Passive house case study brochure - Paul McAlister · PDF fileWorking with the leaders in sustainable design Paul McAlister Architects have been practicing for over 11 years; forging

Paul McAlister Architects Limited. The Barn Studio, 64a Drumnacanvy Road, Portadown, Co. Armagh, BT63 5LY.

T 028 3835 5111E [email protected] www. pmcarchitects.com

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Passive house case study brochure

Working with the leaders in sustainable design

Paul McAlister Architects have been practicing for over 11 years; forging a reputation at the forefront of sustainable design.

The Practice’s primary focus is on the delivery of high quality, environmentally responsible architecture for clients who appreciate the benefits of top quality design and sustainably built environments. The practice centres on having the ability to offer sustainable expertise; this has promoted the continual development of the team’s skills and knowledge. In pursuit of these specialist abilities, Paul McAlister, undertook training in Passivhaus design in 2010. He is now the first Architect in Northern Ireland to become a ‘Certified European Passive House Designer’ which means he can apply a unique knowledge to environmentally friendly architecture projects.

The team continues to invest in training and research in order to provide bespoke services to both private and public sectors clients. Paul McAlister Architects have completed the design of one of the first passive houses in Northern Ireland, which has now been built.

The practice has also recently won an open tender for the provision of architectural services for development of the new CREST Centre for South West College Enniskillen. This project is one of the most sustainable projects in Ireland and will be the first commercial building in Northern Ireland that will achieve Passivhaus Certification.

The range of specialist sustainable services offered at Paul McAlister Architects include -

• Certified Passivhaus design• PHPP (Passivhaus Planning Package) calculations• Thermal bridging calculations• Moisture transport analysis• Site specific climate data• Building physics and analysis• SAP calculations (Energy consumption and C02 emission)• EPC rating (Energy usage and costs)• Education in the energy sector• Supporting sustainable industries

This illustrates one of Northern Ireland’s first passive houses. It combines both high quality architecture and Passivhaus design principles.

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What is Passivhaus design?

A Passivhaus is a building constructed using the principles of passive design – a concept based on minimising heat losses and maximising heat gains, thus enabling the application of simplified building services.

Typically this includes optimising insulation levels with minimal thermal bridges, high thermal performance windows, very low air-leakage through the building envelope, and utilisation of passive solar and internal gains with good indoor air quality maintained by a mechanical ventilation system with highly efficient heat recovery.

In order to achieve these desired criteria innovative construction methods are adopted, resulting in a highly durable built outcome. These criteria also result in a dramatic reduction in space heating requirements, reduced C02 emissions and lower energy consumption.

Passivhaus design has many advantages over conventional construction and design techniques. In this particular case it offers a modern and comfortable dwelling with no cold drafts, no temperature variations from room to room, a quiet internal environment and significantly reduced utility costs.

A certified Passivhaus must be built with meticulous attention to detail according to principles developed by the Passivhaus Institute, and certification can only be achieved through an exacting quality assurance process. Paul McAlister Architects are experienced in tailoring the Passivhaus philosophy to each individual project. Taking into consideration client requirements, site climate, Passivhaus principles and how they are rigorously applied allows the practice to offer a totally inclusive service.

This north facing front elevation illustrates more modest glazing to limit heat loss and timber cladding to add warmth to the crisp white exterior finish.

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First and ground floor plans of the Crawfordsburn Passivhaus design - including the exterior site layout.04

The optimum use of glazing on the southwest side of the house facilitates solar gain and afford the best views from the main living space, dining room and kitchen areas.

A modern interpretation of natural materials results in a crisp new dwelling which fits seamlessly into the rural context.

The zinc cladding illustrates the high specification to which the dwelling has been completed.

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Introducing the future of housing

This individual dwelling, which adopts a Passivhaus design standard, is nestled in rural Northern Irish landscape adjacent to farm buildings. The dwelling form is inspired by tradition local architectural principles, yet is enhanced with a contemporary feel through the application of natural materials and minimalist detailing.

Our clients envisaged a high quality, certified passive dwelling built within the confines of a modest budget. The final dwelling was strongly influenced by Paul McAlister Architects extensive experience of sustainable architecture and Passivhaus design approaches.

Large amounts of glazing on the southwest side of the house not only facilitate passive solar gain to the interior but also afford the best views from the main living space, dining room and kitchen areas. Light also penetrates the double height living room space through two large skylights allowing further illumination.

The rigorous Passivhaus Design approach has been woven into the design from the beginning. This proposal is environmentally responsible and makes use of the following criteria as a design motivator.

• Super insulated walls, floor and roof• Use of a Mechanical Heat Recovery System and ventilation• Passivhaus approved triple glazing• Use of Thermal Mass in passive heating and cooling strategies• South facing glazing maximises thermal gain

Diagram illustrating the dwelling configuration, including strategically positioned glazing, shading, solar panels and the mechanical ventilation heat recovery system

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This exploded diagram illustrates the building systems, including mechanical ventilation, plumbing and domestic hot water. The hot water is heated by means of solar panels in the summer connected to a 300 litre thermal store. The thermal store has an integrated heat pump which economically provides hot water in cooler months.

Future proofing domestic energy needs

The applied Passivhaus approach dramatically reduces the demand for space heating which means the house does not require a conventional central heating system. It is anticipated that the peak space heating demand will be in the order of 14kWh/(m2/a) for the entire house. Compare this to 50kWh/(m2a) for a typical new build dwelling, or even 100kWh/(m2a) for an older dwelling, the saving is evident. The primary heating for the dwelling is provided by a 5kW wood burning stove which will only be required for four months of the year.

The ventilation system will transfer a calculated amount of heat throughout the house with smaller rooms needing no additional heat source due to the delivered temperature of the warm air.

The hot water is heated by means of solar panels in the summer connected to a 300 litre thermal store. The thermal store has an integrated heat pump which economically provides hot water in cooler months.

Efficient building performance

The house is ventilated by a mechanical ventilation system with heat recovery allowing the heat produced within the building to be ‘recovered’ and used to ‘passively’ heat the dwelling. The thermal mass of the building also plays a part in reducing the heat load of the house with large south facing windows capturing the heat of the sun thus adding considerably to the heating efficiency of the dwelling.

The dwelling’s energy performance has been analysed by imputing relevant data into the Passivhaus PHPP software at design stage. This software measures the energy efficiency of the building fabric and allows for ‘passive’ heat gains such as south facing glazing, heat recovered from the ventilation system and the energy given off by the day to day usage of the house. These ‘passive’ heat gains maintain comfortable temperatures within the dwelling.

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Why aim for Passivhaus certification?

In this instance our client opted to have the house fully certified by the German Passivhaus Institute. This costs a little extra in terms of consultancy fees but means that the house will have a quality approved certificate issued by the Passivehaus Institute in Germany. The certification recognises the outstanding performance levels of the dwelling. One of the reasons for attaining these performance criteria is to reduce the utility costs. As mentioned, these are significantly lower than those of a conventional dwelling; consequently we can clearly identify the financial benefits of Passivhaus design.

Optimum performance, delivered in budget and on time.

Completed in April 2013 the project is now Northern Irelands’ second privately owned Certified Passive House and we are delighted that is was constructed on time and with virtually no additional costs during the build. This building is an example of how a technically advanced building may be built within a modest budget and in the same manner as a conventional house.

This section illustrates dwelling U-values (measurement of heat transfer/loss), air permeability and solar gains. Passivhaus design adopts a super efficient building envelope in which the heat gains and losses balance with one another..

This stacked column chart illustrates the heat gains and losses for the passive house, produced by the specialist Passivhaus software. It shows us that the heat losses are balanced by the heat gains in the passive house. In a ‘typical’ house the losses are far greater than the heat gains, meaning that the deficit needs to be fulfilled by heating at additional costs.

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Lifelong value and utility costs

Keeping domestic energy bills under control is a continual battle, with energy suppliers constantly announcing price increases (energy prices have increased by over 30% over the past three years, 17.8% in this year alone). Electricity and home heating oil are typically used to fuel houses in Northern Ireland (85% of households). This innovative passive house employs a variety of techniques to fuel itself.

The dwelling heats itself ‘passively’- utilising heat gains from south facing glazing, heat recovery from the ventilation system and the heat given off by the day to day usage of the house.

While this passive house cost 8.35% more to construct than a ‘typical’ home of the same size its energy costs are significantly lower.

We have carried out exact calculations to compare the running costs of the passive house with those of a conventional home. In the first year of occupation the running costs of the Passivhaus will be £414.62, considerably less than £1391.95 for a conventional dwelling. Taking into consideration the continual energy price increases this margin will increase further, after 10 years the passive house occupants will have regained £15575.97 in saved energy costs. The energy costs for the passive house are actually a minimum of 70% lower.

The difference of the construction cost will be gained back in 10.2 years. The overall building efficiency, interior comfort levels and innovative design ensures that the Passivhaus delivers many advantages over typical construction.

‘We met Paul McAlister 5 years ago when we were thinking of building a passive house. We were always interested in building a house that was comfortable twelve months of the year but without very high fuel bills. This is our first build project and we are delighted with how it has turned out.’ - Helen McGlinchey, Client

The client and the builder, Kevin Mulligan from Baylands Construction, on the first day of dwelling construction

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AECBthe sustainable building association

Paul McAlister Architects Limited. The Barn Studio, 64a Drumnacanvy Road, Portadown, Co. Armagh, BT63 5LY. Tel: 028 3835 5111Email: [email protected]: www. pmcarchitects.com