Space Heating & Cooling

Introduction

Space heating and cooling is one of the largest energy uses in the average New Zealand household, accounting for approximately 30% of an average home’s energy use (excluding vehicles). This makes it the biggest user of energy ‘inside’ the home, although this varies based on climate, with colder regions in the south or central North Island spending an even greater share of their energy bills on heating their homes. Space cooling in New Zealand is less common due to our temperate climate and typically requires significantly less energy than space heating, meaning warmer regions spend less on heating and cooling. The good news is that the same efficient appliance can be used to both heat and cool your home: the heat pump. Alongside water heaters, space heaters are typically one of the biggest users of gas in a home, making it a key household appliance to electrify for health benefits, cost reductions and emissions savings. 

Space Heating

Space heaters vary greatly in size, fuel source and technology, but in general the most efficient way to heat your home is with a heat pump. 

Why choose a heat pump?

• They use less energy: Heat pumps are 3 to 4 times more efficient than gas heaters, and 2 to 3 times more efficient than standard electric resistance heaters, such as oil-column heaters/fan heaters/radiant-electric panel heaters.
• They’re cheaper to run: Switching from inefficient heating systems that run on gas, oil, or traditional electric resistance can save households up to $1,000 per year. Heat pumps deliver more than three times lower energy bills than gas heating. If timed with rooftop solar production (for instance pre-heating a home during the day), running costs can be as low as, on average, $183 a year.
• They’re healthier in your home. As highlighted by many leading health organisations, gas heaters and stoves emit noxious gases such as carbon monoxide, methane, nitrogen dioxide and formaldehyde, impacting the health of residents. These toxins are especially harmful if the heater is unflued. 
• They’re better for our climate. Heat pumps deliver ten times lower emissions than gas heating. 
• Flexible: Most models include timers so you can plan when it’s in use, for example, running your heat pump when your solar is generating energy. They can also be used for heating and cooling.

What to consider

Heat pumps are either ductless split systems or ducted systems. 

Split System Heat Pump (ductless). These are a lower cost yet still very efficient option. The term ‘split’ means the two coils are split, with one indoors and the other outdoors. They are connected together by a refrigerant line that passes through the wall. The outdoor unit is about the size of a suitcase. You might have multiple units in different rooms to create zones with multiple individual outdoor units. These systems are mounted on indoor walls. 

If you want multiple indoor units but only one outdoor unit, the multi-head system fits this bill. However they are less efficient than split systems and the outdoor unit is larger.

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Ducted Central Heat Pump. This is a system that uses ducts (generally in the ceiling) to distribute cooled or warmed air. The system has both an inside and outside unit. If your home already has existing ducts (perhaps for outdoor central air conditioning or central ducted gas heating), be sure to check with an installer to see whether these ducts are suitable for a heat pump. Ducted central heat pumps are more expensive and less efficient to run than split systems. 

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Space Cooling

On average, space cooling technology in New Zealand requires significantly less energy than space heating and our relatively temperate climate means it isn’t used as much as in other countries. Using shading, plants, blinds and other passive ways to cool a home are incredibly important, but with temperatures set to rise, many of us may need air conditioners. Our current methods of space cooling are relatively efficient and are already nearly all electric. For these reasons we can leave them as they are in an electrified world, as long as we generate that electricity with renewables, and our air-cons will still get the cost benefits from cheaper solar electricity available in an electrified home. If you have solar but not a battery, it’s a good idea to set timers to pre-cool homes during daytime solar production to reduce the load in the evening.

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Government Assistance

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• Warmer Kiwi Homes. Eligible homes can get up to 80% of the cost of an approved heat pump installed. Heater grants are capped at $3000 including GST. Check if you’re eligible. 

Rebates current as of May 2024. 

Renters

Renters make up around one third of New Zealand households, and are left behind on reaping the full benefits of electric efficient homes. Rewiring Aotearoa, and other organisations, are advocating for better renters rights to rectify this, but fixing the finance so that these technologies are available to everyone and providing incentives to landlords to electrify their properties so tenants benefit is crucial. Whether you’re a renter or not, write to your MP and demand access to finance for electrification - and more incentives!

In the meantime, renters could choose to purchase a window unit or portable heatpump or present information to their landlord to make the case for a heat pump such as government rebates available, the requirement that gas equipment needs to be professionally monitored or the health impacts of gas appliances. To minimise heating and cooling costs, renters could also seal up draughts, purchase temporary window glazing, install external shading such as plants, shade cloths or blinds and close curtains and doors. 

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FAQ