Wondering what other tools you can use to model your home’s performance, beyond the compliance check required in your area?

Discover what PHPP (Passive House Planning Package) can add before you commit to construction of your renovation or new build.

Learn how to layer multiple modelling approaches during design, so the decisions you make about insulation, windows, shading and airtightness are backed by data, not guesswork.

Listen to the episode now.

Hello! This is Episode 416, and Way #16 of the ‘44 Ways to Create Your Sustainable Home’ series here on the podcast. We’re continuing through Section Four: Modelling and Measuring Your Sustainability.

Way #16 is: Use Other Options to Model Your Design Before You Build.

In the last episode, I talked about NatHERS energy modelling and why it can be so valuable as a design tool rather than simply a late-stage compliance exercise.

In this episode, I want to explore what else is available to you, especially where you’re aiming for a high performance home.

Think of this as a set of tools that help you understand how your home will perform before you build it, so you can make better decisions with your money while change is still cheap.

Passive House is sometimes spoken about as if it’s what you do instead of NatHERS. That either you’re a NatHERS person or you’re a Passive House person. That framing is, I think, unhelpful.

Back in Episode 263, energy efficiency assessor and Passive House Certified Consultant Melanie Lupis put it this way: it’s a spectrum. If you can budget for Passive House, fantastic. But that doesn’t mean NatHERS is terrible. When NatHERS modelling is used effectively and collaboratively to inform your design approach, you can create a quality home that performs well. You don’t have to leave it up to chance.

What matters is that you’re making considered choices at whatever point on that spectrum you land, rather than just defaulting to the compliance minimum because you weren’t aware of how modelling could factor into your project journey.

There’s a few things I see happen around the topic of Passive House generally, that I want to mention before I dive into telling you about the modelling tool, PHPP.

The first is, you’ll hear Passive House celebrated, often by Passive House professionals, as ‘the best way’ to build the most highly energy efficient and high performance home’… and sometimes ‘the only way’.

The second is, I see people find out about it in their building or renovating journey, and have one of few reactions:

1. They fall in love with it as a way of designing and building, and commit fully to it
2. They like the approach and system, and want to adopt as much of it as they can, but not worry about getting fully certified, as they see it as an extra and potentially unnecessary expense
3. They learn what it might mean financially for their project, and decide it’s out of reach, but then feel like they’re getting a substandard or poorer quality home with a more conventional approach to energy efficiency and high performance design and construction (sidebar: this is not necessarily true)
4. Or they feel something like ‘we want to open windows’ or ‘we want a home that breathes more’ or ‘we want a more organic home’ or some other misconception about the airtightness aspect of Passive House, and dismiss it altogether. This is a misunderstanding of airtightness, which is relevant whatever your project approach is.

Me personally? Well, there are two things I really love about the Passive House approach, that can actually be adopted in ANY project, whether formally Passive House or not.

The first thing I love about the Passive House approach is the as-built verification process.

The second thing I love about the Passive House approach is its modelling with PHPP.

PHPP modelling can be done on any project, and I’ve seen some of our HOME Method members who aren’t planning a Passive House, but are utilising components of its approach, access the PHPP modelling to achieve a more nuanced understanding of their home’s energy consumption and efficiency.

Where NatHERS produces a star rating based on thermal performance against a national benchmark, PHPP is a performance-based method focused on occupant comfort AND home energy use, with occupancy data, thermal bridging, indoor air quality and dehumidification all factored in.

In this Episode, I cover:

• Why NatHERS and Passive House sit on a spectrum, not in competition, and what that means for your project
• What PHPP (Passive House Planning Package) is, and what it can tell you about your home’s performance even if you’re not pursuing Passive House certification
• The key differences between NatHERS and PHPP, including occupancy assumptions, thermal bridging, indoor air quality and dehumidification
• Why airtightness matters even if you plan to open windows regularly, and what a 10ACH assumption in NatHERS actually means
• The Powerhaus app as a bridge between NatHERS and PHPP, including how it works with your existing NatHERS model
• 3D sun path modelling, why not every designer uses it, and why you should ask about it before hiring anyone
• When to use these tools in your project timeline, and how a HOME Method member saved over $100,000 by using modelling to test an assumption about their build

Plus a whole lot more.

LISTEN TO THE EPISODE NOW.

RESOURCES:

Season 08 | Episode 09 with Daniel Kress of Smart Plus Homes >>> What is Passive House (or Passivhaus)?

Season 08 | Episode 10 with David Rhind, Owl Woods Passive House Project >>> The Client who wanted a Passive House

Season 08 | Episode 11 with Talina Edwards, Talina Edwards Architecture >>> The Architect who designed a Passive House

Season 08 | Episode 12 with Luc Plowman, Detail Green >>> The Consultant who tests and measures the Passive House

Season 08 | Episode 13 with Stuart Lee, Craftsmen Quality Builders >>> The Builder constructing Passive House

Season 08 | Episode 14 with Clare Parry, Grun Consulting >>> The Certifier and an Australian Passive House Pioneer

Season 08 | Episode 15 with Cameron Munro, Armadale House >>> The Passive House Renovator

Season 08 | Episode 16 with Frances Cosway, White Pebble Interiors >>> Building a Sustainable Forever Home

Episode 296 with Jessica Allen, Climasure [NCC Series] >>> Air Tightness and Blower Door Tests

Episode 313 >>> Building a Sustainable New Home: Here’s How to Get It Right

Episode 370 with Tatiana >>> Planning Kitchens, Bathrooms and Finance for a Sustainable New Build

Episode 326 with June >>> Building a Home Whilst Living Remotely from the Site

Episode 315 with Powerhaus Engineering >>> Smart Data to Design an Energy Efficient Home

Episode 316 with Powerhaus Engineering >>> Saving $80,000 in a New Build

Episode 263 with Melanie Lupis, Sustainability Certified >>> How to Design and Build an Energy Efficient, Zero Carbon Home

Maxa Design’s blog post on thermal modelling >>> Passive House vs NatHERS star ratings

Leading education, promotion, and support for Certified Passivhaus buildings in Australia >>> Passive House Institute Australia (PHIA)

Excel-based energy modelling tool used to plan and certify Passive House, EnerPHit and PHI Low Energy Buildings >>> Pas­siv­e House Plan­ning Pack­age (PHPP)

Improving energy efficiency and comfort in Australian homes >>> NatHERS, Nationwide House Energy Rating Scheme

A free e-guide to simplifying sustainability across research, planning, design, materials, and building >>> 44 Ways to Create a Sustainable Home

Access the support and guidance you need to be confident and empowered when renovating and building your family home inside my signature online program >>> HOME Method