Homestar ratings

What is Homestar?

To achieve a Homestar rating, the design, energy efficiency, property management and innovation criteria of a house is considered. You need to achieve a minimum number of points to reach each threshold.

A Homestar home will not only be a warmer, drier home, it also factors in environmental impact and lifestyle factors. Unlike with the passive house certification, you can cherry-pick where you put the focus to suit your way of life.

The criteria are:

• energy, health and comfort focuses on heating, ventilation and insulation. Energy efficiency is a big part of it and points are awarded for including efficient appliances and lighting. You’ll improve the rating by providing sound insulation in certain rooms (such as the TV room) or choosing glazing that reduces sound transmission.
• water points can be gained with rainwater tanks and low-flow taps and showerheads. To achieve higher ratings, you’ll often need to install greywater recycling.
  

  

• waste incorporates steps for reducing construction waste and also considers the long-term running of the home (this includes simple steps such as compost and recycling bins)
• management assesses security and safety measures (additional points are awarded for including a user guide for the home and an environmental management plan)
• materials awards points for eco-label products and choosing non-toxic and VOC-free materials
• site considers whether a home has vegetable gardens or fruit trees, and has native plants over exotic species
  
• innovation points are awarded where the design has features that aren’t already included in the rating tool, but help reduce the building’s environmental impact (for example, installing an electric car charger).

Homestar and the cost of achieving it

Last year, BRANZ ran the numbers on the costs associated with going for a Homestar rating for 10 different houses in Hobsonville Point, Auckland. There was a 3% to 4% premium to achieve the minimum rating. Getting the top rating would add a quarter to the final build cost.

Benefits of Homestar

The minimum Homestar rating (a six) guarantees a home that’s warmer, drier and healthier than a similar one just built to code. It’ll also use less power and water, an important consideration if your water is metered.

As you progress through the ratings, the thermal performance of the house will improve along with increasing sustainability of the building with features such as greywater recycling (for example, shower water run-off is used to flush the toilets).

The study also calculated the payback period and found it leaned heavily in favour of opting for Homestar on your next build. The payback time for a six rating was only six years. A 10 would take a lot longer (20 years), which isn’t unreasonable if you’re planning on living in your home for the long haul.

The cost increases shown in our table are for keeping an original house design and adapting it to the Homestar level. So, for a level six or seven Homestar qualification, you could get away with no extra investment by specifying a smaller floor area or cutting costs when it comes to the internal fittings. Another option is rolling up your sleeves and doing some DIY, such as painting, and redirecting the money you’d save on tradies towards Homestar improvements.