Environmental Stewardship Commission (MEESC)

From "A Resolution on Church Buildings and Grounds, and Church-Related Activities"
passed at the 143rd Annual Convention (October 27-29, 2000)

"THEREFORE BE IT RESOLVED that the staff and membership of the Episcopal Diocese of Minnesota engage in building actions and cultural activities with prayerful considerations about the impact these actions will have on our Earth home.  Ways we will live into this approach are concentration on reduction of energy and resource usage through retrofitting and/or replacement of inefficient heating/cooling, plumbing and ventilation systems."

Thoughts on how to implement this concept
by Bert Whitcombe

A basic, common understanding of thermodynamics is essential to environmental stewardship in these times.  No math, no complex physics, just what’s happening in the world (the universe) of heat and cold and how it affects our church community, the earth and ourselves.  The most direct savings are monetary; they also include resource conservation and global warming reduction.

As far as how the hot and cold thing works, first and foremost heat moves to cold. So when we say that the cold is leaking in, we feel a cold draft, actually the heat is leaving, it’s doing the moving.  This has caused some to speculate that the universe is destined to seek stasis, a steady state, achieving a universal temperature, which has lead others to speculate on physical and Meta-physical stuff, but that’s another matter.

Another important principle is that the desire of heat to move to a cold place is not constant.  The greater the difference between the hot and cold places, the stronger the heat’s desire is to leave.

For instance, in Minnesota, when its –10º F outside and 70º F inside the heat is very anxious to be going out into the cold, which makes its desire to go out much greater than that of most Minnesotans.

When it comes to those warm houses and churches there are two ways for the heat to leave, warm air leaving and radiation loss.

Taking up  ‘air infiltration’, being the term used in the trade, odd seeing as it’s actually the heat leaving, not the cold coming in.  Ok, ok, you can actually feel cold air coming into a room when the outside door is open, but it is coming in (positive air flow) because warm air (negative air flow) has left.

Time for another part of the thermal saga, warm air is lighter than cold air, which is soon to become important information.

Ok, warmth wants to leave, how do we stop it?

1. Make sure that there are no air leaks, especially in the upper parts of the building, remembering that the greater the difference between in and out, and that the hot air is going up, there is a great urge, on the part of the heat to go out holes that are on the upper reaches of the building, which creates a vacuum, or great desire to suck cold air in from the bottom.
2. Regulate how easy it is for the cold to get in.  Storm doors and windows and double entry doors are inventions to accomplish this.  It works sort of like entering a city speed limit and first the speed drops from 55 to 40 and then to 30.

And onto the radiation issue.  By preventing the air from leaving as per above we have taken the first step – but heat has a very great desire to leave so we need to create an additional obstacle, we need to thicken the envelope with thermal resistance, insulation.

This resistance issue also is not constant.   There are two factors:

1. As I mentioned before, if there is a greater difference between in and out, there will need to be more thermal resistance to keep the heat in.
2. The thermal resistance is measures in R units, R1 resists 50% of the thermal heat loss, R2 resists 75% of the loss, R4 87.5% and so on.  The way it works is this, doubling the resistance (insulation) stops ½ of the remaining heat loss.

Addressing thermal loss:

1. Windows are prime air infiltration sites and very low in thermal resistance, R2 maybe.  Curtains of all kinds help, the tighter (close the top of the curtain envelope) and the thicker (more thermal resistance) the better.
2. Increasing the R-value will always pay off in the long run, but these pay backs take much longer, addressing air infiltration losses first is the usually the best plan.
3. A somewhat separate thermal loss issue that can result in huge savings is higher efficient heating plants.  Older units can be operating at as little as 40% efficiency while modern appliances often are 95% efficient.

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