Te whakapai ake i te toitū o ngā kāinga onāianei
Improving sustainability of existing homes

Wellington City ratepayers qualify for a free assessment for energy efficiency or advice around building or renovating sustainably.

The Home Energy Saver assessment is an approach that looks at ways you can reduce water and energy use. You can also ask about solar generation and making your home EV-ready.

The Green Building Home Energy Assessment is for anyone who is planning a new build or renovation and wants to get advice on energy-efficient and sustainable design. The best time is to schedule an assessment prior to the detailed design phase, but they can offer advice on sketches, photos, and high-level ideas.

Register for an assessment

The free HomeFit Online check is a simple way to see whether your home meets the Government’s Healthy Homes Standards.

Find out more about HomeFit

The World Health Organisation (WHO) recommends that your home’s indoor air temperature should be between 18-24C.

Humidity should be kept below 60%, and ideally between 30-50%. It is especially important to make sure sleeping areas are healthy for the young and elderly, and anyone with a vulnerable immune system.

Wall-mounted sensors measure the temperature and humidity of different rooms and can show you which areas need attention.

We recommend putting sensors in every bedroom and the main living area.

You can buy sensors online or at electronics and trade stores.

It's hard to keep a drafty home warm and comfortable. Cold air can force its way through gaps around doors, windows, and floorboards.

• Draft excluders are a cheap and effective way to keep drafts out from doors that don't touch the floor. Automatic weather seals and brush strips are available from the hardware store. Or you can make your own one following these guides: How to make a draught excluder – The Guardian and Draft blocker from pool noodle – Instructables.
• Window gaps around wooden frames can be blocked with V-Seal, or a similar flexible vinyl stripping that can be pushed into gaps. For aliminium frames it's best to get a professional.

Up to 30% of heating can escape through the windows.

Properly installed curtains are a cost-effective option for decreasing heat loss and energy bills.

Make sure the bottom edge of the curtain rests on the floor, and use a minimum of two layers of fabric for insulation.

• Curtains and blinds factsheet: Practical advice on what type of curtains or blinds to install and how to install them.
• Wellington Curtain Bank: Provides pre-loved curtains to low-income families and individuals in Wellington.

Many homes in Wellington were built before insulation was widely used, and get limited sun.

Insulation is one of the best ways to improve existing homes.

Better insulation can:

• help lower your heating bills
• keep you warmer and healthier.

Use the highest insulation R-value you can, especially in your roof cavity, and make sure any existing insulation is not degraded, wet, torn, or gapping.

For more information:

• Insulation fact sheet - Eco Design Advisor
• Smarter homes - Insulation Guide
• Renovate guide for different styles of houses.

Windows are an essential part of a home but can account for considerable heat loss in winter. Whether you are looking to improve existing windows or upgrade, there are some important things to consider like placement, frame type, glazing and size.

• Windows Factsheet gives practical advice on what to look for in new windows, or how to improve your existing windows.
• Gen Less provides window solutions to fit most budgets.
• Insulation films and bubble wrap are cost-effective and simple solutions to insulate your windows if you're unable to upgrade, or if you're renting.

Ensuring your home is properly insulated and using an efficient and clean heat source can help reduce your heating costs and keep you healthier.

Understand your own heating

• Use the Heating assessment tool as a guide to calculate your living room heating in line with the updated Healthy Homes Standards.
• Understand the pros and cons of different heating options, and find a good fit for you: Smarter homes - Heating systems.

Proper ventilation removes damp air and ensures your home is a healthier and warmer place to live.

Whole-home, balanced-pressure ventilation systems are ideal, but here are some simple things you can do as an alternative:

• open windows on opposite sides of the house for 10 minutes every day, even in winter
• install and use kitchen and bathroom extractor fans, or open windows when cooking or showering if there's no extractor fan
• keep bathroom and laundry doors closed when in use
• avoid drying clothes inside

For more information:

• Tackle dampness: Damp air is harder to heat and is linked to the large number of respiratory issues across New Zealand.
• GenLess - Ventilation resources: Provides a checklist and information on the different home ventilation systems.

Hot water heating accounts for around 1/3 of your energy bill.

The most efficient and low carbon methods of water heating are hot water heat pumps and solar hot water systems.

• Compare costs with the water heating systems tool
• Types of water heating systems
• Smart homes - efficient use of water

Considering solar hot water? Find out more about renewable energy.

For existing water cylinders, wraps are one of the cheapest ways to reduce heat loss and avoid paying extra in energy bills.

The Sustainability Trust can cover 90-100% of insulation costs for eligible households, as part of the Government’s Warmer Kiwi Homes programme.

Eligible homes with sufficient insulation can also receive heat pumps at a 10% cost to the owner. Eligible homes will be owner-occupiers on a community services card or in a low income area.

To apply or check if you're eligible: Sustainability Trust - Warmer Kiwi Homes grant

Some banks offer specific loans* to their members to help make existing homes more energy efficient:

• Westpac Warm Up Loan: 5 year interest free loan up to $10,000 for insulation, heat pumps, double glazing, ventilation, or solar setup.
• ANZ Healthy Home Loan: 4 year interest free loan up to $5,000 for insulation and heat pumps
• Kiwi Bank Sustainable Energy Loan: $2,000 over 4 years toward the cost of an eligible sustainable energy system.

* These details may be subject to change. Contact the bank for more information about these upgrades.