Care and maintenance

Altherm products meet all statutory warranty requirements and are fully tested to ensure compliance with the New Zealand Building Code. There are some simple things you can do to help retain their appeal for many years to come.

  • After house construction is completed make sure any builder’s debris or dust is cleaned from the inside of sills to ensure drainage holes are not blocked. This is especially important for doorways that may have been in regular use during construction
  • Cleaning once every three months is recommended for windows and doors. In coastal or industrial environments more frequent washing will be required
  • We recommend cleaning with a soft brush with warm water and some mild household detergent. Rinse with fresh water
  • Do not use abrasive steel wool, scrapers, scouring liquids or aggressive solvents or thinners. These are likely to damage the surface finish
  • The cleaning cycle should include the removal of build-up in door tracks to ensure the maintenance of drainage paths. 

Cleaning once every three months is recommended for windows and doors

Hardware care

Regular maintenance of hardware is recommended.

Powdercoated hardware should be cleaned regularly with a wet sponge or soft brush, warm water and a mild detergent and rinsed with fresh water. Plated product should be cleaned with a wet sponge without the use of detergent, as it can damage plating.


Stainless steel hardware needs to be cleaned regularly and care needs to be taken when rust spots occur. Even the highest grades of stainless steel can develop rust spots and these can be removed with a mildly abrasive cleaner and rinsed with fresh water. In cases of heavy corrosion a Scotch-Brite™ hand pad can be used. Specialised 3M® Stainless Steel Cleaner and Polish is also available as an alternative cleaning compound.

Regularly clean hardware with warm water and a soft brush

Take care with glass

Glass is a very delicate product that can be easily damaged.

Care is needed to ensure that scratching does not occur. Only detergents and cleaning solutions which are recommended for glass should be used. Begin cleaning by soaking the glass to loosen dirt. Then using a mild, non-abrasive solution, uniformly apply to the glass surfaces. Ensure that the solution is removed by rinsing with water as cleaning residue can permanently mark glass.

Soak the glass first so dirt lifts easier

Condensation and Heating Efficiency

On average, we spend around 90% of our day indoors so the quality of the air in our homes, work and schools impacts our health and comfort and the efficiency of heating systems. Our most basic day-to-day activities create moisture in our homes which appears as condensation when it meets a cold surface and is much harder to heat than fresh air.

Thorough ventilation is the best way to keep our indoor air quality high and flush out moisture. We've developed a number of passive ventilation products which can work with your lifestyle and bring less-humid fresh air in to help the efficiency of your heating systems.