Inquiry #10

How can New Zealand homes be

more effectively insulated report

Introduction:

Cold homes in New Zealand are a big problem, people all around New Zealand have a cold home and there are many health issues caused by this. It is a big problem that has to be solved, every Kiwi family has faced cold, damp and mouldy homes and it’s not good both for health and wellbeing. Through this inquiry I have done a lot of research and came up with a solution to this problem. I have created a PMI and analyzed through some criteria and found the best solution. The solution is having wall insulation and installing PVC windows on the current New Zealand homes structure. This is the best combination of solutions because all the other ones were very expensive and the whole New Zealand home structure would have to be changed and not everyone can afford this.

How big is this problem?

Cold homes in New Zealand are a big problem because around a third of homes are too cold in winter and too warm in summer.More than 75% of New Zealand homes have poor and insufficient ceiling insulation and 70% where the floor could be insulated, have no underfloor insulation.

How are New Zealand homes insulated?

In New Zealand a standard home doesn’t have many types of insulation. A home usually has ceiling insulation, floor insulation and most new homes have double glazing. For ceiling insulation the most commonly used material is wool, the material that is used to insulate underfloor is most commonly polyester sheets, however there are a few more materials used such as polystyrene and glasswool. Above the ceiling there usually are wool laybeds laid down in rolls, this prevents cold/heat coming in and going out through the ceiling.

Another most commonly used insulation is double glazed windows. Double glazed windows have two panes of glass spaced by around half a centimeter gap and between them containing air or argon gas (argon gas is a better insulator than air). Argon gas basically minimizes the transfer of heat through the glass. The gas is colourless and odorless and has been used in window manufacturers for years.As NZ home insulation explains there is another way that some homes are insulated to a higher standard, and this is insulating the walls. As we all know, if you knock on a New Zealand home’s wall you can hear that it’s hollow, wall insulation is installed in these hollow gaps as either segments or blankets. Pumped into the walls through small holes, it is usually made from urea formaldehyde foam, wool or glass fibers and polystyrene beads.

Another part of the house that is usually not insulated in a New Zealand home is the garage big door. In most NZ homes the garage is the coldest and hottest room as it has a big metal door that is poorly sealed. There are few garage doors in NZ that are insulated, by insulated I mean that the garage door is not just a metal sheet, but it’s usually hard plastic with insulator materials inside.

How are other homes around the world insulated?

There are many ways that homes around the world are insulated but they usually are all similar if not the same. For example, back when I used to live in Italy the house me and my family lived in was made out of bricks. There are a small variety of these “bricks”. The most commonly used ones are AAC blocks and Poroton blocks (Poroton blocks are the blocks that my current house here in NZ is made out of). As German Kiwi builder (building company that built my home) explains, AAC blocks are a European building system that has been around for years. These blocks can be used for walls, floors and roofs. The website explains that these bricks are very good as they offer excellent thermal insulation.

Poroton blocks are a special clay block used to build highly insulated walls without a cavity. The blocks have a honeycomb like-pattern when viewed from above. Another great way that not only in Italy but all over Europe, homes have PVC joinery which insulation. In New Zealand window frames are made out of aluminium, aluminium is not a great insulator as it’s a great heat and cold conductor which means if it’s hot on the outside then it will transfer the hot inside and vice versa with the cold. This will also lead to your windows having a lot of condensation in the cold times of the year.

Vinyl (uPVC) windows are the most commonly used window frame type in North America and in Canada. As awareness of their benefits grows in New Zealand. One major reason for its increase in popularity as Why PVC? explains because PVC is an insulator, unlike aluminium. It keeps your home more comfortable by reducing the heat and cold transfer through your window frame. This leads to eliminating condensation too. From personal experience these frames are really good as when you wake up from a cold night outside you have no condensation and the frame feels room temperature to the touch.

What are some alternative ways to insulate a home in New Zealand?

There are basically two answers to this question, one is change the way homes are built in New Zealand to brick homes or else keep the same structure and materials, however switching to PVC joinery and wall insulation. This is because most homes in New Zealand have ceiling and floor insulation. Changing to PVC joinery and having wall insulation would change dramatically the temperature in a Kiwi home, you would be much more comfortable and have a nice warm home. Another way that could improve your home insulation is to have a double layer of wool on the ceiling making your home slightly warmer. One of the cons of PVC joinery is that it costs a lot of money and not everyone can afford it. The really good thing about PVC is that there are zero air leaks in the gaps in your main doors and windows which will help minimize the heat dispersion. PVC window frames can cost up to $500 NZ dollars per square metre. If not everyone can afford this then there either will have to be a change to a standard New Zealand home insulation/build style.

Does the environment you live in affect whether you need better insulation?

In New Zealand there is a big difference in how some homes should be insulated between the North and South Island. Say you are living in Tauranga, the lowest temperature in winter is about 10-4C°. However, say you are living in Dunedin, the weather is really cold there in winter and in the summer. The temperature in summer is 11-20C° maximum and in winter it can go down to snowing temperatures such as 4-13 during the day which is what we get here in Tauranga during the night.This means that in Dunedin homes should be insulated to a higher standard as it’s colder throughout the whole year. The thing is most people just deal with the cold, they put on a jumper or two, turn on the heater to max and heat the one room they spend most of their time in. If we changed to better insulation this would not happen. You could heat your home every couple of hours and it would stay the same temperature.

Numerical data:

This graph above shows the average indoor temperature in 2018/2019 in New Zealand homes. As you can see the different colour lines show the different seasons of the year. There are a few homes with 25+ degrees in the house and the average temperature 20-24 during summer, autumn, winter and spring. This graph also shows that in winter there is the highest percentage of homes that are too cold. The temperature peaks in autumn around 24 degrees and at a percentage of 62% of homes. From this graph I can clearly understand that there is a lot of variation in temperature percentages in New Zealand homes. However the homes that are graphed warm in the winter are most likely to have the heating on nearly 24/7 trying to keep your home warm, however spending a heap of money on electricity bills.

What are the effects of a poorly insulated home?

For this part I decided to look and explain two main ones, the health side to the problem and the effects on your home. I tried to include some positives but there are basically no positives.

Health:

After reading an article on Cold homes impact on health I realized that there are a few health issues that can come from a poorly insulated home that you live in. We all spend around 90 percent of our time when we are at home indoors and for that reason the environment and its effects on our health are more important than is usually assumed.Many New Zealand homes have a few features that can lead to health issues. One of the biggest problems is that New Zealand homes are just too cold. This cold temperature indoors can lead to dampness and dampness leads to mould. This issue is usually seen in older homes but can also be seen in the newer homes that are being built. The World Health Organization recommends a minimum of 18° indoor temperature and if there are babies or elderly people it should ideally be 21°. However the daily average temperature in a New Zealand home is 16° which can be very cold and can lead to possible health issues.

More than a third of New Zealand homes have mould. Most mould is not harmful to healthy people, however some types of mould release substances which can be toxic and cause a reaction to some people. Another thing about some moulds is that, if you inhale it, for some people it may cause skin rashes and many other skin problems. This all leads back to the question “why are homes so cold?”. This is not because the heating system you have is not efficient, it’s the poor insulation that is not effective in keeping in the heat.

Effects on your property:

Most of these effects I have already mentioned in health problems however I will go deeper into describing what could happen to your home if you have bad insulation. Poor insulation can lead to dampness and will create mould around your walls and corners where it’s not ventilated. Cleaning your home from mould and damp spots can be really expensive. If you live in an area that can go to freezing temperatures another problem that can occur is frozen water pipes, this usually occurs if you don't have pipes that are properly insulated. This problem is very expensive and hard to fix however it is not a problem we are facing here in Tauranga. Another big problem that could happen from a poorly insulated home is that your window sill corners can start to rot from the condensation that comes from the aluminium joinery.

What are the best types of insulation that should be used in NZ?

After doing some research I found a few, first I will explain the ones that are used by few and then the ones that should be used but are not too familiar to New Zealanders from other countries that would be effective. There are five types of insulation types that New Zealanders are familiar with but not everyone uses them (wool is what most Kiwis use for ceiling insulation and polystyrene for underfloor insulation).

Fiberglass insulation:

This is the type most familiar to Kiwis, it’s commonly made from recycled glass and it offers great thermal insulation. It traps heat more than most of the other materials of the same thickness.The downside of this insulator is that fiberglass can be irritating to the eyes and skin, while some people have concerns about the chemicals that are used to bond the fibers together. Fiberglass is most commonly used to insulate the ceiling of a home.

Polyester insulation:

This is often made from recycled plastics, it’s a great eco-friendly way to turn waste into an insulating material. It offers decent thermal insulation especially when it’s installed in a large blanket that rolls up to cover the entire roof space including the joists. This is a great insulation method that is eco-friendly and no harmful chemicals are used to create it.

Wool and wool blend insulation:

The stuff that covers sheep can also be used to keep you home warm. It’s a natural product which makes it pleasant for the builders to handle and install. Some brands of wool insulation have resin and polyester blended in to improve it’s thermal insulation. However wool does not offer as great thermal insulation as the previously mentioned, however some people put a double layer of wool to improve the effectiveness.

Polystyrene insulation:

Polystyrene foam is a good insulator that is increasingly used in new homes as an underfloor insulation. It’s not a very eco-friendly product, however it’s a great thermal underfloor insulation material. If it is not installed by experts it can be a problem as they have to be sure to leave no gaps between the sheets, or else there can be a gap where heat can leak out and make the insulation nearly useless.

Double glazed windows:

This mainly relates to older New Zealand homes, all new homes that are being built all have double glazed windows installed. However if people that have older homes can switch windows to double glazing which is already being done by the majority of people.

Other types not familiar to Kiwis:

There are not many, I have explained these earlier in this report but I will go into more detail about how they work. The thing to take into consideration is that the first two types of insulation will completely change the building materials and style of New Zealand homes and the other one is to tweak how current New Zealand homes are built but mainly use the same material.

Brick built homes from Europe:

Poroton bricks:

This type of brick is most commonly used in Europe. Poroton blocks are a special clay block used to build highly insulated walls without a cavity. Poroton blocks work by being “breathable”, this basically means that they are able to transfer moisture inside to outside, thus eliminating the need for the residual cavity used in traditional masonry blocks.These blocks are formed with a honeycomb structure of vertical perforations which lessen the weight still keeping a great thermal resistance. These bricks are very thermal efficient, say you have 3 heaters around the house and have them running regularly you can have a pretty comfortable and warm home.

Another great thing about poroton blocks is that they are really efficient in soundproofing your home, when you’re inside you can hardly hear cars if you live close to a main road.

AAC blocks:

AAC blocks autoclaved concrete which is lightweight, eco-friendly, load bearing and very high thermal insulator. This block offers great durability and great seismic resistance. AAC blocks are unique, they are good for building internal and external walls of a house. Another good aspect of these blocks is that they are extremely workable and flexible. A common question that is asked is “Are AAC blocks better than bricks?”I found out that they have a few advantages over brick. One of them is that they are eco-friendly building materials, unlike bricks when they go through the manufacturing process they release gases that are harmful to the environment which means the manufacturing causes pollution.

PVC joinery:

This solution, unlike the previous two, doesn't change the material that New Zealand homes are built out of, but changes the window and door joinery. I am going to explain why PVC joinery is better than aluminium joinery and the reason why I made this choice after a bit of research.

PVC joinery vs Aluminium joinery:

Thermal performance:

PVC:

PVC is the most thermally efficient joinery on the market, the plastic that is combined with an internal air chamber means that no heat or cold or heat can travel through the joinery. However a downside of PVC joinery is that it’s very expensive.

Aluminium

Aluminium is the least thermally efficient type of joinery out there. Aluminium is a highly conductive metal making it transfer cold and hot really easily making your home the same temperature as it is outside. Even combined with double glazing you will still have condensation as the frame is the problem not the double glazing.

Lifespan:

PVC

PVC windows can last up to 40+ years with minimum maintenance, this basically means you don't have to worry about them aging or wearing out.

Aluminium

Aluminium has a shorter lifespan, a common problem is corrosion and pitting, as well as the corners of the frames falling apart over time.

How does the government help families in New Zealand get better types of insulation?

After reading New Zealand government website that they do insulation services but you need to meet some requirements. One of these requirements is that you must own and live in a house that was built before 2008 and live in an area that is considered low income. They also offer a few heating and cooling but that’s only after you receive the home's insulation from the government. Warmer Kiwi Homes grants can pay up to 90% of the cost of the ceiling and underfloor insulation.

I read a very interesting website on this question (Budget makes more Kiwi homes warmer and reduces emissions across sectors a council's website) and have clarified a few things from it.

Budget 2021 provides further support to ensure Kiwi homes are warmer and energy efficient. Low income workers can look forward to warmer homes thanks to Budget 2021 investment into the Warmer Kiwi homes programme.

Extending Warmer Kiwi Homes ensures more low-income homeowners will benefit from an extra 47,000 insulation and heating retrofits. Every year an estimated 28,000 children are hospitalized for potentially avoidable hospitalisation linked to cold, mouldy and damp houses. This move would improve health and reduce energy uses for a lot of families. That’s a win for people’s health and pockets, as well as the planet. This is basically the government's plan to tackle the climate emergency. What is being done right now is great, however if they provided better and new types of insulation for these low-range pay workers it would be a lot better.

What's the best option for improving home insulation In New Zealand?

To answer this question I created a PMI and brainstormed all the possible options of insulation that would be most effective. I took in mind what I read about and some expert advice. In this PMI I looked at 6 different types of insulation and after basing them off some criteria I made my decision. A mix of wall insulation with the type that you can afford and installing PVC joinery around your home would drastically reduce cold homes and improve your home’s thermal insulation. I made these choices based mainly on price and effectiveness on the thermal insulation side.

CONCLUSION

I think that the solution that I chose is best as I considered a solution that could be both effective but affordable at the same time. I based these six different solutions on efficiency, cost, time taken to build or renovate and affect on the environment. PVC joinery and wall insulation were the ones that came out with the best score, as they don’t create waste or pollution, are very thermally effective and don't cost a crazy amount of money. As for time taken to renovate wall insulation would not take too long however switching out your old aluminium joinery for pvc joinery can take up to a month or so depending on the amount of windows that you have. So in conclusion I think that the best way to improve New Zealand home insulation is a mix of Installing PVC joinery and having wall insulation as it would be most effective from many points of view.

BIBLIOGRAPHY:

Works Cited

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Words

Adrienne Kohler, and Adrienne Kohler. “Unhealthy Living.” Architecture Now, architecturenow.co.nz/articles/unhealthy-living/#:~:text=More than 75 percent of,our housing stock so bad?Unhealthy living.

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