VIDEO: Architect Paul McNally has total belief in the passive house system

Kya deLongchamps talks to Paul McNally, a Cork architect who’s just won an RIAI Annual Award.

VIDEO: Architect Paul McNally has total belief in the passive house system

Despite the ambitious changes contained in Part L of the building regulations, in terms of energy efficiency, there’s simply no better quality standard of building on offer than passive house certification (PH).

Earlier this year, Dún Laoghaire-Rathdown became the first local authority in Ireland to include an amendment to their county development to encourage a low energy/passive house standard.

What’s on offer is a technically superb level of build, and the results in terms of running costs and crucially— comfort, are astonishing.

A standard sized home to PH standard, even with architectural flourishes, can be heated, cooled, and ventilated for as little as €150 per annum, generally with little use of any conventional means.

The capital cost to go PH or even to renovate to the less exacting Enerphit standard, can command a marked premium of at least 10%.

However, this differential is closing, as essential PH elements such as ventilations systems, insulation and glazing to PH standard are being sourced not in Austria and Germany, but here at home.

Architect Paul McNally, flushed from his win at the RIAI Irish Architectural Awards for Best Sustainable Project, has total belief in the passive house system.

“Houses built to the current Part L standard in the building regulations will be warmer than one built six years ago, and that house should be airtight.

However, that house is 4-5 times leakier in terms of air tightness than a certified passive house.’”

I made a visit to a very special apartment in Clonmel, County Tipperary, Quirkes at 53 O’Connell Street before it won the award last week, because it’s only the third non-residential building in Ireland certified to Passive House standard.

This month it was also one of the final three projects nominated for Best Retail Project at the 2015 Irish Construction Industry Awards.

The entire building is finished with an honest façade of pale grey render. It’s upright but not pinched, with a classical rhythm of windows over the two upper floors.

The certified passive apartment overhead extends from the pharmacy, which takes a sophisticated square bite from front elevation.

The fresh sandy outside surface, I discover is a specialist render, an essential element finishing the insulated outer leaf. I just want to stroke it.

The living space on the first of two floors is split-level, and marries the long south/ north reach of the building — even the east side channels blessed oceans of light distilled from the lane.

“Passive houses really require a southern orientation to make them work, otherwise, there’s little choice but to overcompensate with insulation.

“We needed as much passive solar gain as possible with the building joined on one side and 2 metres from the wall of the other. We don’t want a passive building to have its architecture bullied by practical demands.”

There are several myths surrounding passive buildings, Paul explains:

“Windows can be opened, and if you want the rooms cooler, the thermostat can be set to whatever suits. Naturally in winter, opening windows is not ideal.

With MVHR (Mechanical Ventilation and Heat Recovery), you can keep the windows shut and still enjoy refreshing clean, filtered air, wicked of humidity.”

Triple glazed, aluminium clad units by Munster Joinery free of thermal bridging, deliver a warm window. ‘Three panes of glass means sufficient quiet to live in even a busy town centre like Clonmel, in relative silence.”

Upstairs in the first of two bedrooms, roof-lights by Fakro hold quadruple glazed units.

Three, low upright windows by Munster Joinery frame distant mountain views and the master bedroom features a dropped ceiling with striking architectural voids that gather more light to this north facing room, but set the ceiling at a pleasing float.

The en-suite window allows us to step up on the sill and out in 18th century style to a terrace.

A secret landscape of sharply pitched slate, scullery windows, St Mary’s Church, and a girdle of mountains, make this a view for the soul, protected on all sides by the old walled town.

The wall thickness in the apartment is equally impressive.

“Outside there’s graphite enhanced expanded polystyrene bead finished with a self coloured render. The cavity is pumped bead, and on the inside leaf there’s mineral wool. Passive houses are highly technical, and a sealed envelope is crucial,” Paul explains.

“External insulation wraps around and meets the window. The window is positioned in line with the insulation in the cavity, not lined up with the block-work as in a traditional build.”

A step from the dining area is the Plant Room, containing the heart of every passive build - the MVHR.

Its wall hung and about the size of a 50cm kitchen base unit. There’s the soft hum of perhaps a very good German refrigerator.

Water from the solar panels comes into the unit and preheats the water supply.

An electric heat pump recovers heat from the air in the ventilation system returning it as needed. Baffles around the apartment ensure just about silent running.

“Part of my practise is to create a log of the building’s performance in use. I track internal temperature and humidity, and exterior temp and humidity.”

The resulting graphs, show a very steady indoor temperature of around 20C (+/- 2°C familiar with PH standards).

“Part L is getting towards zero energy”, Paul concedes, “but only incrementally. Wolfgang Feist, founder of the Passivhaus Institut, put down comfort and quality as the end game, whereas Part L is only taking baby-steps towards revolutionising the building industry.”

Paul McNally The PassivHaus Architecture Company. www.passivhausarch.com

Contractor: O’Gorman Construction (Ardfinnan) Ltd. For a full exploration of Passive House go to www.seai.ie

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