I've often come across customers building a "low energy" or "near passive" house.  The thing is, in all these descriptions of what they would ideally like - no or a very low heating bill, the most important item missed in achieving their goal is air tightness.

Far too often, insulation companies push the merits of insulation, our building regulations push U values.  Both are meaningless without air tightness.

The passive house "experts" (long hair and a foreign accent help!) insist on large windows facing south and very small ones facing north.  Triple glazed, super sealed and as few opening as possible.  All very well at retaining heat, throw in good air tightness and heat recovery and there you have a passive house?   Wrong!!

Thats not the way it works.  We sell comfort, not just  heat recovery, heating and air conditioning.  You can go to your local electrical outlet and buy some electric heaters and now you have heat.  Great.  Do you have comfort?

You can build your "passive house", have near zero heating bills, but will you have comfort if the sun beats in the large south facing windows and it is 25C outside?  You will not.  

Can you use a standard heat recovery unit to ventilate your home during hot weather and cool you home by introducing only fresh air?  No you can't

My point is that when considering a "passive house" consider comfort.  If you are happy with 18C indoor temperature in the depth of winter or 25C or warmer in the height of summer, then a true passive house might be the way to go.

However, if you value comfort then no matter what type of home you build, comfort along with energy efficiency should be foremost in your design.

Eamon