I'm glad this whole subject was brought up because it is really appropriate to my philosophy of using active solar heating and cooling in minimalistic ways. It sounds like a contradiction but I don't think it has to be. I'm really not sold on the passive house approach of forbidding ACTIVE controls for natural heating or cooling or, for that matter, eschewing installation of photovoltaic panels. I think their approach is too restrictive and makes it almost impossible to maintain a constant temperature range within 3 degrees F, plus or minus, of the desired temperature.

For instance, if you design a system for gaining window radiation shining on a dark colored slab it only works well for "average" days for your climate. It is likely to be too hot sometimes and too cold others. Their idea of insulating to maintain temperature is great but it only goes so far.

So I decided to go ahead with plans to install an automatic whole house fan in my house. It will complement the system I'm already installing that uses a radiant barrier in combination with two automated dampers to retain heat from the attic and bring it down into the house in winter. I'm insulating the house really well, not quite to passive house standards but pretty good, so I won't be putting a huge strain on my goal of keeping the house within +/- 3 degrees F of the desired temperature during the day. Who knows if I'll be successful but god is it fun trying:p

I'll post a new thread and put a link here when I've gotten a bit more organized. It will definitely involve Arduinos and a bunch of backdraft dampers.

I'll just make one more (off topic) remark about why I think Passivhaus is misguided in many of their restrictions. I'm not talking about their emphasis on insulation. They are always talking about using passive solar heat from solar heat through windows. That's all well and good if it never gets too hot but that's almost impossible. Rather than use windows that you really can't control much wouldn't it be better to use something else that absorbs solar radiation and then choose to admit or not admit it through automation.

It's not at all a matter of Passivhaus being purist. After all, what is a heat pump that heats or cools? It's an automated control system. Really, all Passivhaus is doing in their quest for purism is saying "you can use active systems for non-renewable energy sources but you may not use active systems under any circumstances for renewable energy sources."

That's just dumb. End of rant.