Passive House Design: Warm Temperate

Renovation Collaborative

How do you design a Passive House in Warm Temperate climates like Perth, Adelaide or Sydney?

In today's episode, I continue to investigate the design specifics for each of the four climate zones around Australia, where most of our population lives.

I talk to very experienced Passive House designer Ben Caine, the director of the award-winning practice Leanhaus Architecture in Perth. Ben’s architectural mission is to deliver well-thought-out, mindful, architectural homes to the passive house standard, at less cost than a typical architecturally designed home. Ben explains the Passive House design specifics for Warm Temperate, plus he shares ideas on cost savings and heaps of other information and insights from his years of experience to help you better understand Passive House.

Australian Architects can claim formal CPD hours for these podcasts.

MORE INFORMATION

Find everything you need on the Renovation Collaborative website.

www.renovationcollaborative.com.au

• PODCAST Key points summary, timestamps and resource links
• FREE RESOURCES Transcript edited into clear Q&A.
• CPD Australian architects can find more information on CPD, and
• COURSES Eleven easy to read courses demystifying the entire home design and construction process.

KEY POINT SUMMARY

1. Through his practice, Leanhaus Architecture, Ben delivers well-thought-out, mindful architectural homes to the passive house standard for a lower cost than a typical architecturally designed home. His practice proves that if you are open to finding efficiencies across design and construction, you can have a passive house or high-performance home without the additional cost.

2. Ben generally designs to the Passive House standard without going as far as certification for the simple reason that Passive House certification adds cost. However, it’s essential to note that during the first four years of Leanhaus Architecture, Ben and his team went to great lengths to model, test and optimize every design and understand the exact formula for success. They can now confidently deliver to the passive house standard without the extra cost.

3. The 5 Passive House design components for a Warm temperate climate are as follows:

• Windows are double-glazed and always operable. Windows should enable cross ventilation, purging any excess heat build-up, and connection to the outdoors to enjoy comfortable external temperatures during spring and autumn.
• The fresh air circulation system is an HRV
• Wall insulation can fit within a typical 90mm timber stud framed wall thickness. No under-slab insulation is required, but sometimes slab edges may require insulation.
• Only one layer of external wrapping is required; the vapour-permeable weatherproof membrane on the outside of the home is taped, sealed and made airtight. An additional internal membrane may be used to obtain certainty of airtightness, but it can be avoided in most cases to reduce costs.
• Removing thermal bridges is always essential.

4. Shading is critical, particularly from low-angle sun from the east and west and even from the south in summer. Passive houses retain heat effectively because they are well-insulated and sealed; therefore, the hotter the climate zone, the more shading is required.

5. Reverse cycle air conditioning systems are predominantly used for cooling. The heat load created in the house through cooking, showering, etc. is sufficient for heating. The air-conditioning system size is minimal, at 20 Watts per square metre or less. By contrast, for an ordinary house an air-conditioning contractor would typically provide 60 to 80 Watts per square meter. As an example, Ben has a 6 kW split system for his entire 240m2 house.

6. Australian passive house design is very different from passive house design in the extremely cold climates in Europe. Our sunny, comfortable climate allows us to live with an indoor-outdoor connection. People associate Australian architectural design and modern living with large expanses of glazing, particularly connecting to outdoor living spaces. Passive house design in Australia retains those big expanses of glass and the Australian way of living as much as possible. It maintains people’s expectations of what an Australian house should look like while exceeding expectations about health, comfort and energy efficiency performance.

INTERVIEW QUESTIONS

00:00:00 Introduction

00:04:54 What does your practice name ‘Leanhaus’ mean?

00:08:50 Are most of your projects Certified Passive House or uncertified high performance?

00:12:52 What sort of clients come to you looking for a Passive House / high performance home?

00:15:20 What is the warm temperate Perth climate like?

00:19:10 Are all houses built in Perth double brick construction?

00:22:59 What are the window design requirements?

00:31:10 What are the shading design requirements?

00:37:42 What happens if too much sun gets in and the house gets too hot?

00:41:57 What are the cooling / heating system requirements?

00:47:44 What are the airtightness wrapping requirements?

00:51:18 How do you choose which building wrap to use from the multitude of options?

00:53:10 What are the insulation requirements?

00:54:58 Are there any other considerations?

00:57:11 Can you provide any advice on products and materials suppliers?

01:01:20 In your experience what are the main barriers to Passive House?

01:04:23 How much cost does Passive House add to a project?

01:10:07 In your experience are there any problems with Passive House?

01:14:26 Key Point Summary

IN THE NEXT EPISODE

Next week, you’ll learn how to design a Passive House in a sub-tropical climate like Brisbane.

I talk to very experienced Passive House Designer Tiago Guerreiro, a director of the award-winning design and construction company, H4 Living in Brisbane.

H4 Living have been creating passive houses and high performance homes for over 10 years. Tiago shares the climate design specifics plus heaps of other insights from his years of experience to help you better understand Passive House design.

RESOURCE LINKS

Ben Caine, Leanhaus Architecture www.leanhaus.com.au

International Passive House Association www.passivehouse-international.org/

Certified Components Database www.database.passivehouse.com/en/components/

Australian Passive House Association

www.passivhausassociation.com.au/

GET IN TOUCH

If you've got any comments or questions or there's any topic you'd like to know more about, please send me an email at [e-mail].

www.renovationcollaborative.com.au