Frequently Asked
Questions
Common Misunderstandings about Passive House
Some people in the architecture and Housing industries who feel threatened or confused by the potential of the Passive House concept attempt to dissuade people from using the system by spreading rumours and giving out false information about Passive Houses. This has lead to a number of misunderstandings concerning the construction, use and comfort levels achievable with the Passive House system.
The following information is a collection of the most common misunderstandings surrounding the Passive House concept. This information is aimed at clearing up these misunderstandings and reassuring people who are interested in building with the Passive House concept that the system is not only secure, but that Passive House is indeed the building method of the future!
Questions:
- 1. In a Passive House you cannot open the windows?
- 2. Because of the Mechanical ventilation system, there is always a draft?
- 3. A Passive House has no heating?
- 4. A Passive House has to always be a "box shape"?
- 5. Passive House technology is not very well developed yet?
- 6. A passive house can only be built on sunny ground?
- 7. A Passive House is much more expensive than a conventional house?
- 8. A Passive House is always cold?
- 9. The individual rooms in a Passive House can not have different temperatures?
- 10. An old house can not be restored into a Passive House?
1. In a Passive House you cannot open the windows?
Following recommendation from the PHI, It is possible in every Passive House to open the windows. The House/ apartment’s technical ventilation system ensures that there is never bad air inside the building. This is true even if the buildings windows remain closed indefinitely.
2. Because of the Mechanical ventilation system, there is always a draft?
Quite the contrary, with Passive House there are never drafts because the building is detailed in such a way as to achieve superior air tightness. The fresh air flowing in to each room via the ventilation outlet on the ceiling is no longer noticeable passed a distance of 30cm.
3. A Passive House has no heating?
In general, a Passive house needs a "small" heater, because it is not a zero energy house. The other methods for heating the building come from passive sources such as the sun, appliances and inhabitants body temperature, so yes it does have heating - passive heating!
4. A Passive House has to always be a "box shape"?
Where does such a statement come from? There are thousands of passive houses with a variety of forms and shapes. These include: pitched roofs of all angles, hip roofs, circles, cylinders and cone shapes. There are no restrictions with the buildings form and therefore no lack of diversity.
5. Passive House technology is not very well developed yet?
The passive house concept does not rely on a large degree of technology in order to operate. Mechanical ventilation with heat recovery is the only specific Passive House requirement and this technology has been used successfully in Canada and Scandinavia for more than 50 years.
6. A passive house can only be built on sunny ground?
Well, this misunderstanding is probably the resulted of confusion with the "passive solar" approach. Passive houses are possible even on urban land, where the main facade points north. Therefore there is no excuse for not building a Passive House.
7. A Passive House is much more expensive than a conventional house?
The last survey showed a four - eight Percent additional investment (It may be possible to acquire grants to offset these additional costs). Later, however, you will get this money back due to the buildings reduced energy costs: Per year the inhabitants save between €800(£746) – €1500(£1399) in operating costs. Anyone who realistically thinks about the future will recognise that they may soon not be able to afford a less efficient house due to the reduced availability of commonly used energy sources and their ever increasing prices.
8. A Passive House is always cold?
This is not true. Passive Houses are designed to maintain a constant indoor air temperature between 22 - 24˚c in both summer and winter (without additional costs for heating in winter). However it is also possible to have the house warmer or cooler based on the inhabitants personal preference.
9. The individual rooms in a Passive House can not have different temperatures?
The building temperature depends on the preference of the occupant. There will be varying temperatures between rooms on the North and South sides of the building. It is also possible to design in cool cellar rooms (or unheated areas) without compromising the temperature of the buildings heated areas.
10. An old house can not be restored into a Passive House?
That is true in general. But that is only a half truth: you can fit Passive house technology in to old buildings such as: good external insulation, triple glazed windows, and ventilation with heat recovery. The problem is that in many cases it will be very difficult to reach the strict passive house standards (of 15 kWh / (m²a)) without completely renovating the building inside and out. This approach would result in spending more money than is required in the long run. Of course, the renovation of an old building to Passive House standards is not impossible and there are examples of successful renovation projects across Europe.
This information was taken from an interview with Dr Wolfgang Feist for the Magazine of IG Passivhaus Tirol. Copyright of Dr Wolfgang Feist.