Is Passivhaus Certification Worth It?

The UK is on the verge of a housing crisis. We need approximately 250,000 homes per year, and the current housing stock is sub-standard in design and energy performance. Heating and powering homes also account for over 20% of all greenhouse gas emissions in the UK. This needs to change.

In the endless pursuit of low-energy living, Passivhaus has emerged as the gold standard for the seasoned self-build industry. The Passivhaus standard is a tried & tested solution that prioritises energy savings, but more importantly, the well-being of the occupants and the planet.

Despite the increasing popularity, self-builders are still asking themselves – ‘Is achieving Passivhaus certification worth it?’ In this article, we’ll break down the certification process, and why you should consider it.

WHAT IS PASSIVHAUS CERTIFICATION?

Passivhaus Certification is a quality assurance programme that ensures your building has been built to the Passivhaus standard, meaning the home prioritises comfortability, affordability, and energy efficiency. Passive House Certification is available for buildings, building components and also professionals.

“For building certification, planning execution is checked carefully and comprehensively. Other documentation relating to the construction such as the airtightness test complete the quality assurance process. A certificate is only issued if the exactly defined criteria have been met without exception.”

- Passive House Institute Website

The Passivhaus standard is founded on the principle of ultra-energy efficiency. Buildings designed to meet this standard prioritise minimising the need for traditional heating and cooling systems through superior insulation, airtightness, and advanced building techniques.

To achieve Passivhaus certification, a building must adhere to strict performance criteria, ensuring that it meets specific energy consumption, airtightness, and thermal comfort standards. These standards are achieved through independent quality testing. This rigorous approach guarantees a high level of sustainability and occupant well-being.

BENEFITS OF PASSIVHAUS CERTIFICATION

The Passivhaus Trust categorises the benefits into 6 groups. Here are the most relevant to self-builders.

Building Performance
Combatting the Climate Emergency
Health & Wellbeing of Occupants
Financial Benefits
Social & Community

Building Performance

Passivhaus certification and optimised building performance go hand in hand. Passivhaus buildings have a low energy demand and are built with effective and healthy ventilation, optimising the comfort of the occupants.

Passivhaus buildings are resilient, comfortable, and built for long-term satisfaction. The focus on performance reduces the costs of future maintenance, too.

Combatting the Climate Emergency

By significantly lowering energy consumption, Passivhaus buildings contribute to a reduction in greenhouse gas emissions and overall environmental impact. This aligns with global efforts to mitigate climate change and supports sustainable building practices. Perfect for a country striving for net zero.

Health & Wellbeing of Occupants

Homes built to Passivhaus standards bring various health benefits to their occupants, both human and animal alike. Passivhaus homes have been proven to be warm and comfortable throughout the year, which lowers the risk of health problems.

The improved ventilation leads to improvements in air quality. This not only contributes to well-being but also addresses issues like condensation and mould growth. To ascertain this level of quality air within your home, the MVHR system is your best option.

Financial Benefits

The financial benefits of a Passivhaus come in a few factors. The first is a decrease in your energy bills. It is estimated that a Passivhaus can deliver a 30% reduction in your running costs to that of a new build. This is due to the efficiency of the heating system and the retention of generated heat.

RICS suggests that the reduced energy bills and running costs add to the overall valuation of the property. By reducing the likelihood of building defects and health and safety issues, your building becomes easier to market if it comes to selling.

Social & Community

By building a Passivhaus, you have taken the first step in improving the local community. All the aforementioned benefits contribute to the health, well-being, and longevity of the surrounding environment.

Becoming more environmentally conscious is not just a trend, but a requirement. By achieving the Passivhaus standard you are becoming a leader in sustainable housing, and those who surround you will see this.

THE CERTIFICATION PROCESS

Here’s how you should approach the certification process:

Make the Decision Early

If you’re looking to certify your self-build, you should notify your team as early as you can, ideally before the design process has started. Early decisions on performance criteria are vital to allow efficient design at these early stages.

For example, design from the outset with construction in mind allows you to achieve efficiencies within the design and save you additional expenses on excessive engineering & material wastage.

These could include modern construction methods such as SIPs or ICF as these methods achieve a great thermal performance, and are effective in limiting thermal bridging and providing an airtight building envelope.

Engaging with a team experienced in Passivhaus design is key. This includes not only Architects who specialise in low-energy dwellings but all key designers affecting the house design involved in the project, such as a Structural Engineer.

A team skilled in low-energy construction would also be able to provide detailing to aid the limiting of heat losses through the fabric.

Engage a Certifier

As well as assembling your skilled team, you will need to engage a third-party accredited Passive House Certifier, who will use the Passivhaus planning package (PHPP) tool from the outset.

Using the PHPP spreadsheet to calculate the design performance is a main part of the Passive House Certification process. This is used to ensure your design meets the stringent Passivhaus criteria and provides you with a calculated energy balance and annual demands.

The PHPP allows your Passive House designer to test the design against your performance criteria. Even if you are quite far off in meeting the PH targets, it will allow you to assess the design and specification to optimise the building performance, and help in deciding what improvements are worth investing in.

Keep The Passivhaus Principles Throughout Construction

During the process, your Passive House Designer/Consultant will be liaising with the design team and independent Certifier to collate all the information, update PHPP calculations and feedback to the Certifier.

It would also be important to schedule necessary air testing (required by Building Control and for Passivhaus Certification) in key stages of construction, so that the airtight envelope can be easily accessed for any rectification. Your team, if chosen wisely, will guide you through this process.

It is this quality assurance check that is invaluable if you are aiming to achieve a low-energy build and Passivhaus certification.

After your house is certified, you’ll be gifted with a Passive House Institute Certificate and a supplementary booklet containing documentation of the energy balance calculations and all relevant characteristic values of the building. You’ll even get a lovely little wall plaque

WHAT ARE THE COSTS?

The costs associated with designing a Passivhaus come from a combination of design fees, certification fees and specialised construction.

The fees towards Passivhaus specialists are completely dependent on the scope and scale of the project. For a small & simple dwelling, the fees would be approximately £8000. The construction costs are generally between 4% - 8% higher than a traditional build due to the added energy specifications.

Despite these extra costs, a Passivhaus will bring financial benefits that are higher than the initial costs in the long term. A Passivhaus is a Nearly Zero-Energy Building, meaning it has a very high-energy performance, while using a much lower amount of energy. This will help bring down those ever-rising energy bills.

PASSIVHAUS CERTIFICATION AT AC ARCHITECTS

At AC Architects, the cost of a preliminary PHPP service along with a consultation service will depend on the size of the proposed building. For example, a simple shape 3/4 bedroom 2-storey 170sqm house PHPP assessment and reporting would cost around £1650 excluding VAT.

This limited service allows for a preliminary assessment of the design against the PH criteria. If the design meets the criteria and you wish to progress certification, a full passive house consultancy fee and certification fee will be applicable. For a customised fee proposal for PH consultancy, please enquire here.

We believe that by pursuing Passivhaus certification, you are not only investing in your immediate lifestyle but also securing long-term benefits for both your finances and the environment.

The Passivhaus standard aligns with the growing global focus on environmental sustainability. The UK government’s Net Zero strategy is a good example, which was put in place to reduce the overall emissions our homes produce. Another recent example is the New Build Heat Standard introduced by the Scottish Government, which will prohibit the use of direct emission heating systems in new homes.

The success of a Passivhaus relies on proper design, construction, and maintenance. With the standard increasing in popularity in the self-build community, we advise making that initial investment, as we believe it is the key to a better way of building and living.