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Passive House vs Homestar

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Matthew Cutler-Welsh
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What’s the difference between Passive House and Homestar? There are many different systems out there, all offering slightly different outcomes. 

Passivhaus and Homestar. Which is right for you?

Passive House vs Homestar

If your main objective is warmth, health and low energy bills, this aligns well with the purpose of Passive House (Passivhaus).

Energy, health and comfort are about half of Homestar. The other half is made up of stuff like waste minimisation, selecting non-toxic paints, water efficiency, landscaping and location. 

The Passive House Planning Package (PHPP) used to model a design, is a robust and accurate tool, albeit quite complex. 

Homestar uses a simplified version of BRANZ’s Annual Loss Factor calculator, which you can essentially do for free yourself, but it’s a much simpler model. 

If your core objective is warm and comfort with low running costs, it’s hard to go past PHPP and Passivhaus. I have a few episodes where I’ve spoken to local experts in this field. 

If your objective is overall sustainability, assurance and marketability of the finished product, then Homestar might be a good choice.

If you’d like any introductions of recommendations for designers, consultants and builders, feel free to get in touch.

Comments

7 responses to “Passive House vs Homestar”

  1. Making Houses Perform – Home Style Green

    […] know what it’s like to live in a good home. For nearly five years, they enjoyed living in the Homestar 10, Passive House Plus Certified Ideal House. The Ideal House is now one of the first Passive […]

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  2. 202: Why are architects not learning this? – Home Style Green

    […] sees the performance outcomes of Passive House design as the first threshold. After that, ‘green’ credentials and aesthetics can be added. This is a great approach. Designing with Passive House first means […]

    Reply
  3. Jessica Eyers Avatar
    Jessica Eyers

    yes I think it is important to point out that these two are quite different and not mutually exclusive. Personally I think Homestar should focus on energy and comfort more. Both have a place as design and reference tools.

    Reply
    1. mcutlerwelsh Avatar
      mcutlerwelsh

      Thanks for your comment Jessica. I’m enjoying learning amore about PHPP right now. So many powerful tools out there now, there’s really no excuse for not doing at least some modelling before building.

      Reply
  4. Glenn Murdoch Avatar
    Glenn Murdoch

    One of the other key distinctions is veracity. Passive House has a well researched, verified and proven methodology compared to Homestar which has no visible science to verify its performance. For example, where is the research to show us that ALF provides accurate predictions of building performance?

    Reply
  5. Kara Rosemeier Avatar
    Kara Rosemeier

    Good overview! May I add that while Homestar is a rating system – Passive House is rather a quality assurance scheme, i.e. it is about outcomes for health, comfort and energy, and about predicting these as accurately as possible. But of course the purpose of PHPP is not only that, but also to influence design decisions. To do this in a meaningful way, it’s necessary to have a model that is a good reflection of reality. All models are wrong – but some are useful. PHPP has the physics stripped down to the bare essentials – but it is still rather onerous to use, at least for beginners. The main difficulty in NZ however is getting accurate material data to enter into PHPP. We all know that rubbish in will lead to rubbish out, and for fine-tuning your model, R-values with one decimal are just not good enough. The wiggle room for the second decimal can lead -in Queenstown e.g. for a wall with 200sqm area to a difference in heat loss of about 300kWh/a. You can heat 20sqm in a Passive House with this amount of energy – far too much uncertainty.

    For being able to optimise your design, that is: not paying too much for the outcomes you want to achieve, you need a great deal of certainty. Using PHPP with good input data gets you there. You are quite right to note that
    Passive House is not concerned about anything beyond health, comfort and energy, so rather than either-or, the smart way would be to use both schemes complimentary, don’t you think?

    Reply
    1. mcutlerwelsh Avatar
      mcutlerwelsh

      Good points, thanks Kara and Glenn. Yes, I think there’s a place for both.

      Reply

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