You can apply any of the seven Passive House principles to improve your home’s performance without going all the way; just make sure to ventilate.
1. Superinsulate. Depending on the climate, Passive Houses might have a foot or two of insulation in the roof, walls and floor (homes often have just a few inches of insulation in these areas).
2. Eliminate thermal bridges. Careful detailing prevents heat from moving through edges, corners, connections and penetrations in the envelope.
3. Make it airtight. The entire building envelope must be airtight to avoid heat transfer and minimize drafts.
4. Use energy- or heat-recovery ventilation. Ventilation equipment provides fresh air and circulation with minimal energy waste.
5. Use high-performance windows and doors. Windows and doors that greatly reduce heat flow virtually eliminate cold winter drafts and cut way back on summer heat gain.
6. Optimize heat gains. A Passive House consultant can predict and balance heat from the sun and internal sources (cooking, lighting, etc.) and prescribe appropriate orientation and window placement for maximum comfort with minimal energy use.
7. Model energy gains and losses. The Passive House Planning Package (PHPP) is a complex energy-modeling tool trained consultants use to assess various combinations of insulation, windows, wall types, airtightness, ventilation systems and other components to create an optimal system for a given climate and budget.