Note: The following information is intended as a general guide only. Seek specialist advice before making any change to your home.
Some homes just feel the heat. Poor air flow, high exposure to direct sunlight or lack of insulation are just some common reasons why it feels like your home is cooking you in summer. Luckily there are some things you can do to manage heat depending at what stage you are – building, modifying or even renting your home.
On this page, you'll learn things like:
- Painting a home for all types of weather,
- managing sunlight and heat coming in through windows, and
- ensuring cool, clean air flow throughout the house.
It’s (sometimes) sunny in New Zealand
New Zealand – we’re not world-famous for our scorching hot weather like our trans-tasman neighbours. We aren’t notorious for cold weather either. Instead, our weather is completely all over the place – sometimes within the same day. This means our homes need to be pretty accommodating for a range of weather and temperatures.
A look at the stats shows that most of New Zealand gets at least 2000 hours of sunshine a year. If you live somewhere like Hawke’s Bay, you’ll get well over 2,300 hours with high temperatures and plenty of hot days.
Is your home good in the heat?
The first thing to do before making any changes to your home is review how well it’s doing in the heat to start with. You’ll want to spend time observing the temperatures in different rooms, understanding how much direct sunlight pours in and figure out where heat flows through the house. Safely, get an idea of how hot your exterior cladding is getting, as well as the roof. If you have a vent system, the control panel will often give you an idea of the current roof temperature so you don’t have to get up there on a hot day.
Here are some things to check:
- Is hot sunlight directly coming through the window and feeling like it could cause sunburn?
- Do objects inside the house get hot or melted when in the line of sunlight coming in?
- Does cool air created by a fan or AC system maintain after switching it off? Or does it immediately get hot again?
- Is the air overly humid and dusty?
- Are there clear draft entry/exit points around the home?
- Does cladding on the outside of the house get dangerously hot?
- Is there a lack of shade around the edge of the house?
- Is there faded or sun-damaged paint on the house?
If you answer yes to even just a few of these, it might be time to think about making the home more sun proof.
Building a new home with hot summers in mind
If you're about to start the exciting adventure of building your own home, you have a lot more control over how your home will cope during hot days. When a home is designed, you will want to think about its position, exterior shade, window design and airflow.
Speak with your architect or building about sun considerations in more detail. It may be that your property is situated in a way that requires special design to ensure you don’t lose sunlight but can manage it when it’s too much.
Some key considerations to a new build when it comes to sun management include:
- The cladding material used – what’s practical for your region’s environment and high/low temperatures?
- The roofing material – does it manage heat properly?
- Does the design of the home provide ample shade areas outside?
- Are exterior structures like garden sheds built to stop heating to dangerous temperatures?
- What is the aspect of the home that will enable as much natural light in as possible, while still providing comfortable year-round living?
- Are you going to have double glazing with heat regulation properties? Does the window solution provide outer layer tinting that reduces the intensity of both light and heat coming in during summer?
- Is there a good ventilation system planned? Do all rooms/parts of the house have ample venting?
- Do you have a heat pump/air conditioning unit for efficient and concentrated temperature control? Which rooms in the home will most benefit from this?
- Does the design of the property include eaves and awnings that help to offer shade to the home itself and exterior fixtures?
Answering these questions early in the new build process can save you time, money and frustration later on.
Painting the house? Choose your paint wisely
Before you let your wonderful artistic side take flight on the outside of your home, stop and consider whether the colour you’ve chosen will work from a practical standpoint too. While a dark colour can look quite striking, in an area with frequent hot temperatures, a dark paint will absorb more heat than lighter paint, meaning the outside of your home can get very hot to the touch. And often, a dark paint will fade from sun damage faster than light paint, meaning touch ups or total repaint is needed sooner than normal.
If you are building in an area that doesn’t encounter hot days on end (ahem, Wellington), you might be totally fine with a darker shade of paint. But if you’re expecting some long summers, think carefully about a tone that reflects more, and retains less heat.
Using blinds to control, rather than remove, sunlight
While thermal curtains that help insulate in winter will block out light, you can buy modern blinds that mitigate the heat without shutting out light completely. These blinds are referred to as ‘translucent blinds’ and are also made to give you privacy from the outside world. During summer these blinds are great for keeping the internal environment light and airy while diffusing harsh sunlight.
Another option is venetian blinds – slat-based blinds that give you control over the angle at which light comes via a tilting mechanism. Venetian blinds are popular as you can shut out most light by closing them entirely, or simply tilt the slats to let air and scattered light in.
Insulation and keeping a home cool – why this matters
When you hear about insulation, the conversation is usually around keeping a home warm in winter. But insulation is equally as important for cool air retention and outside heat prevention. Insulation – material within the ceiling, walls and floors of a house – is an excellent way to control your internal temperature. In fact, insulation is actually a requirement for rental properties since 2019 and part of building regulations for new builds. If you’ve got an older home without insulation in parts of the house, it might be time to think about adding these in.
Insulation in the ceiling prevents heat from the roof moving down into the home. It also stops your cooling efforts from escaping – keeping your power bill down in the process. Why go to all that trouble to cool down the home only for most of it to disappear through a poorly insulated ceiling? Combined with good flooring and wall insulation, your home interior will enjoy it’s perfect climate – no matter what’s happening outside.
We cover cooling systems in a separate guide here, but natural airflow is another important part of a comfortable home during hot days. Without air flowing between rooms in your home, you not only deal with hot stuffy conditions, but prevent the opportunity for dust, allergens, mould and pollutants from home activities like cleaning to escape naturally. This can lead to all sorts of problems like respiratory illness. So, make sure your home has plenty of airflow, on top of an installed system.
While during peak hours it may be too hot to have the windows open, you should be airing out the home frequently during the less intense hours of daylight, as well as during periods of light breezes. This will bring fresh air through the house, and push out the dust. Open the doors, windows and garage and let mother nature do its thing.
Other passive cooling solutions include non-mechanical vents to the outside. However, natural airflow needs to not come at the cost of warmth retention during winter.
Shady outdoor spaces
Once the sunlight hits your home, the solution for heat regulation can be more costly than simply preventing so much heat from getting that far. If you are a homeowner with no plans to move any time soon, plant trees in areas that will grow up and scatter sunlight (without blocking it out entirely).
While you’ll probably want a north-facing home primarily to take advantage of the light and warmth, think about some other shadier areas you can use outside such as a secluded courtyard or outdoor table covered by an umbrella or sail. Being too hot is a problem most Kiwis like to have, but you should have a solution sorted before it is an issue.
Do solar panels make sense where you live?
If you are a homeowner in an area that receives lots of sun, think about whether a solar panel system might help bring your grid power consumption down over the long term. Getting solar panels installed is a significant investment however, so make sure you will see the benefits within a timeframe you’re comfortable with.
Renter tips for surviving summer
With approximately 34% of Kiwis renting, the question remains – how do I keep cool in summer if I’m a renter? You’re not able to make changes to the home yourself, but rentals are required to have a baseline level of insulation since the introduction of 2019 Healthy Homes Standards. These standards also cover things like ventilation and moisture. Provided your home is up to the standard (which it should be), you can use a combination of window shade (curtains, blinds), and natural airflow. If you are still struggling to manage the hot weather, speak with your landlord to explore some other options.
Here’s some useful links elsewhere on the web that can help you prepare a home for summer: