In cold climates or areas with high air pollution, this system makes sense and we use it. We don’t generally recommend it, however, in West Coast beach communities.
The Passive System
The passive system uses an extremely tight building envelope that is highly insulated. We used to call this the “thermos bottle” concept. Mechanical equipment then lead generation controls air coming into the building, heating, cooling, or cleaning it. Heat from air leaving the building is captured by equipment and reused.
Passive houses tend to be a lot more expensive than the type we design for the California coast. First of all, the windows required in passive houses need to be especially tight, of a type not general available in America. The special equipment to condition the air and capture waste
heat is also quite expensive. Moisture created inside the house, from cooking, showers, laundry, and just by people breathing can build up and cause mold if not very carefully controlled.
When Not to Use It
In moderate climates with clean air, like beach towns, we like building envelopes that are NOT tight. We like lots of open windows for airflow. We don’t rely on heating the air to make people comfortable – we use radiant heating instead.
Next to the Pacific Ocean, the air is extremely clean. After all, it has passed all the way from Hawaii over the water and lost most of any pollution it once had. Ventilation in our buildings clears any “off-gassing” from building materials, cooking odors, excessive moisture, etc. We heat our floors to a temperature of about 80 degrees so no matter what the temperature of the outside ventilation air is, the occupants feel toasty. The radiant floors heat the solid objects in the room (like people) rather than the air. The equipment to make all this work is simple, time-proven, and long lived.
