Heat pump installation in Invercargill

Invercargill has long, cool winters and a heating season that starts early and finishes late. July averages about 10°C by day and 1°C at night, and cold, windy days are common. Many Southland households run heating for much of the year, which makes efficient heating especially valuable.

A well-chosen heat pump can deliver several units of heat for each unit of electricity it uses, which makes it cheaper to run than resistive electric heaters. In Invercargill, the choice of model and correct sizing matter more than in warmer cities, because heating output falls as the outdoor air gets colder.

This page explains how Invercargill's climate affects heat pump choice and what drives installed price. We're contracting installers region by region, and a contracted installer does the electrical and refrigerant work. Until one is in place in Southland, bookings are on a waitlist.

What does Invercargill's climate mean for your heat pump?

Invercargill City is in H1 climate zone 6, the coldest of the six zones in the Building Code's energy efficiency rules. Zone 6 also covers Southland District, Gore, Central Otago and Queenstown-Lakes. For heat pump buyers, it's a signal to size generously and pay attention to cold-weather performance.

Consumer NZ notes that heat pumps find it harder to extract heat as temperatures drop, and units may need to defrost in cold conditions. On frosty Southland mornings, a unit that looked adequate on paper can fall short. Size using the heating capacity at low outdoor temperatures and look at models intended for cold climates.

Wind is also a factor. Invercargill is exposed to strong westerlies, which increase heat loss from houses and can affect an outdoor unit placed on an exposed wall. A sheltered position, raised clear of the ground so defrost water drains, works best.

What sort of houses are we fitting them to?

Invercargill has many older weatherboard and brick homes built from the early 1900s to the 1970s, in suburbs such as Gladstone, Windsor, Georgetown and Appleby. Many were built with little insulation. Upgrading ceiling and underfloor insulation before installing a heat pump reduces the capacity needed and lowers running costs.

Newer homes in areas such as Otatara, Waikiwi and Rosedale are generally warmer and suit a ducted system or high-wall units sized to the open-plan living area. Multi-split systems are a practical option for older homes where bedrooms are well away from the lounge.

What affects the price in Invercargill?

Prices follow national ranges. Invercargill's flat streets keep most installs straightforward, but brick walls, long pipe runs and switchboard upgrades add cost. Because cold-climate performance matters here, the model you choose may cost a little more than the cheapest option for the same nominal size.

For towns outside the city, such as Winton, Riverton or Bluff, any travel charge should be listed separately.

Which parts of Invercargill do we cover?

What do the Invercargill City Council rules say?

A standard heat pump install on an Invercargill house generally doesn't need building consent, but a licensed electrical worker must connect and certify the electrical work. Invercargill City Council's district plan includes noise rules, so avoid mounting the outdoor unit right beside a neighbour's bedroom and check that the location will comply.

Landlords must meet the Healthy Homes heating standard in the main living room. Because Invercargill is cold, the required minimum capacity can be higher than in northern cities, so use the Tenancy Services Heating Assessment Tool before booking.

Local tips

• Compare each model's heating output at low outdoor temperatures side by side.
• Mount the outdoor unit in a sheltered spot, raised off the ground for drainage.
• Insulate the ceiling and underfloor first; in older Invercargill homes it can shrink the heat pump you need.
• Consider a multi-split or ducted system if bedrooms are cold and far from the lounge.
• Keep filters clean through the long heating season to maintain efficiency.