Passive Houses are energy efficient homes that are so efficient, it often it takes mentioning a few times for the reality of this statement to sink in: “Passive Houses are built without central heating systems“. It’s so curious and novel and almost unbelievable, in this day and age where the greatest part of our monthly utility bill goes toward space conditioning.
How this actually works is quite simple when compared to a thermos bottle, since a thermos is so well insulated the contents retain most of its heat, sidestepping the need to constantly produce new heat to keep the contents warm. Same as a Passive House.
Given the high insulation levels and air-tightness of a Passive House, it requires almost no active energy to create indoor heat, it is most often sufficient enough for the ‘contents’ (occupants, light bulbs, and appliances) to generate enough heat for the home to remain perfectly comfortable.
Also, without an expensive or complicated central heating system, this cost savings offsets the cost of construction, making a Passive House the most economical choice of all the green building methods out there today.
To illustrate the point about heating, the first image below is a thermal image of a coffee maker, representing any home with an “active” central heating system required to keep it warm and comfortable. The red, yellow and green indicate varying degrees of heat loss from the container. The second thermal image is of a thermos, where through “passive” insulation and airtightness the contents can easily retain the heat, you’ll notice no color other than blue, which represents coolness (ie no heat loss).
Building a house with no central heating system can sound risky, but you can see how simply elegant and intelligent it is once you imagine putting your resources into the passive components such as the insulation, air sealing, super efficient windows and a small air handling system for fresh air.
It’s hard to resist the lure of energy independence and a Passive House puts a person well on their way!
Posted on July 06, 2010