Smart Design, Real Savings: How BXG is Cutting Construction Costs Through Homestar Expertise
As building costs continue to climb, developers are under increasing pressure to deliver sustainable housing without blowing the budget. That’s where BXG is making a real difference — not just in compliance, but in cost-effective performance.
Specialising in Homestar assessments and performance modelling, BXG has carved out a reputation for helping developers find smarter, leaner ways to meet New Zealand Green Building Council standards. With in-depth technical knowledge and mastery of the Homestar and energy modelling tools, BXG doesn’t just tick boxes — we rewrite the rules of what’s possible in sustainable design.
A recent 41-home residential development showcases the impact of their work. Initially presented with a design requiring 140mm timber framing, full underslab insulation, and a heat recovery ventilation system to achieve a Homestar 6 rating, the cost outlook was steep. But BXG’s technical team saw an opportunity… By diving deep into the thermal modelling and performance calculations, it was possible to demonstrate that the same Homestar 6 rating could be achieved with 90mm timber framing, a reduced slab insulation spec, and the removal of the full heat recovery ventilation system.
The result? Significant savings — without compromising performance.
“We’re not in the business of over-engineering and box-ticking. Our role is to ensure the design meets Homestar in the most efficient way possible, balancing cost and performance without unnecessary complexity.”
Take timber, for example. The original design specified approximately 1,000 lineal meters of 140mm framing per house, at an estimated $14 per lineal meter. By switching to 90mm framing at just $9 per lineal meter, BXG’s solution cut framing costs by around $5,000 per home — a saving of over $200,000 across the entire development.
Further savings came from reduced slab insulation and the removal of the heat recovery ventilation system, which was deemed unnecessary after recalibrating the thermal envelope. Combined, these changes saved the developer tens of thousands of dollars, while maintaining full compliance with Homestar 6 requirements.
For developers, the message is clear: a high-performance home doesn’t have to come with a high price tag.
“Too often we see projects over-designed because the tools aren’t used to their full potential. That’s where we come in — to challenge assumptions and optimise performance where it counts.”
With a growing portfolio of projects and a track record of unlocking hidden value, BXG is proving that sustainability and affordability can go hand in hand — and that smart compliance is just good business.
If you're planning a project and looking for cost-effective solutions to achieving better environmental outcomes, contact BXG to discuss how they can assist you. Alex@bxg.co.nz