There are so many questions that go around when you're talking about construction, let alone when talking about the relatively new concept of passive house. There is a mountain of knowledge out there but you need to be able to whittle it down and find the right sources, the right information and the right concepts for you.
House building has various different elements; structure, water and drainage system, roof construction and heating system, just to name a few. If you've been in this business for a while then the standard practices are likely second nature but, what about when you're talking about a passive house?
Firstly, how do you heat a passive house without all of the basic elements that we are used to? Passive houses are designed to be energy efficient. By making sure that the build is airtight for example, ensures that other systems, such as heating , can work at full capacity. The heating demand in a passive house is only around 10% that of the energy used in a conventional build.
In a Passive House the heat can be distributed relatively easily without too much effort from the supply of air coming from the building's ventilation system. The ventilation system actually serves as dual purpose; fresh air and heating. "A passive house has a space heating energy demand of <15k Wh per square metre of living space per year. Compared to the UK new-build common practice figure of 55kWh/m2/yr" - https://www.buildingtalk.com/eight-ways-to-heat-a-passive-house-this-winter/
Some passive houses benefit from the use of electric post-heater. This can be used alongside a heat recovery ventilation system (MVHR)
Solar heating is another option. Panels are fitted to the house either on the side or the roof or even placed on the ground. Again this can be linked with the MVHR system.
Ground Source heat pump is a heating and cooling system and has a low running cost and high performance. The system uses the temperature of the ground as a heat source in the winter and a heat sink in the summer.
An air source heat pump has many of the same benefits as the above. Essentially it absorbs the heat from the outside air and releases it into your home.
As I have mentioned above the MVHR (Mechanical Ventilation with Heat Recovery) is the system that will provide fresh filtered air into your home while retaining most of the energy that has been used to heat the building.
There really are many more systems for you to think about and I could go into far greater detail with the ones that I have listed. The above is a basic outline of some of the different systems that can be used to heat your passive house. You need to work out what is going to be best for your build and remember that building a passive house requires each system and the structure to work in harmony together.
The key to building passive is in the design and the intricate details. The fabric of the house will provide you with the base that you need.
Build better, build stronger and build passive!