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New Study Reveals Alarming CO2 Levels in New Zealand Bedrooms at Night

Written by Healthy Home Team on . Posted in Insights, Ventilation.

Overnight CO₂ Levels in New Zealand Homes Could Be Affecting Your Sleep

A new study published in the New Zealand Medical Journal found that overnight carbon dioxide (CO₂) levels in some Wellington bedrooms reached more than 8,000 parts per million (ppm), around ten times the commonly used indoor ventilation target of 800 ppm.

The researchers monitored 20 Wellington homes while occupants slept and found that many bedrooms experienced high overnight CO₂ levels due to limited ventilation. While this was a pilot study, the findings suggest that similar issues may exist in other New Zealand homes, particularly where bedrooms have limited fresh air.

Why CO₂ Levels Matter in Your Home

Carbon dioxide is a natural part of the air we breathe out. In small amounts it is harmless. But when CO₂ builds up in an enclosed space, such as a closed bedroom overnight, it is a sign that the room is not receiving enough fresh air.

Poor ventilation and elevated indoor CO₂ levels have been linked to poorer sleep quality, morning headaches, tiredness, difficulty concentrating, and feeling less refreshed when you wake up. Many people put these symptoms down to stress or simply having a bad night’s sleep, when poor indoor air quality could also be playing a role.

A commonly used indicator of good indoor ventilation is keeping indoor CO₂ concentrations below about 800 ppm. The Wellington study found that many bedrooms exceeded this level overnight, with some recording much higher concentrations.

Interestingly, the researchers found that bedrooms with higher CO₂ levels were not necessarily warmer or more humid. This suggests that the main issue was a lack of fresh air rather than temperature or humidity alone.

Why Some New Zealand Homes Are More at Risk

New Zealand homes have not always been built with ventilation as a priority. Older homes often have more natural air leakage, while newer homes are generally built to be more airtight to improve energy efficiency. Although this helps keep homes warmer and reduces heat loss, it also means fresh air may not enter the home unless there is adequate ventilation.

During the night, windows and doors are typically closed. Everyone in the home continues to breathe, and without enough fresh air entering the room, CO₂ levels can steadily increase. In smaller bedrooms, or rooms with more than one occupant, this build up can happen even faster.

The Wellington study found that newer, more airtight homes often experienced higher overnight CO₂ levels than older homes. This highlights the importance of combining good insulation with effective ventilation.

The Role of Home Ventilation Systems

A good home ventilation system works by bringing fresh air into the home and removing stale indoor air. This happens continuously and quietly in the background, helping maintain better indoor air quality without relying on opening windows every day.

There are a few different types of ventilation systems available for New Zealand homes. Positive pressure systems typically introduce filtered air from either the roof space or outside, depending on the system. Heat recovery ventilation systems are a more advanced option that exchange stale indoor air with fresh outdoor air while retaining much of the home’s warmth. Both can improve indoor air quality when they are properly designed and installed.

For homes without mechanical ventilation, opening windows and doors remains one of the simplest ways to bring fresh air into the home. While this works well during warmer months, it is often less practical during winter when people naturally keep their homes closed to stay warm.

What You Can Do Right Now

If you regularly wake up feeling tired, foggy, or unrefreshed despite getting enough sleep, poor bedroom ventilation could be one factor worth considering.

There are a few simple things you can try straight away. Leaving a window slightly open overnight, even just a small gap, can help reduce CO₂ levels. Keeping bedroom doors open when practical allows air to move more freely through the home. If several people are sleeping in a small bedroom, improving airflow becomes even more important.

For a longer term solution, a ventilation system can provide a more consistent supply of fresh air throughout the year, helping improve indoor air quality regardless of the season.

Improving the Air Quality in Your Home

At Healthy Home Team, we help homeowners across New Zealand improve the comfort and performance of their homes. Good ventilation plays an important role alongside insulation and heating to create a healthier indoor environment.

If your home does not currently have a ventilation system, or you are unsure whether your existing system is suitable for your home, we can assess your property and explain the options available. Every home is different, and the right solution depends on how your home is built and how you live in it.

To find out more about improving your home’s ventilation and indoor air quality, visit healthyhometeam.nz or get in touch with our team today.

Understanding Where a Home Can Lose Heat and How Proper Insulation Can Help

Written by Healthy Home Team on . Posted in Insights, Insulation.

Where Do Homes Lose Heat?

Understanding where a home can lose heat is the first step to making your living space warmer, more comfortable, and cheaper to run. According to BRANZ (the Building Research Association of New Zealand), heat loss in an uninsulated home breaks down like this:

  • 30 to 35 percent escapes through the roof
  • 18 to 25 percent is lost through the walls
  • 21 to 31 percent leaks out through the windows
  • 12 to 14 percent seeps through the floor

That adds up fast. If your home has poor insulation or none at all, more than 70 percent of the heat you generate can disappear before it does much good. Even with a heater running all day, warm air simply won’t stay where it’s needed. This makes your home cold and uncomfortable, and it pushes your energy bills up as your heating system works overtime to compensate.

How Insulation Works to Stop Heat Loss

Insulation works by slowing the movement of heat. Heat naturally moves from warmer areas to cooler ones, so during winter, the warm air inside your home is constantly trying to escape to the colder air outside. Insulation acts as a barrier, making it much harder for that heat to move through walls, ceilings, and floors.

Most insulation materials, trap small pockets of air within their structure. These air pockets are poor conductors of heat, which means they slow down the transfer significantly. The thicker and denser the insulation, the better it performs. This is measured using an R-value, where a higher R-value means better thermal resistance and better performance overall.

Good insulation also works in reverse during summer, keeping heat out and helping your home stay cooler naturally. So while the focus during New Zealand winters is on retaining warmth, insulation delivers year-round benefits for comfort and energy efficiency.

The Key Areas of a Home That Need Insulation

Knowing where a home can lose heat points directly to where insulation needs to go. Each area of the home plays a role in overall heat retention, and addressing them together makes the biggest difference.

Ceiling and Roof

Because heat rises, the ceiling is the single biggest area of heat loss in most New Zealand homes. Ceiling insulation is often the most cost-effective place to start. Installing insulation in the ceiling space can make an immediate difference to how warm your home feels and how much energy you use to heat it.

Walls

Walls make up a large surface area in any home, so heat loss through them adds up quickly. Wall insulation is commonly installed in new builds or during renovation work, when wall cavities are accessible. For existing homes, blown insulation can be retrofitted into wall cavities without major disruption.

Underfloor

Floors account for up to 14 percent of heat loss in an uninsulated home. Underfloor insulation fits between the floor joists beneath your home and creates a barrier against the cold ground below. Homes with suspended timber floors benefit the most from this type of insulation, and it can be retrofitted without disturbing the interior of the home.

Why Getting the Right Insulation is Important

Installing insulation in just one area of your home will help, but a whole-home approach delivers the best results. If you insulate the ceiling but leave the floor and walls bare, heat will still find a way out through those gaps. Addressing each area together means your home holds warmth more effectively, your heating system doesn’t have to work as hard, and your energy bills reflect that.

New Zealand homes, particularly older ones, are often under-insulated compared to current building standards. Many homes built before the 1990s have little to no insulation at all. This is one of the reasons so many New Zealanders struggle with cold, damp homes during winter. The good news is that retrofitting insulation is straightforward in most cases, and the long-term savings in energy costs often outweigh the upfront investment.

Proper insulation also contributes to a healthier home environment. Cold, poorly insulated homes are more prone to condensation and mould growth, which can affect air quality and the health of the people living there. Keeping your home warmer and drier reduces these risks significantly.

Talk to the Healthy Home Team About Insulation for Your Home

At Healthy Home Team, we help New Zealand homeowners understand exactly where their home is losing heat and what they can do about it. Whether you are starting from scratch or looking to upgrade what you already have, our advisors can assess your home and recommend the right insulation solutions for your situation.

Getting your home properly insulated is one of the most practical things you can do for your comfort, your health, and your wallet. Get in touch with the Healthy Home Team today to find out how we can help you create a warmer, healthier home this winter and beyond.

BRANZ HEEP2 Report Shows Kiwi Homes Are Warmer, But Bedrooms Are Still Too Cold

Written by websites@emd.agency on . Posted in Insights.

BRANZ, the Building Research Association of New Zealand, has released new findings from its Household Energy End-use Project 2, known as HEEP2.

The latest report focuses on indoor temperatures in New Zealand homes. It uses detailed monitoring data from more than 250 households, along with householder surveys and building assessments. HEEP2 builds on the original HEEP study, which ran from 1999 to 2005, giving researchers a way to compare how homes have changed over the past 20 years.

The results show some clear progress. New Zealand homes are warmer in winter than they were two decades ago. Living rooms are now, on average, much warmer throughout the day. Evening living room temperatures now average 20.4°C, which is above the recommended minimum indoor temperature of 18°C.

But the report also shows there is still work to do. Many homes still fall below healthy temperatures, especially in bedrooms overnight and early in the morning.

Key Findings from the HEEP2 Report

The HEEP2 indoor temperature report shows that New Zealand homes are performing better than they were 20 years ago, but many still do not stay warm enough throughout winter.

Despite overall improvement, bedrooms remain a major concern. The report found that average bedroom temperatures drop to 16.5°C overnight and around 15.7°C by morning. Forty-one percent of overnight bedroom readings were below 16°C, and 18% were below 14°C.

Heating patterns help explain some of this difference. Most households heat their living areas regularly in winter, but bedrooms are heated far less often. Many bedrooms are never heated.

The report also found that draughtiness and poor building envelope condition are linked with colder indoor temperatures. Homes with moderate or major draught risks were more likely to be colder than homes with minor or no draught risks.

Damp, condensation, and mould are still common issues. Around three-quarters of monitored households reported condensation on windows in winter, and many households also reported dampness or mould.

Another important finding is summer overheating. Many homes stayed warm into the evening and overnight during summer, including bedrooms during sleeping hours. This shows that homes need to be designed and improved for both winter warmth and summer comfort.

What Homeowners Can Do

Most of the issues highlighted in the HEEP2 report can be improved. The right solution depends on the home, but there are some common areas worth checking.

Improve Insulation

Insulation helps slow heat loss in winter and heat gain in summer. Ceiling and underfloor insulation are often the first areas to check, especially in older homes. Wall insulation can also make a big difference where it is missing or poorly performing.

A home assessment can help identify whether insulation is missing, damaged, poorly fitted, or no longer performing as it should.

Use Efficient Heating

The report shows that heat pumps are now much more common than they were during the first HEEP study. Heat pumps are an efficient way to heat living areas and can also provide cooling in summer.

A good heating system needs to be correctly sized for the space. It also needs to be used in a way that helps the home stay warm, especially during cold mornings and evenings.

Check Bedrooms

Bedrooms are one of the main areas of concern in the HEEP2 report. Many bedrooms are not being heated regularly, even though they often fall below healthy temperatures overnight.

Homeowners may need to look at better heat transfer, direct bedroom heating, improved insulation, draught stopping, or a whole-home approach that helps keep temperatures more stable from room to room.

Manage Draughts

Draughts can let cold air into a home and make heating less effective. Gaps around doors, windows, floors, and skirting boards can all contribute to heat loss.

Draught stopping is often a low-cost improvement, but it can make a noticeable difference when combined with good insulation and heating.

Control Moisture and Ventilation

Condensation and dampness are still common in many New Zealand homes. Moisture can come from cooking, showering, drying clothes indoors, ground moisture, leaks, and poor ventilation.

Good ventilation helps remove moist air from kitchens, bathrooms, and bedrooms. In some homes, this may mean better extractor fans, improved airflow, ground moisture control, or a ventilation system suited to the home.

The right approach depends on where the moisture is coming from.

Think About the Home as a System

One of the strongest messages from the HEEP2 report is that homes perform best when the whole house works together.

The Above-Code homes in the study showed that healthier and more stable indoor temperatures are possible. These homes performed better because of a mix of improved building envelopes, good design, effective heating, cooling, and ventilation.

This matters because one upgrade on its own may not fix every issue. A heat pump will work better in a well-insulated home. Insulation will perform better when draughts and moisture are managed. Ventilation works best when it is part of a wider healthy home plan.

What You Can Do Right Now

The HEEP2 report shows that New Zealand homes have improved, but many are still not warm enough where it matters most. Bedrooms, draughts, dampness, condensation, and uneven heating remain common issues.

The best first step is to understand how your own home is performing.

A Healthy Home Team assessment looks at insulation, heating, ventilation, moisture, and draughts. This gives you a clear picture of what is working, what needs attention, and which upgrades are likely to make the biggest difference.

With the right advice and the right improvements, many homes can become warmer, drier, and more comfortable throughout the year.

Get in touch with the Healthy Home Team to book a healthy home assessment.

A healthy home

What is a Healthy Home? 

Written by Healthy Home Team on . Posted in Insights.

A healthy home is one that feels warm, dry, and safe to live in. It protects the people inside, especially during winter when cold and damp conditions can increase the risk of illness and lead to high power bills. 

Many houses in New Zealand were built before modern building standards were introduced. As a result, thousands of homes are still poorly insulated, hard to heat, and prone to moisture problems. Creating a healthy home means fixing these issues so that every room is comfortable and energy efficient year-round. 

The Benefits of a Healthy Home 

Living in a healthy home makes life easier and more comfortable. The benefits include: 

  • Lower power bills 
  • Improved energy efficiency 
  • Warmer and drier living spaces 
  • Reduced heat loss 
  • Less risk of illness caused by damp and mould 

These improvements don’t just make your home nicer to live in, they also support long-term health and wellbeing. 

What Makes a Home Healthy 

A healthy home needs the right balance of warmth, ventilation, and moisture control. Insulation is one of the most important parts. It slows down heat loss, which keeps warmth in during winter and heat out during summer. Without it, homes are expensive to run and often cold. 

Ventilation is just as critical. Fresh air helps remove moisture and stale air while reducing condensation and mould. Using extractor fans in kitchens and bathrooms, or installing a home ventilation system, makes a noticeable difference. 

Heating is also essential. A properly sized heat pump or another fixed heating system can keep living areas warm without pushing power bills up. Other simple improvements like sealing draughts, installing a ground moisture barrier, and choosing energy-efficient appliances all help to create a healthier living space. 

When insulation, ventilation, and heating work together, your home will be warmer, drier, and more comfortable to live in. 

The Healthy Home Standards 

The New Zealand Government introduced the Healthy Home Standards to improve housing quality, particularly in rental properties. Cold and damp homes have been a long-standing issue in New Zealand, with many families living in houses that are difficult to heat and prone to mould. These conditions can cause asthma, respiratory problems, and other health issues. 

The standards set minimum requirements in five key areas that have the biggest impact on indoor warmth and dryness. These are insulation, ventilation, heating, moisture and drainage, and draught stopping. Landlords must meet these standards for rental properties. For homeowners, they act as a useful guide for what makes a home healthier and more energy efficient. 

Insulation 

Insulation is required in ceilings and under floors of rental homes, and it must meet minimum R-values. If insulation is old or damaged, it needs to be topped up or replaced. Even if your home has some insulation already, it may not be enough to perform properly. Many older homes in New Zealand had no insulation when first built, so upgrading it can make a big difference to comfort and power costs. 

Ventilation 

Good ventilation removes damp air and brings in fresh air. Under the standards, rental homes must have extractor fans in bathrooms and kitchens, and every habitable room must have windows or doors that can open to the outside. 

If you notice condensation on windows or the air feels heavy, your home may not have enough ventilation. Improving airflow helps keep homes healthier and reduces the risk of mould growth. 

Heating 

Rental homes must have a fixed heating device in the main living room that can warm the space to at least 18°C on a cold day. This is the minimum temperature recommended by the World Health Organization for healthy living. Heat pumps are a common and efficient choice, but other approved fixed heaters can also be used. 

Even with a good heater, homes can lose warmth quickly if insulation or ventilation are not up to standard, which is why all three need to work together. 

Moisture and Drainage 

Homes must have proper drainage systems including gutters, downpipes, and drains to remove rainwater. Houses with a subfloor space may also need a ground moisture barrier to prevent dampness rising from the soil. 

Moisture is a hidden problem in many New Zealand homes. Left untreated, it can damage building materials, encourage mould growth, and make heating less effective. 

Draught Stopping 

Any unnecessary gaps or holes must be sealed, such as around windows, doors, floorboards, and unused chimneys. Even small draughts can make it harder to hold in heat. A well-sealed home stays warmer for longer and is cheaper to heat. 

Take the Next Step 

Creating a healthy home is about making practical changes that improve warmth, dryness, and energy efficiency. The Healthy Home Standards provide a clear guide to what works, but every house is different and may need a tailored plan. 

If you want to find out how your home is performing, book a Healthy Home Assessment with one of our local advisers. We can show you what improvements will make the biggest difference so you can enjoy a warmer, drier, healthier home. 

EECA Warmer Kiwi Homes Grant

The EECA Warmer Kiwi Homes Grant Has Been Expanded – What Does That Mean for Homeowners 

Written by Healthy Home Team on . Posted in Insights.

The EECA Warmer Kiwi Homes programme helps New Zealanders make their homes warmer, drier, and more energy efficient. It provides funding towards the cost of insulation and heating for eligible households, reducing the upfront cost of these important upgrades. 

Since the programme began, over 170,000 heating and insulation projects have been completed across the country. Helping thousands of families live in healthier homes. Now, the Government has expanded the programme so more people can access support. 

What is EECA Warmer Kiwi Homes 

Warmer Kiwi Homes is managed by the Energy Efficiency and Conservation Authority (EECA). The programme provides grants of up to 90% towards the cost of ceiling and underfloor insulation for households in the most financially stretched communities. It now also funds up to 90% of the cost of an energy-efficient heater. 

Until now, eligibility was mainly limited to low-income households or those in the highest deprivation areas. The grants have made it possible for many families to make improvements that would otherwise have been out of reach. 

What Has Changed 

From 5 August 2025, the eligibility criteria have been widened to include more middle-income households. This means thousands of homes that did not previously qualify could now get financial help. 

The biggest change is for households in deciles 5 and 6 on the deprivation scale. These households are now eligible for a 50% grant towards insulation. This support was not available before. 

Other key updates include: 

  • Households in decile 7 will still be eligible for insulation grants. The grant rate has changed from 80% to 50%. 
  • Households in decile 8 will keep their 80% insulation grant, but heating grants will no longer be available for this group. 
  • Households in the highest-need categories (deciles 9 and 10, and those with a Community Services Card or SuperGold Combo Card) will continue to receive up to 90% for insulation and up to 90%, capped at $3,450 for heating. 

These changes are expected to make up to 300,000 more homes eligible for insulation grants. 

Why This Matters for Homeowners 

A well-insulated home is easier to heat in winter and stays cooler in summer. It also helps reduce power bills and improves overall comfort. EECA data shows that good insulation can save around $340 a year in heating costs. 

Expanding the Warmer Kiwi Homes programme means more people can make these improvements sooner. Even if you did not qualify before, you may now be eligible for a 50% contribution towards the cost of insulating your home. 

Heating grants remain targeted to those most in need, but for many households, improving insulation is the first and most effective step towards a warmer, drier home. 

How to Check if You Qualify For Warmer Kiwi Homes Grant

Eligibility is based on where you live, whether you have a Community Services Card or SuperGold Combo Card, and your area’s deprivation decile rating. With the updated rules, even some households in the middle-income range may now be able to access funding. 

If your home is in deciles 5, 6, or 7 and you have not been eligible before, it is worth checking again. The new grant rates could significantly reduce the cost of insulation work. 

Applications made before 5 August 2025 will be assessed under the old rules unless the new rules give a better result. If the new rates are better for you, your installer can requote your job before installation takes place. 

Take the Next Step 

At Healthy Home Team, we help homeowners understand what funding is available with the EECA Warmer Kiwi Homes programme and can connect you with an approved service providers.

If you have been thinking about insulating your home or improving your heating, now is the time to see if you qualify. With the expanded programme, thousands more New Zealanders will be able to make their homes warmer, healthier, and more energy efficient. 

Contact Healthy Home Team todayto find out if you are eligible for the EECA Warmer Kiwi Homes grant. Start your journey to a warmer, healthier home today.