Controlling heat loss

I am always impressed with the winter survival strategies of animals: bears that metabolize their fat, inactive frogs that nearly freeze and active birds that drop their body temperatures.  This last thermoregulation strategy – reducing body heat to minimize heat loss – is one that has direct human applications.

Ducks in an icy lake

 
In the winter, ducks swim in very cold water and stand around on ice.  Why don't their feet freeze?  Why doesn't their body heat quickly drain through their feet, slowly cooling them?  How do duck feet work with the rest of the duck body to keep it alive in the cold?

The winter physiology of ducks is a marvel of biological engineering, where many sophisticated systems come together to sustain a warm-blooded animal in a very cold environment.  For the purposes of this blog post I will highlight only one aspect of duck physiology – reduced foot temperature – which is beautiful in its simplicity.  First, a question:

On a winter morning, which will lose heat faster.
A) A hot cup of coffee
B) A can of cold soda

Answer: A, a hot cup of coffee will lose its heat faster than a cold can of soda. *if your dying to know why, click here.  It makes sense, then, from an energy conservation perspective for a duck to maintain a lower body temperature in winter.  The obvious hiccup with temperature reduction is that bodies need to stay warm enough to carry out their biological processes (which are temperature dependent); simply reducing body temperature could result in a loss of the body's function.  The duck does a wonderful job of keeping its body functioning while reducing its temperature.  It does this by breaking its body into different heating zones. 


A temperature diagram of a common gull.  Like the mallard duck, this gull sustains a high temperature in its core, but – to conserve energy – allows its legs and feet to cool dramatically.   

So what does cold bird feet have to do with Living Lighter on the Land?  The Armstrong House is actually a lot like the duck – they are both broken up into different 'zones' and which are heated differentially.  Once the Armstrong House's heating system is completely finished it will be broken up into different heating zones (which roughly correlate with the different rooms), where some rooms will be kept at lower temperatures to reduce heat loss.  By slightly reducing the temperature in less-used rooms or rooms that don't require much heat, the Armstrong House's overall energy consumption is reduced.  Also, the different zones can be managed to have their temperature's fluctuate over time.  For example, the whole house temperature can be reduced at night and specific zones can be heated in the morning in the order in which they are used.  For instance, the bathroom can be heated first, then the kitchen, then the office.  In fact, the zones can be managed to reflect the occupant's schedule.  Zones that are unused during the day (bedrooms and master bathroom) can be lowered until 4:00 pm – just in time to be warm for the occupant returning from work.  Likewise, primary rooms where the most time is spent (like the kitchen and living room) can be grouped as a zone that stays warmest.  The mud room, sun room and work room can be zoned together and kept cooler. 

In surfing the web I found a neat house in Vermont that is similiar to the Armstrong House.  They too understand the benefit of zoning their house and heating based on use (see below). 

The three heating zones of 'Perfect House', an energy effecient house in Vermont. 

   
I love my warm and cozy house, so I am certainly not advocating for living in an icebox.  I am convinced that a comfortable environment can be kept inside the home and energy can be conserved by strategically managing the temperature of various zones.  If the mallard duck can stay active in a half frozen pond, we can surely figure out better ways to thermoregulate our houses to conserve energy.