Results

O. K., how did all this work?  This is entered as a journal, newest entry first, because work is continuing. 

August 11, 2009:

Here's the latest results, for the year ending with the June 2009 bill.  

It looks like our efficiency measures and sealing cracks is paying off.  As you can see, space heating (227 therms) was about 44% of the average of the three "uninsulated" years ending June 2007 (516.67 therms).  Woo hoo!  Also, total therms of 275 was just 43% of the previous "uninsulated" average of 647.33. 

It was probably a bit better than it should have been.  Point number one, we spent almost two months without hot water last summer after our old water heater failed.  Back-of-the-envelope, I figure that in the normal scheme of things, we'd have 8 additional therms.  Point number two, this January was one of the mildest Januaries we've seen in a long time -- average temp was 39 F instead of 28 F for last year.  We clocked 48 therms used, but it would have probably been more like 54 therms (another back-of-the-envelope estimate) in a normal January.  

Feb. 2, 2009:

I had two further thoughts about ways to improve the insulation, which I have now added to the "further work" section.  One is that the air exchanger may be oversized.  The second is that there may be thermal bridging, big-time, through the door steps, and the front and back porches.  There is nothing but concrete (with a very low R-value) between the concrete block / brick thermal mass on the inside and the outside air, where the back porch, front porch, and doorsteps connect to the house.  While the total area is small, this may be significant because concrete conducts heat so well.  

Also, I have found some sources of information which may be interesting:

The Thousand Home Challenge (PDF) 
This is coming soon to North America -- I think they will start the challenge in the spring or summer of 2009

Passive House Institute (USA) 
This seems to be oriented towards new construction.  They offer a design package for $200.  I'm not sure about whether their consulting services are available in Colorado, though I doubt it.   

You can also download the RETScreen Clean Energy Project Analysis Software for free from Natural Resources Canada.  

Oct. 27, 2008:

Here are the results during the from the first year's work (July 2007 - June 2008).  The insulation was not actually installed until about October of 2007, but of course the insulation didn't matter for the summer months. 

Bottom line, the therms required for space heating was about 54% of the average space heating in the three previous years.  Not bad, although we were hoping to get an even lower percentage than that.  During this entire time, both before and after installing the insulation, we kept our thermostat set at 68 degrees F. during the day, and 62 degrees F. during the night.

In case you're wondering, I got the total therms from my utility bill.  I then calculated the water heating for the year based on the average monthly therms during the summer months (June, July, August) when there was no space heating requirement, and then multiplied this monthly average by 14 (figuring that the water is colder in the winter months and thus requires more heat).  The space heating requirement is the difference between these two figures. 

Because we wanted to do better than 54%, I did an infrared test on the house last March 2008 and found that, indeed, there were numerous cold spots around the house, especially around the edges of the ceiling of the house.  The windows seemed to be pretty tight, though.  So we spent another $2000 and got all the various leaks plugged up.  We'll see how it goes this winter. 

Woo-hoo!  Our new tankless hot water heater.

Also, this summer our water heater gave out and we've gotten a "tankless" gas hot water heater, so we'll have to recalculate the portion of the bill that goes for water heating, as we anticipate this portion of our bill will be further reduced.  The "tankless" gas hot water heater has nothing to do with insulation, but it will reduce our total natural gas requirements.

Also, speaking of the summer, you may be wondering how this works in the summer.  It did not seem to make that much difference but did keep the house a bit cooler in the summer.  We found that on the very hottest days of summer, when the temperature outside got up to over 100 degrees (as it did last summer on a few days), that the temperature inside got up to 82 degrees.  In the basement it never got above 75 degrees or so the entire summer, so it was quite tolerable in our 2/3 finished basement.  One summer evening we had a meeting at our house and met in the basement -- quite agreeable.  We have no swamp cooler, air conditioner, or whole-house fan or anything like that.  We cooled the house off during the evening by opening the windows and turning on fans around the house.  

Stay tuned for further results.