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

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.