1. What would be the difference between Passive House and Green Zero Carbon houses?
A: PassivHaus focuses on passive solar gain as a big part of its energy saving. I do not. Passive solar gain from big south-facing windows leads to massive overheating on sunny days in winter, which is very bad for energy efficiency. Windows (good ones are R4-5) are less insulating than a wall (a bad one is R12) so any time you have a window rather than a wall, you have heat leaking out in winter and heat leaking in in summer. If you have big windows you have big holes in your thermal envelope. PH also is a philosophy of perfectionism. I am totally pragmatic and have no ideology. I look FIRST at what saves money and makes a good return on investment. PH does not look at cost effectiveness at all. In my opinion, this is why the PH movement has really struggled to become established in over 30 years of trying. At the end of the day PH is expensive to implement and very time consuming because of their detailed audit requirements. Frankly, it is also a lot of hassle to do everything to the Germanic standards of perfection and record everything in their software package (the PassivHaus Planning Package), which is so complicated it takes days of training to get certified to use it. Also, PH makes no accounting for where the house is located (you may have noticed that Canada has colder winters than Florida but the PH standard is the same in all locations) or how big the house is. Both location and size are key drivers of energy use and energy efficiency. PH has no standard for a renovation, it only applies to new construction, which means it is irrelevant to the 99% of all houses that are already built each year. Finally, the PH emphasis on air-tight construction has led to excess condensation and mold in PH construction. My fab four recipe was developed for retrofits, but when applied to new construction it is cheaper and easier to implement than on a renovation. See my post here: https://greenzerocarbonhome.com/2020/06/can-you-use-hits-to-build-a-new-house-with-a-zero-carbon-footprint/
Also see this article on better ways to measure energy efficiency:https://greenzerocarbonhome.com/energy-and-finance-terms-explained/net-zero-passivhaus-leed-certification-zerh-and-hers/
2 Replies to “Q: What would be the difference between Passive House and Green Zero Carbon houses?”
Hm, Passive House focuses on super airtightness, super insulation without thermal bridges to avoid adding extra heating and cooling. Mold was a problem of the 70s when the air exchange was not installed. They are build so that they profit from solar heat gain in the winter, and, with the help e.g. of overhangs, avoid it in the summer: https://www.phius.org/what-is-passive-building/passive-house-principles
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