How do we get a better 'Passive House Mindset'?

High energy prices seem to be here for a long time to come (perhaps permanently), and it now seems more likely than not that we’ll break through the 1.5°C Paris Agreement global heating limit. And with buildings and construction accounting for about one third of energy demand in 2021, how can we encourage people to think about ways of reducing the need for energy - principally for heating and cooling - in our homes?

Ultimately, we’ll only significantly improve the energy efficiency of the UK’s housing stock with adequate government support to incentivise the building industry and the suppliers of building materials, as well as local planning authorities and the individuals who own these buildings, to do so. Meanwhile, we need to encourage more and more people to think about how improving the energy efficiency of a majority of our new and existing homes is not just a possibility but an urgent necessity.

Improving energy efficiency in a home

There are some important principles we can take from the Passivhaus standard (pictured, right) to improve the energy efficiency of many existing properties, including:

• better insulation;

• avoiding bridging of, and gaps in, the insulation layer;

• rigorous draught-proofing;

• high quality windows, properly installed; and

• adequate ventilation (preferably with heat recovery).

The principles of a Passivhaus building. See: The Passivhaus Institute - Passivhaus requirements

Substantially improving comfort in a home

It’s also important to consider other benefits from this approach - it’s not just about keeping warm in winter:

• the five Passivhaus features in the diagram above can also contribute to keeping homes cooler in summer (with some additional things like adequate shading); and

• they substantially improve indoor thermal comfort and air quality, with the elimination of draughts and condensation.

Put simply, more energy efficient homes are much nicer to live in!

The benefits of living in a Passivhaus

A striking feature of a Passivhaus is the evenness of the indoor temperature, as shown in the chart at the top of this post. This shows the indoor and outdoor temperatures at Woodlands B&B in Malvern throughout 2022 measured by data loggers at 30-minute intervals. Even in the July heatwave, the indoor temperature only exceeded 25°C for 60 minutes, and when it was -9.77°C outside in the December cold snap the indoor temperature only dropped to 19°C (requiring only a slight boost from the underfloor heating pipes covering just 25% of the total floor area).

There is also little temperature variation between rooms (perhaps 1-2°C), and you can use the floor space right up to the windows: when it’s very cold outside the inside pane of the triple glazing is roughly the same temperature as the room so there is no ‘cold radiant’ from the window and there are no convection currents creating cooler areas near the floor and hotter ones near the ceiling.

Thinking more about passive house principles for existing homes

There are some 25 million dwellings in the UK, and at current new-home building rates of some 200,000 each year there will only be an extra 5-6 million new homes by 2050. For individual self-builders, a high energy performance home is a possibility, but for the UK as a whole, we can’t solve the energy and global heating crises we face just by building new high energy efficiency buildings.

Rather, we need a multi-faceted approach. One aspect is to convert suitable current properties to the EnerPHit standard, which is very close to the new-build Passivhaus standard and accounts for the fact that not all aspects of this can be achieved in existing buildings. Another, where achieving EnerPHit isn’t feasible, is improving what is possible in terms of insulation and draught-proofing - noting that this will also require a systematic, properly designed ventilation strategy if condensation and damp is to be avoided. Because we all breathe and sweat (losing 200-1500ml and 0.5-10L, respectively, each day depending on levels of activity), and we shower and bathe, and cook and wash clothes, there’s a lot of water vapour generated inside our homes. Draught-proofing reduces heat loss and increases comfort but needs to be balanced with, preferably, a heat-recovery ventilation system to avoid mould and damp from all this indoor water vapour generation causing damage to the fabric of buildings and making indoor environments unhealthy.

In addition, there is also a need to help people convert to using more efficient heating systems; as well as helping to train designers and builders to undertake their work in slightly different ways.

A brief guide to retrofitting for energy efficiency

A more detailed guide to deep retrofit and why to do it

Is it worth it?

Building new to the Passivhaus standard is a bit more expensive than doing so to current building regulation standards (see Is the additional cost of building a Passivhaus worth it? towards the end of another post), and undertaking a deep retrofit project (whether to EnerPHit standard or otherwise) is a significant undertaking.

But, based on our experience of living in a certified Passivhaus for four years, we’d say that it’s not just the very substantial reduction in heating bills to consider. Most important - for us - is the improved living environment: a bright airy living space, without draughts and with a near-constant temperature throughout regardless of the weather provides a peaceful and, almost paradoxically, cozy environment that is simply wonderful to live in.

All current homes, and the people living in them, are different, so you will need to consider what are your values and priorities as well as how long you expect to live there if you’re thinking of making your home more energy efficient.

You can experience the Passivhaus difference yourselves at Woodlands B&B and we’ll be pleased to share our experiences of self-building and living in a Passivhaus with you.