1. Why Are We Building a Passive House Warehouse?

The Starting Point

Closure of Westaflex

Sadly, Melbourne-based HVAC manufacturer Westaflex/Uniflex closed its doors earlier this year after 49 years in business. This was a big blow for many businesses and homeowners, as no other manufacturer in the HVAC industry makes products anywhere near the quality of those made by Westaflex.

Since we started our business over 12 years ago, we've had one core value: quality products before anything else. If we wouldn't use it in our own home, it's not good enough to sell to our customers!

Our Existing Warehouse: Stock Issues

We've been happy in our current warehouse until now. It's an 84m² warehouse with a comfortable office on the mezzanine level upstairs. We installed a Zehnder ComfoAir Q350 ventilation system for demonstration purposes upstairs in our office.

Not too many years ago we operated out of a home office and garage, so 84m² was perfect for us. But this assumed we had regular deliveries from our suppliers! We dealt with the closure of Westaflex by stocking up and hoarding as much of their existing stock as possible (and they were kind enough to manufacture us large quantities of further stock in the weeks leading up to their closure). But this meant we spilled out of Unit 8 and started renting Unit 7 next door.. and then we spilled out of Unit 7 and into Unit 15 in the new Frankland Street development behind us! Fun fact - Google satellite imagery even has bags and bags of Westaflex fittings filling our carpark spaces while we're trying to fit them all in!

We Need a New Warehouse

Not surprisingly, we decided it was time to buy a second warehouse and move the bulk of our operations into the new premises (we still plan to manufacture out of Unit 8). Our new warehouse is just like our old warehouse - a mix of prefab concrete and non-thermally broken steel (it couldn't be much worse for Passive House) - only bigger. It's a 200m² warehouse space with a matching mezzanine level upstairs.

Envirotecture

We originally thought it would be fun to build a more Zehnder appropriate space for our office upstairs. Our ComfoAir Q350 does exceptionally well in Unit 8 in far from ideal conditions. The original concept was simply to better insulate the roof space between the existing structure and our to-be-constructed office ceiling, so that the uninsulated Zehnder ducts could more accurately demonstrate the system's performance.

After talking to a local Passive House builder, we reached out to Andy Marlow from Envirotecture for help in the design and process. Andy very quickly changed our office layout (he did a million times better than us) and set about designing our external walls and ceiling space.

Should We Get Certified?

Andy's concept inspired us. Given we like to do things well, the project grew from our simple idea to something much bigger, and possibly close to being certifiable. Andy very kindly PHPP modelled the office and we were correct - we weren't far off, so why not go a little further!

We're still debating whether to aim for EnerPHit (since the project is technically a retrofit) or to try for full Passive House Certification. We're firm believers in airtightness, so either way we hope to be well below the Passive House requirement of 0.6 air changes per hour at 50 pascals 'ACH50'.

For our warm-temperate climate, EnerPHit certification requires less than 1 ACH50 and a max heating demand of 20 kilowatt hours per m² per annum 'kWh/(m²a)'.

In contrast, Passive House certification requires less than 0.6 ACH50 and a max heating demand of 15 kWh/(m²a). Given we're aiming for below 0.6 ACH50 anyway, the actual differences in construction may not be very much.

How Are We Getting There

We figured this would be a great learning experience to tackle ourselves. We put our in-house team of carpenters through the Passive House Tradesperson course earlier this year, so everyone is excited to do something new!

The biggest issues we have are that there's steel everywhere and minimal solar gain. We're having to heavily insulate to try and combat this.

Ventilation

We have a Zehnder ComfoAir Q600 HRV ventilation system - complete with app control, new RapidLock connectors, DN200 ComfoPipe and CO2 sensors - ready to go. Read our previous blog on HRV vs ERV cores if you're wondering why we chose an HRV over an ERV core.

The Q600 is a much bigger system than our 200m² office space needs, so it will be running at reduced speeds for optimal ventilation. We chose a Q600 specifically, because this is where the whole concept started - we wanted a more suitable office space to install a centralised ventilation system for demonstrations. We already have a Q350 close by in our current office, so we wanted a larger model to demonstrate because the most common question we get asked is "how noisy are they?".

Windows and Doors

We're building a sealed office space on the mezzanine floor within the existing structure of our warehouse. Strata requirements prevent us from replacing the external windows, and we'd run into thermal bridging issues with the prefab concrete frame anyway if we did. So our external airtight envelope will be within the existing structure, containing windows and doors looking out on the current fixtures.

Having previously used Döpfner triple glazed windows from LAROS Technologies in our own home, we understand the importance of good windows! Time constraints prevented us from using imported windows this time around, so we needed to go with something locally made. We chose Energeto Neo windows and doors from Aluplast, which are being locally made and supplied by Kinzel Industries.

Thermal Envelope

External Walls

We're using a 90mm frame, set back from the prefab concrete walls, and insulated with Knauf Earthwool R2.7 Sound Shield Plus batts. We're using SOLITEX EXTASANA® and TESCON EXTORA® on the outside, but since we can't access behind the frames we're having to build in sections and seal everything with ORCON® Classic as we go.

On the inside we're using INTELLO® PLUS and TESCON® VANA for our airtight membrane, together with a 42mm service cavity and 40mm Bradford Supertel industrial blanket.

Ceiling

The current ceiling consists of anti-con blanket, steel and more steel. To combat this we're using Knauf Earthwool R5.0 Ceiling Insulation together with 50/100mm PIR board (we're still working out the effect of 50mm vs 100mm PIR board on EnerPHit vs Passive House certification). To try and get below 0.6 ACH50 we're covering this with INTELLO® PLUS to allow a clean connection with our external walls.

Floor

The current floor has even more steel in it than the ceiling. Again we're using Knauf Earthwool R5.0 Ceiling Insulation together with 50/100mm PIR board (we're still working out the effect of 50mm vs 100mm PIR board on EnerPHit vs Passive House certification). We've taped and sealed all the joints in the current mezzanine floor, but before we install floor coverings, if we have to for airtightness we'll cover it with SOLITEX EXTASANA ADHERO^®.

So Why Passive?

We've been doing this for a long time now, so we're all too familiar with the norm: Australia as a whole doesn't get ventilation. The National Construction Code 'NCC' 2022 finally recognises the importance of ventilation for buildings with less than 5 ACH50, however we've previously written about how it falls far short of what is required for healthy indoor living environments.

Since we started this business, we've only ever sold products we believe in and use ourselves. We believe airtightness and improving our building practices are fundamental in a world of increasing climate unpredictability and rising energy costs. We have long considered HRV ventilation essential in a home and have been installing them now for over a decade. Our preferred options are:

• the DVS EC Reclaim Connect system for retrofitting into typical Australian homes;
• the LUNOS range of decentralised ventilation products for retrofitting into newer builds with limited access; and
• the Zehnder ComfoAir centralised range for new constructions where ventilation has been allowed for at the design stage.

We see only benefits to our Passive House Warehouse: it encapsulates all of our beliefs in what we do in one building; we get a great space for demonstrating our products and explaining the design requirements needed for proper installation; and we get a comfortable and energy efficient office to enjoy year round!

Next Steps

We're excited to do something different and tackle this ourselves. We're going to blog each step of the process along the way. Follow us on Instagram for regular updates.