WHY BUILDING A STANDARD HOME TODAY IS A BAD INVESTMENT.

New Zealand has made a commitment to being carbon neutral by 2050. The standards of how we live are beginning to change and will continue to do so until we have met our obligations in accordance with the Paris Climate Agreement.

According to the MBIE (Ministry of Business, Innovation & Employment), approximately 20% of New Zealand’s carbon emissions are created through the heating and cooling of our buildings. 

MBIE states “The Building & Construction Sector needs to play it’s part in meeting this goal” and aims to start bringing out code changes in 2024. 

So what is changing? 

There are two main areas of construction the MBIE wants to adapt:

  1. Transforming Operational Efficiency – Changing the way our homes use energy (e.g. heating & cooling, hot water, lighting, ventilation etc). 
  2. Whole-of-Life Embodied Carbon Emissions Reduction – This looks more at the sustainability of the materials being used to build our homes. 

Energy usage is measured in kwh/m2-a (average electricity consumption per square meter). Currently, NZ homes are averaging at 120kwh/m2-a

In 2024, the first stage of changes to the Building Code will take place. The indication of this change is that all new builds must not exceed 60kwh/m2-a in power consumption (half of what is used now). To make these changes, homes will need to have upgraded insulation and heat recovery ventilation units fitted – the problem we are facing currently is NZ is experiencing a huge demand for housing, a lot of which is being converted to new builds. 

A huge majority of these new homes are being built in the most affordable way possible (the minimum building code standard), which often means extras like upgraded insulation, windows, air tight wraps and ventilation are not at the forefront of the new home owners mind. It is a common mindset to spend more money on aesthetics than on functionality. However, this way of thinking will result in huge losses or homes that are unable to be sold. 

By 2024, your standard home will no longer meet the minimum requirements for living. If you go to sell this home, it would be like selling a single glazed home with no insulation in todays’ market. Please keep this in mind before you build! It is far easier and more cost effective to upgrade the structure of your home before it is built rather than a few years later before you try to sell it. 

TIMELINE OF CHANGES:

60 kwh/m2-a by 2024

30 kwh/m2-a by 2028 (OUR CURRENT ENERGY EFFICIENT STANDARD)

15 kwh/m2-a by 2035 (PASSIVE HOUSE STANDARD)

To learn more about the changes to the building code: read the MBIE Building for Climate Change: Transforming Operational Efficiency document here

If you’re thinking of building, have a chat to our team to learn how we can help you secure your investment!

HAND OVER TO KAT & GRANT

Last week we handed over a brand new energy efficient home to our lovely clients Kat & Grant. This 3 bedroom home in Prestons Park has been kit out with all of our standard energy efficient upgrades including: low-e coating, argon filled uPVC windows from NK Windows, airtight ProClima wrap, upgraded insulation and the Stiebel Eltron Heat Recovery System.

This home was designed by our Passive House Certified designer to maximise the solar potential in winter and decrease the solar gain in summer. Kat & Grant were a joy to work with and we feel privileged to have been a part of their journey.

PASSIVE HOUSES & YOUR HEALTH

Our homes are supposed to be our safe places, but for nearly a third of New Zealanders, damp homes can have a serious effect on our health.

Damp, mouldy houses and the link to respiratory problems

Damp, poorly ventilated houses encourage mould growth. For healthy individuals, mould may not have a significant impact, but if people have underlying health issues, damp, mouldy homes can lead to or worsen breathing problems.

The Asthma and Respiratory Foundation NZ reports that one in six New Zealanders lives with respiratory illness – that equates to 700,000 people. It is estimated that the yearly costs associated with respiratory disease are $5.5 billion. While not all respiratory problems are caused by damp houses, it is best to limit exposure to damp and mould.

Sources of indoor moisture

All occupied homes accumulate moisture – the simple act of breathing contributes 0.2 litres (L) per hour per person. Other sources include normal household activities like cooking, cleaning and bathing. The Energy Efficiency and Conservation Authority (EECA) estimates the average New Zealand family produces around 8 litres of moisture in their homes every day.

SourceAmount
Breathing (per person)0.2 L per hour
Perspiration (per person)0.03 L per hour
Shower/bath (per event)1.5 L
CookingUp to 3 L
Dishwasher (per load)1 L
Clothes drying (per load)5 L
Clothes washing (per load)0.5 L
Science Learning Hub

(Figures produced by the University of Otago and reported in the New Zealand Herald and the Science Learning Hub)

Moisture also enters houses from the outside. Leaks in the roof, around windows or in the plumbing allow moisture to get between the walls or floors.

How Passive Houses combat unhealthy environments

An increase in insulation, air tight envelopes and mechanical ventilation all aid in combating dampness in homes and improving quality air.

By adding quality insulation, you are increasing the thermal resistance of your building envelope. Increased thermal resistance means less energy transfer between the outside and inside air, so the air within your home isn’t mimicking the external temperatures. It is important to maintain healthy living temperatures within your home so your immune system isn’t constantly working overtime.

To insure your efforts towards insulation are not in vain, your home needs an air tight & waterproof barrier. By replacing your standard building paper with the likes of the ProClima system, your home will be surrounded by a 100% waterproof, air tight membrane. The ProClima Sysytem prevents any moisture from entering your thermal envelope and therefore keeps your insulation dry and effectively working. Most damp homes do not start damp… Their thermal resistance decreases due to damp, shrunken insulation that no longer performs properly. This damp insulation can begin to grow mould and fungi which attributes to polluted air.

An airtight barrier also prevents your home from losing heat energy through gaps in the building envelope, maintaining your air tempertaure for longer.

Although an air tight barrier prevents external moisture from entering the home, it does not irradicate the internal moisture created by those living in the home – in fact, it makes this moisture worse as it has no where to escape. To combat internal moisture, you need Mechanical Ventilation. Mechanical Ventilation Systems need to be installed within your thermal envelope (insulation layer) to work effectively.

Mechanical Ventilation Systems such as Heat Recovery Units are the best at filtering the air coming into your home, removing moisture and transferring heat simultaneously. By taking the energy from the extracted (damp) air and reintroducing it to the filtered fresh air being brought into your home, you will not need to spend money heating the new air with the likes of a heatpump. Most Heat Recovery Units on the market claim to recover approximately 90% of heat energy (meaning if it is 0°C outside and 20°C inside, the new air being introduced into the home will be approximately 18°C).

We should all be breathing filtered air

Exposure to CO2 and other common pollutants (such as Nitrogen Dioxide) can produce a variety of health effects. These may include headaches, dizziness, restlessness, a tingling or pins or needles feeling, difficulty breathing, sweating, tiredness, increased heart rate, elevated blood pressure, coma, asphyxia, and convulsions. By filtering out CO2 and other pollutants in the air we breath, we can reduce the impact these carbons have on your body, overall improving your quality of life.


STATE OF OUR AIR

Ministry for the Environment – NZ

This article outlines some of the main pollutants that affect our health and environment. It includes information on standards and guidelines for managing levels of pollutants.


COMFORT & ENERGY EFFICIENCY

The World Health Organization recommends a minimum indoor temperature of 18°C – ideally 21°C if babies or elderly people live in the house.  The average daily indoor temperature in the winter for most New Zealand houses is just 16°C.

Comfort and health come in hand in hand – when you live in a warm, comfortable environment your health will improve. Studies by Stats NZ showed that 1/3 of homes lay outside what is determined by the Building Research Association of New Zealand, to be a comfortable indoor temperature (rated 20–25oC). See the study here. Something important to note: the temperatures recorded during this study were taken between late morning and late afternoon (in the kitchen or living areas). We would expect during the night, temperatures would drop further and more than just 1/3 of homes would be deemed “uncomfortable”.

It is a known fact that many NZ households will heat their living areas and neglect their bedrooms. Many elderly and children are sleeping in temperatures below 16°C. 45% of those living in these homes said they could see their breath inside during winter. These conditions can exasperate any pre-existing health conditions as well as compromise your immunity.

There is an equal amount of homes overheating during the Summer and experiencing internal temperatures of above 25°C. When we overheat, we can become dehydrated, lathargic and dizzy. Your ability to perform tasks can become impaired as your body is working overtime to cool itself.

Heatpumps are a temporary solution.

Heatpumps and other forms of heating are a solution to this problem, however they are only a band-aid covering what is a much more serious issue. Once a home has experienced a cold and damp environment, this moisture gets trapped within your walls and is very difficult to irradicate. Moisture within your walls can create mould and fungi, affecting your insulation performance and furthering the dampness of your home.

By using a heatpump you will be able to achieve comfortable living temperatures BUT the heating normally isn’t sufficient to warm your entire home and as soon as you turn off your heatpump, your indoor temperature will begin to drop drastically. This is because the majority of “uncomfortable” homes are not air tight – they leak like a sieve and mimick the outdoor temperature. All of the money you spent on power trying to heat your home literally goes out the door.

The actual solution:

Building an Energy Efficient or Passive Home safe guards you from the effects of cold environments and overheating. By upgrading your insulation, creating an air tight building envelope and using mechanical ventilation you can easily maintain a comfortable indoor temperature of 18-25°C.

Upgrading your insulation will give your walls, ceiling and floor a higher R Value (thermal resistance) meaning the cold (or heat) from outside has a harder time making it’s way into your home. By making your home airtight (with a waterproof/airtight barrier such as the ProClima system) you further prevent any moisture / cold air from entering your building envelope. You will still need a heater to bring the air tempertaure to a comfortable level, but once that temperature has been achieved, it can be maintained effciently using a Mechanical Ventilation / Heat Recovery Unit. These units ensure all areas of your home are kept the same temperature, the fresh air coming into your home is filtered (and heated using the energy extracted from the air pumped out of your home) and all moisture is irradicated.

Further to this, you can design your home with reduced thermal bridges. Thermal bridges are a component of your build that are not insulated and therefore conduct energy – these can be anything from lintels to metal brackets. By reducing the amount of thermal bridges there are in your home, you are limiting the opportunities for heat to escape from inside your building envelope. Upgrading your windows will also make a huge difference in heat transfer and reducing moisture.

HOW EXPENSIVE IS AN ENERGY EFFICIENT HOUSE?

Site: The perfect site for an Energy Efficient Home is South – North facing (with living areas being to the north) and shelter from the East and West. These types of sites are very popular and either go very quickly or are more expensive.

Design: Compared to a stock standard NZ Building Code home, Energy Efficient and Passive designs require a higher level of attention to detail. Because of this, the drafting of Energy Efficient/ Passive House plans takes longer and therefore the cost of plans increase. We charge $140ph as a base rate for our design fees – however, if you choose to build with us, we will reduce the design fees to our cost price of $75ph. You can expect energy efficient plans to take an average of 70-90 hours (keep in mind – every design has it’s own challenges).

Build: the build time of an Energy Efficient Home takes longer than a standard build by about 1-2 months as far more care and detail goes into the build and installation of products. The build is where 85% of Passive Houses fail so we need to take our time during this phase to ensure everything is installed correctly and to a high standard – due to this increase in build time, the build cost goes up.

Add ons:

  • Additional insulation – to insulate your walls, floor and ceiling you can expect to pay double overall compared to a standard build.
  • Upgraded windows – triple glazed uPVC windows with Low-E coatings and argon gas are approximately 2x the amount of standard double glazed aluminium.
  • Mechanical ventilation – the cost of these differ depending on brand and function. On average a Mechanical Ventilation system will cost you approximately $10- 15k plus install
  • Air tight wrap – the ProClima system comes in at approximately $10 -15k plus install.

We suggest allowing $2400 per m2 to build an Energy Efficient Home.

All of the prices given are a rough estimate based on a single story, passive shaped (square floor plan), 4 bedroom home as of June 2021.