Frequently Asked Questions

How do you know if you have insulation in the wall already?
You can pop a power socket of an external wall, look in with a torch and even poke something in (a bamboo stick works very well) and feel the insulation if there is any.  When we proceed to installation, we are always finding areas on houses that have random insulation, if we find these areas we just reduce the cost to you.  If you want to check yourself, please use a non-metal kebab stick, or just call us for an obligation free inspection.


How do you ensure you fill the cavity completely (obviously pointless if there are any gaps)?
The unique nature of ThermoWall being a liquid foam with the consistency of shaving cream when injected, allows it to flow around any obstacles including water pipes and wiring without getting caught up, filling the entire cavity. Your licensed ThermoWall installer is a professional and approaches every job in a tradesman like manner, by applying a combination of techniques including; timing the cavity fill, methodical placement of the insertion holes, and back-pressure out the insertion hole, he is able to ensure a cavity is fill.
The foam will generally get a 96-98% full wall when dry.  As it dries it will shrink a little (about 2-4%, hence 96-98%), but this is how it will stay for the foreseeable future.  When any other form of insulation is fitted i.e. fiberglass or wool, they normally only get filled at about 85 - 90% efficiency due to the type of construction being imperial over metric, creating a difference in cavity size.  The foam, unlike batts, will also fill into gaps and cracks which will help reduce air infiltration (thermal bridging).
If you watch the way we do the installation, and understand how most houses are constructed, it’s pretty hard to miss areas.  
Please remember we get full code compliance for this so we have to meet certain requirements.  Our installers are good at what they do, it’s a very specialized job.  Our installers are fully aware of the quality controls we have in-place and training is given to ensure that our product is installed are per the manufactures requirements and in conjunction with the New Zealand building code.


Who are the tradies? Are they employees of Heatsavers or do Heatsavers contract tradies?
This is not the type of job you could employ a sub-contractor for as we have to take responsibility for the site, we may not need to be licensed building practitioners, but we still understand our regulatory and NZ Building Code requirements.



He says "do it from the inside so you don’t break the water seal of the outer house?
We can insulate from either the inside or the outside, it's really up to you.
We understand the logic behind this comment, however, the main reason we get full NZ Building Code compliance is that our processes have been shown to be very robust (in combination with good maintenance obviously), and we have to guarantee we leave your house water tight.  Under s112 of the building act " you must not reduce a walls function , it must remain the same, or improve"  so going by that code we make sure your walls are water tight,  however if you already have water tight issues we would pick them up before with our required pre inspection.   On this note, as the product does shrink a small amount, this actually helps reduce the chance for moisture bridging that could occur if you where to get a leak in your cladding.  We can actually foam houses with no building paper and have no issues will moisture ingress.  It is worth adding that a 60 year old building paper may not be the best water deterrent anyway, 
In service tests on houses have shown that even 30 years on with good maintenance your home will continue to function the way in is supposed to .


Is ThermoWall suitable for ceiling insulation?

No. The material has been developed strictly to fill the enclosed space between inner lining and the outer cladding of exterior walls of buildings.



Can I have ThermoWall installed from the exterior on part of the house, and then some installation completed from the inside on the remainder of the house?

Yes. Your licensed ThermoWall Installer will work with you to suit your particular needs.



How frequently spaced are the injection holes?

This will depend on the age and/or construction of your house, and should be discussed at the time of quotation.



What happens to the electrical sockets on the inside of my wall when ThermoWall is pumped into it? Is this safe? What about the dampness?

As part of the HeatSavers process, and prior to injecting the ThermoWall, all powerpoints and light switch covers on the exterior walls are removed and packed with paper to prevent the ThermoWall entering the  electrics.  Once the ThermoWall injection is complete the paper is removed and the powerpoints and light switch covers are re-instated.

This process ensures that no ThermoWall or dampness enters the switch so it is completely safe.



Does ThermoWall corrode the plastic coating on the electrical wires inside the walls?

No. Unlike some plastics, ThermoWall will not react with plastic coated cabling.


Will installation disrupt my home?

There is very little disruption to the household during the ThermoWall process. Installation typically takes 1-2 days to complete. During the initial ThermoWall process powerpoints are unscrewed temporarily from all existing walls to prevent foam flowing into them. During the following 30 day curing period your ThermoWall Installer will advise you of certain ventilation procedures to follow, which normally includes keeping several windows ajar to assist with the ThermoWall drying process.


Will ThermoWall cause a fire hazard in the walls?

No. Even though there is intense heat, ThermoWall will not melt away. It will char, lose weight and volume but remain in place as foam.


What exactly is ThermoWall?

ThermoWall is a modified plastic foam containing millions of tiny air cells - very effective as insulation. It is non toxic, does not create a fire hazard, and is a breathable foam.


Will ThermoWall cause dampness?

ThermoWall tends to shed water rather than hold it and tends to resist water absorbtion. Our procedures ensure that moisture probs are installed in key areas to monitor the ThermoWall drying process, until all moisture dissipates. As well as this, your ThermoWall installer will discuss the requirement for adequate ventilation after ThermoWall is installed so that it will cure correctly. From then on ThermoWall will resist the reabsorption of liquid water.


Will ThermoWall cause a lingering problem of odour?

No. There will be no odour once the ThermoWall is cured. In a small number of cases there is a perceptible odour while the ThermoWall is curing. This can be avoided with adequate ventilation.


Will ThermoWall shrink and deteriorate with age, thereby losing its insulation properties?

No. Some initial shrinkage is normal but investigations show that ThermoWall maintains its physical and insulation properties. In fact, 15 and 20-year-old ThermoWall has been found equivalent in insulation performance to new ThermoWall.


Will ThermoWall create dry rot or other fungus infestation?

Definitely not - as long as the ThermoWall can dry in reasonable time. Extensive field investigations have determined that ThermoWall does not contribute to the development of fungus. Houses of over 200 years old were included in the investigations.


I've read online about wardrobes and cupboards filling up with ThermoWall. How do you stop this from happening?

ThermoWall has pre-installation checking procedures. We ask the home owner if they know of any areas within their home that the ThermoWall may be able to enter (other than our injection holes!). We also investigate every likely place that a potential mishap may occur, but generally this never happens.

The common areas that ThermoWall may leak is behind benches, cupboards and baths in spec built houses where wall lining have not been installed.


It is more important to install double glazing than insulate your walls?

FALSE  Windows comprise some 15 to 25% of the wall area of an average New Zealand older home.  When we compare the cost of  double glazing the window area (15-25%), versus the cost of installing ThermoWall into a much larger area (approx 75-85%) it makes more sense to insulate the larger area first. Furthermore, the performance (R value) of double glazing windows is lower than that achieved by installing ThermoWall into existing wall cavities.

Let’s take an example of a house with a vertical wall area of 100 m2.  If 25% of that is windows then 75 square metres is walls. This area can be insulated withThermoWall for $4,000 to $5,000. Retro-fit of double glazing is currently quoted at between $250 and $500 per square meter.  At a median of say $375 per sqm, the cost will be $9,375 for just 25% of your homes wall area. This is an efficiency 500% less than having the walls insulated with ThermoWall.


Do you require a building consent for installing ThermoWall?

Yes, a building consent is required for installing any form of insulation into the exterior walls of an existing home.  We work with you to get a building consent for prior to installation of ThermoWall.