Passive Solar and Passive House – why you should consider the shift.
I am not saying that passive solar/solar passive is terrible. I’m saying it is outdated.
We saw the same in the printing industry, the phone industry, and now the building industry.
I am not saying that passive solar designers are bad either.
Both passive solar designers and Passive House designers want the same thing: healthy and sustainable homes. Am I not right?
We want the same outcome. At this point, I want to say thank you to all the passive solar designers who have been working hard over the last 50 years. Passive House is strongly based on your work.
Passive solar designers have a massive advantage over other designers because they are used to thinking about the performance of the building. Passive solar designers are used to working with the sun, the environment, and materials to make a house perform at its best.
They develop a sense of whether a home is functioning or not. A passive solar designer will be an excellent Passive House designer.
At this point, I would like to say that Passive House is not a religion – it’s a standard and a concept. The Passive House standard is not always the perfect solution, but the Passive House concept/approach is the best we have until we find something better.
Reduce the energy consumption, check if it is economical, and reduce again until you come to the point it is not economical. Now you know where to go.
To the topic of ventilation
For some time now, I always travel with an air quality sensor in my suitcase.
I have not stayed in one building where the air quality was good without active ventilation like mechanical ventilation or keeping the windows open.
If I close the windows, in a couple of hours, the CO2 level is above the maximum requirement for health of 1000 ppm. It’s also worth noting that the air quality is only healthy in the rooms that have the windows open; in the other rooms where the windows are closed, the air can still be bad.
I came to the sad conclusion that all buildings need active ventilation if we want to guarantee a healthy environment. The only way of avoiding active ventilation is by keeping the windows open 24/7 on 365 days of the year.
Window ventilation only works in a really mild climate with a temperature span of about 17–27 degrees.
Ventilation is a health requirement in any building, and it is not unique to Passive House. The only difference is that Passive House is making this health requirement a must to fulfil the standard.
This means passive solar needs active/mechanical ventilation, too, if they want to ensure the air quality is healthy.
Now, to economics
If a passive solar house was to keep the temperature constant in the comfortable zone of 20–25 degrees Celsius, it would cost more to run and build compared to an equivalent Passive House.
Moreover, it would need to be calculated as it is with Passive House to make sure what is built achieves this performance.
- Lower temperatures will cause too high a mould risk.
- Higher temperatures are not comfortable without running an active fan, which could be acceptable to about 27 degrees Celsius.
20–25 degrees Celsius is comfortable, healthy and safe.
Passive House has no guesswork when it comes to economics.
Passive House allows for some heating and cooling because zero energy is not economical.
Every decision can be made upfront keeping the economics in check.
Now to the question: “How much more does a Passive House cost?”
From 10% less to about 20% more.
Yes, it could even be cheaper to build than traditional construction.
Generally, it costs more to build, but over the lifetime of the building, it will be economical, and energy-price fluctuations have nearly no impact on a Passive House.
The break-even point is usually reached before the end of the loan repayment.
I hope this explains why the Passive House approach is the way to go, and I recommend every passive-solar designer to undertake the Certified Passive House Course.
If you are in or want to come to Australia, you can do the course with me. However, the course is offered worldwide, and I am sure there is a provider close to you.
Passive-solar designers, you can be the elite of Passive House designers and help less-experienced designers to improve their skills.
We are all in the same boat and have equal responsibility for the health of our clients and to reduce the 39% of the world’s CO2 emissions caused by construction and the use of buildings.
This is your opportunity to become Passive House certified. Visit our website here for more information.