When passive house specialist Garrett Quinn set out to build a home for his parents in Dungannon, he was confronting a range of challenges. For one thing, he hadn’t built a passive house before. For another, there were few resources north of the border to assist in his drive for better building standards.
To set the bar even higher, he was determined that the house would avoid the passive house design clichés. This would not be a square, compact building with minimalist styling. In fact, the aesthetic would ignore all of that and take its references the Arts and Crafts era houses found in this part of Tyrone. Featuring high, pointed gables with complex junctions and a distributed footprint, it’s about as far from the contemporary German box as you can get.
“I wanted to show that we didn’t need to be simple about things,” says Quinn, “that we could use what was being taught about passive house to be more adventurous. I was confident I could square the circle.”
Quinn used the passive house software, PHPP, to work through the design and discover the right combination of fabrics and techniques to get all of the variables working within passive house thresholds. To compensate for the complexity of the build, he found he had to bulk up the insulation in key areas. “We have a lot more insulation in the building than we said we would at design approval stage, purely because of the irregular shape.” As a result the walls are deep – up to 470mm.
An engineer by profession, Quinn went back to school after the crash and did a postgrad in renewable energies in Jordanstown. It was while working through the green building module that he discovered passive house, and became a convert overnight.
A timber frame was chosen primarily for air tightness purposes. At the time, Quinn felt that timber frame would make it easier to hit the 0.6 ACH passive house requires, though he’s since come round to the idea that masonry builds can perform just as well. The kit also came with ‘Easi-Joists’, a system which makes it easy to thread services through voids, especially ventilation ductwork.
Understanding just how important craftsmanship and professionalism is when aiming for passive standard air tightness, Quinn says he went through three different squads of joiners before he found a team he was confident could deliver the results he needed.
“Every time there was a new trade onsite, I could always tell by the look in his eye whether or not he were going to last the day with me. Some guys were interested, some guys just couldn’t see the point as to what I was aiming to achieve. They were the guys that didn’t get the call back.”
Quinn actually changed over 80% of his team over the course of the project, before settling on a group of tradespeople who were as engaged in achieving higher standards as he was. Because he put so much time into finding the right people, there has been no turnover in that team ever since.
He says: “They’re the ones that stuck around because they understood the value of what I as trying to achieve.”
Quinn ensures that everyone on his team attends regular courses in order to keep their skills fresh. As a member of the northern chapter of the Passive House Association of Ireland, he gets together regularly with other passive house builders and designers in Northern Ireland to share ideas and insights.
“We jump in the car and go down for a class or a talk or whatever’s going on in Dublin or wherever. It’s sore on the pocket, but I believe in it and that’s the only reason I do it.”
As has been said by almost all of the passive house builders interviewed for this series, Quinn also emphasises the importance of constant attendance on site. “It might mean there are staff inefficiencies but it means you’re going to get quality over the line.”
Through a combination of oversight, training and guidance, onsite quality filters down through the build team, allowing them to achieve the exacting standards required by passive house.
That’s not to say things didn’t go wrong. Mark Gribben of Setanta Construction, who provided the timber frame, advised against covering up the air tightness membrane ahead of the first blower door test. Believing he had enough done however, Quinn went ahead and installed the PIR insulation over the membrane, only to discover after the test he should have taken Gribben’s advice.
“I had to take all the insulation off the walls,” he says. “That was the start of the learning curve…All these little pin holes that we had made had to be covered up. It wasn’t a big deal, I lost maybe 5 man days on it, and it was a cheap lesson in the greater scheme of things.”
The second air tightness test recorded an ACH of 0.55, well inside the 0.6 target. “I’m extremely proud of that”, says Quinn, “because we’re talking about something that’s nearly 20 times better than the building standards (in Northern Ireland).”
Just as he wanted to demonstrate that it was possible to make any home passive, he also wanted to show that you didn’t really need obscure materials to do it. “Bar a couple of items,” he says, “we can use the stuff in the local builders’ suppliers; we can use the stuff that’s on the shelf to create a passive house.”
With that aim in mind, Quinn set out to tackle cold bridging. He originally specified foamglass blocks for the footing, but they weren’t readily available. Instead he went with Quinnlite blocks. They worked out perfectly, and have been used on all of Quinn’s subsequent builds.
One other interesting feature of this project was the client’s insistence on installing an Aga range. “It was bought,” says Quinn, “before the foundations were laid.”
Keeping the range within the house’s energy budget gave Quinn another ball to try to keep in the air. It helped that the client opted for an Aga Total Control – an electric version of the iconic range – as opposed to the traditional solid fuel version. “We are able to control how much energy is used, and obviously this affects the primary energy demand, but it’s actually proven to be a great asset in the house. On the coldest days, there is this extra heat source that can be turned on if necessary.”
The clients, who have now been in the house for nearly 18 months, report that temperatures are comfortable and even and air quality is perfect.
In order to minimise the control interface, the house is broken into two zones, upstairs and downstairs, each controlled by a simple, wall-mounted digital stat. If the temperature drops below the set point, a motorised valve releases hot water from the solar array to the ventilation system, which then distributes it wherever it’s needed. A condensing oil boiler provides back up.
“My parents are spending no more than £200 a year on heating and hot water. This has just blown my dad’s mind, because he’s been in the construction industry for 50 years and he had never come across a house that delivered as much for as little.”