. Call Us on 080 888 766 or email your house plans to [email protected]

Retrofitting Wall Insulation Info

Up to 25% of heat can be lost through the walls of an uninsulated home so naturally retrofit wall insulation is of interest to many home-owners.

Retrofitting wall insulation to an existing home is more complicated due to the obvious barrier of your wall board. We encourage you to ensure you've addressed the solutions that are easier to access first to get best bang for your buck:

  • Ceiling insulation - 35% of heat is lost through an uninsulated ceiling. if you have a roof space it's the first place to start.
  • Underfloor insulation & fit ground moisture barrier where possible. 10-15% of heat is lost through uninsulated floors.
  • Thermal well-fitted curtains

Once your ceilings and floors are insulated the next biggest heat loss is through windows and walls.

Options for Retrofitting Wall Insulation

We have summarised the three main options for retrofitting wall insulation into existing homes below.  All these options for wall insulation retrofitting require a building consent due to the complexity of the work and the potential ramifications on the overall building envelope.  Smart Energy Solutions does not retrofit wall insulation unless it is a major consented renovation where you are removing or replacing the wall board.  

Foam wall insulation:

This process involves drilling holes into the external (or sometimes internal) cladding of your home and injecting a foam - Urea Formaldehyde Foam Insulation (UFFI) into each individual wall cavity between the joists and nogs. 

The Building Research Association of NZ (BRANZ) has expressed concerns about shrinkage, cracking, missed sections and the installed thermal performance of foam wall insulation (refer Build Magazine article). There are also some concerns and uncertainty regarding the effect of the foam encasing electrical wiring.

Blown fibre wall insulation:

This process again requires multiple holes to be drilled into your wall to blow loose fibre insulation into each small wall cavity.  The challenge with blown fibre is that it has a tendency to settle over time creating significant gaps in the wall insulation that heat readily flows through.  For this reason and again the need to drill holes into each joist/nog cavity Smart Energy Solutions does not offer blown fibre wall insulation.

Removing wall-board to fit insulation sections:

The best, and slightly more expensive option, is to remove the wall board and fit building paper then sections of wall insulation to fully fill the wall cavity.  EECA has created a handy video guide to retro-fitting insulation easily including the tip to leave a strip top and bottom to avoid the need to replace cornices or skirting boards.

Alternatives to Retrofit Wall Insulation

Thermal curtains: Heat will flow through the weakest part of your wall system which will always be the windows if you haven't got effective thermal curtains. Make sure they are well fitted, touch the floor to limit air flow.

Ventilation: If your issue is damp or mould then effective ventilation (either natural or mechanical) may have a greater effect than wall insulation.  Read more about ventilation.

Wall Covering: For an existing masonry/concrete block wall, you can add Mammoth wall covering to improve the situation.  Mammoth wall covering is an acoustic solution with a low R-Value but for a concrete block wall it can reduce the radiant cold effect and improve the comfort of rooms.  It is available in a choice of colours and is glued to the concrete wall.