New Zealand Made

Proudly family owned and locally made

When you choose Altherm you're supporting a New Zealand made product. 

As part of the largest supplier of windows and doors in the country, our commitment to 'all things local' began when APL did - in 1971. For us, it starts with our products which is why everything we manufacture is designed and tested for New Zealand buildings and take into consideration our country's unique landscape and environment. 

We've never been more committed to supporting the growth of our local communities. 

NZ owned and operated

APL began in the heart of the Waikato in 1971, by a local family. Fast forward to today and we're still family-owned and Waikato based and have since built a nationwide network and several respected brands, including Altherm Window Systems. For over 40 years Altherm has been working with architects, designers and homeowners across New Zealand. All Altherm manufacturers are independently owned and operated with local knowledge and relationships.

Designed for NZ

We take huge pride in our track record of supplying window and door solutions for New Zealand home and building owners. Everything we manufacture is designed and tested specifically for New Zealand homes and businesses. Our Centre of Innovation houses our dedicated research, development and testing facility where our products are developed for our country's unique landscape, weather and aesthetics.

Part of our commitment to designing for New Zealand is designing and operating in a way that reduces our environmental footprint.

NZ end-to-end

Altherm is a brand of APL, the largest window solutions organisation in New Zealand. Every part of our supply chain has a local connection. Our Waikato based team designs and develops the product ranges. Our aluminium is extruded and surface finished in Hamilton. It’s then distributed nationwide to our independently owned manufacturers who fabricate and install the windows and doors into kiwi homes.

Supporting jobs

APL is a vertically integrated business which ensures our products are of the highest quality, delivered on time and help keep jobs in New Zealand. The ability to carry out most steps and produce many components in the operation and keeps business in our own backyard. 

Together with our manufacturers, we work closely with architects, builders and suppliers in the New Zealand building industry, helping to provide jobs to thousands of kiwis in towns and cities across the country.


While our headquarters are in the Waikato, our extensive network of branches, staff and manufacturers spreads across Aotearoa.

Kiwis have been building homes with Altherm windows and doors for over 40 years. Explore some of these homes through our stories, videos, podcasts and galleries for inspiration.


Our independently owned manufacturers are based in towns and cities nationwide. They have a wealth of experience and because of their involvement in manufacturing and installation on a daily basis, their advice is highly practical.