Gary Vaynerchuk, the social media superstar and business leader, released a book in 2013 called “Jab, Jab, Jab, Right Hook” (#JJJRH) which uses a Boxing analogy to highlight the best approach to using social media channels. Jabbing is giving value to your followers & community, and the follow up Right Hook is asking for something, whether this be attention or sales. This means at least 75% of your posting on social media should be about giving value and sharing useful information and insights with your followers and community, not asking for attention or for a sale. Everyone appreciates generosity over being repeatedly asked for attention.

What has this got to do with passivhaus? The Passivhaus Standard is most well known as “the world’s leading standard in energy efficient design.” And energy efficiency asks building owners and occupants for something. It asks them to at least modify their behaviour and to pay more attention to the operation of their building. However, energy efficiency is actually only part of passivhaus. People don’t often realise that the Passivhaus Standard is also a rigorous comfort standard that ensures a building is free from draughts, free from cold spots, free from excessive over heating and provided with a constant supply of fresh clean air. And it does so with the minimum amount of energy.

Passivhaus throws an outstanding “Jab, Jab, Jab” of occupant comfort before hitting home with the solid “Right Hook” of energy efficiency.

Passivhaus-Comfort

Jab 1 for Comfort: Draught-free

Architects and designers rarely give much attention to specifically eliminating draughts and as a result most buildings are not draught-free. And it only takes a tiny hole, gap or crack to allow a cold draught to whistle through into a building and cause discomfort. People rarely think about how much discomfort even a small draught can cause since we’re all pretty used to the odd cold draught here and there. The reality is though, to be comfortable when we feel a cold draught, we need the room to be a few degrees warmer to counter the discomfort the draught causes. This is another example of designing or constructing a building that doesn’t perform as it should, and then consuming more energy in an attempt to remedy the situation. (Sound familiar?)

Benchmark 1: 0.6ach
The Passivhaus standard requires that a building be airtight enough to reduce air leakage to below 0.6 air changes per hour at 50 Pascals when subjected to a blower door test. While there are many technical aspects to this, in plain English it simply means that the building fabric must be draught-free. There must be no significant gaps in the walls, floor, roof and windows and doors (when closed of course!) that would cause a draught.

Benchmark 2: >17° C
The Passivhaus standard requires that windows maintain an internal surface temperature over 17° C, based on the internal air temperature of the building being 20° C. This isn’t saying that every Passivhaus building will always be 20° C inside, but rather, that the surface temperature of the windows will always be within 3° of the room temperature. This prevents convention currents forming by cold air dropping off a window that is much colder than the room. This is another source of draughts in poorly performing buildings, and the reason why (in the UK at least) buildings are often designed with radiators below windows: to counter this draughty discomfort.

Jab 2 for Comfort: No cold spots

Windows that are much colder than the room temperature are also uncomfortable because we experience them as cold spots. The glass acts like a radiator in reverse, drawing warmth away from our body. And the reverse is true in summer; the glass acts like a radiator adding unwanted heat into the room. The effect of this is a band of discomfort around the perimeter of a room where convection currents and cold spots make the space too uncomfortable to enjoy and make use of.

Jab 3 for Comfort: No overheating

Many buildings overheat due to inadequate insulation and excessive un-shaded glazing facing the summer sun. Not only is this directly uncomfortable when it gets too hot inside, it can also lead to health issues. And then to top it off, we use more energy in an attempt to remedy the discomfort. (An “Iced Tea Building”, remember?) In many climates around the world air conditioning simply shouldn’t be needed in well designed buildings, unfortunately most buildings perform poorly. This results in overheating and the need for energy guzzling, CO2 emitting air-conditioning to make them comfortable, or at least less uncomfortable.

Benchmark 3: <25° C
The Passivhaus standard requires that the indoor temperature does not exceed 25° C for more than 10% of the time it is occupied over a year. This takes into account all the internal heat sources – people, building services, cooking, computers etc. – as well as heat gained from the sun. So if a building is designed with large windows facing the sun (or with all glass facades!) then suitable external shading must be provided. Internal blinds, while being helpful to reduce glare, do not prevent overheating as the heat is already inside the building at that point.

Bonus! Jab 4 for Comfort: Fresh air

Lack of fresh air and excessive air at the wrong temperature are both very uncomfortable. We tend to think that ‘naturally ventilated’ buildings with plenty of opening windows and trickle vents should provide enough fresh air. Unfortunately this is very rarely the case (read this) as windows simply aren’t opened enough when fresh air is needed for a wide variety of reasons – for example to avoid wind, outdoor pollution, outside noises and smells etc.. We can probably all remember how stuffy our school classrooms became in winter when it was too cold to open windows to allow sufficient fresh air in.

Trickle vents are inadequate because they either aren’t maintained (except as habitats by spiders) or people keep them closed to prevent uncomfortable draughts!

And we’ve all experienced sitting under or near an air-conditioning grille blowing cool air into a room and know just how uncomfortable that can be.

Benchmark 4: 30m3/h
The Passivhaus standard requires that the ventilation system provide 30m3 of fresh air, every hour, for every person in the building. This can be provided all year round by a mechanical ventilation system with heat recovery so there are no uncomfortable cold draughts from the ventilation. Alternatively it can be provided by ’natural ventilation’ in summer and mechanical ventilation with heat recovery for the rest of the year. In either case the ventilation system needs to be designed correctly, installed correctly and commissioned correctly, all of which are important reasons for insisting on Passivhaus certification. (See my previous blog on this.)

Right Hook for Energy Efficiency

Even with all the focus on comfort, the Passivhaus standard is still undoubtably the world’s leading standard for building energy efficiency. It sets extremely ambitious yet achievable targets, provides the methodology and toolkit to accurately model predicted building performance and it has an outstanding track record of delivering. And it does this simply by design.

Benchmark 5: 15kWh/m2 Heating / Cooling
The passivhaus standard requires that the building only uses 15kWh/m2 per year for heating or cooling to maintain the building at 20° C. And yes, this does mean that if you choose keep your Passivhaus building cooler it will use even less energy! Heating and cooling makes up around 40% to 60% of energy consumption in buildings which is why the passivhaus standard singles this out specifically. And by setting an ambitious target of 15kWh/m2, which is around 10% of what typical modern buildings use, the focus is shifted beyond just selecting an efficient heating / cooling system itself and onto ensuring the building fabric performs well. It is only possible to achieve this radically low energy benchmark by designing the building to need very little heating or cooling in the first place. And of course, this ensures that comfort is kept at the forefront also.

Benchmark 6: 120kWh/m2 Primary Energy
The passivhaus standard requires that the building only uses 120kWh/m2 per year in total, this includes all uses such as heating, cooling, ventilation, hot water, laundry, cooking, electronics etc.; everything. And by having a benchmark for primary energy rather than consumed energy it ensure that there is no offsetting or energy accounting games going on. The true environmental impact of the energy consumption is accounted for and reduced. Primary energy is the measure of how much energy is needed at source to generate and deliver the energy used in the building. So on top of what we consume in the building, it includes the energy lost in the generation process, lost in any conversion processes and lost in transmission and distribution. The result is a genuine radical reduction in energy consumption.

Comfort, Comfort, Comfort, Energy Efficiency

This is how the Passivhaus standard rolls in the boxing ring; Jab Jab, Jab, for comfort, following through with an enormous Right Hook for energy efficiency. Giving, giving, giving, as Gary Vaynerchuk insists must be done, before asking. And this is what architecture in the anthropocene must provide; buildings that are comfortable and healthy and use radically less energy, one can’t be sacrificed for the other.

We need buildings that are good for people and good for the planet. Passivhaus buildings.

Feel free to thank Gary Vaynerchuk for such a powerful analogy, although I’m not sure he ever imagined it being interpreted in this context!

9 thoughts on “Passivhaus; Comfort, Comfort, Comfort, Energy Efficiency

  1. this has really given me something to think about. I have been reading up on home building and something like this would really help.

  2. Hi Elrond! Great to read about Passivhaus in plain English…I would love to read approx. costings of building to Passiv Standards at some stage!
    (recommendations of most suitable insulation etc..)

    • Dear Amanda,

      Thanks for your positive feedback, much appreciated.

      In terms of the cost of building to the Passivhaus standard, it may be a topic I come back to revisit at some stage, but costs are often so project specific that it’s very hard to make generalisations. I would suggest a few references though:
      – Cost is always a matter of priority so different projects will have different costs, and people choose to invest their budget in different aspects of a project. Some like to spend more on a kitchen, others prefer to invest in the building fabric.
      – Paul Testa Architects have generously published costings for their Passivhaus entry into the “Self build on a shoe string” competition which you can read about and download from here.
      – “The Passivhaus diaries” that Bill Butcher wrote about the Denby Dale home include cost details in this entry that you may find relevant.
      – “The Passivhaus Handbook” has a very useful section on costs. I’ll be doing a review of this book in the future, so watch out for that.

      In terms of suitable insulation, the specific details of the project need consideration. The Passivhaus Standard does not require particular materials generally, nor insulation materials specifically, the key is getting the thermal and moisture performance and details correct. Personally, I prefer natural insulation materials where possible – cellulose, wool, wood fibre, cork etc..

      Best wishes, Elrond

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