Heating it up!

I got back to the van tonight after a technical user group meeting.  It is for a computer language I am trying to learn well enough to get by in my current gig.  An ice storm is just beginning.  Ah the joy of the frozen north.  Snow is predicted for later tonight and into tomorrow.  Just walking across the parking lot was a slippery adventure tonight.  It was not lost on me The Wife is still recovering from a fall.  By tomorrow sometime we are supposed to have five fresh inches on the ground.  Everyone’s morning commute is going to be a drag.  Even mine.

Sitting around inside I turned the furnace up.  It has been warm this week so I figure I have the propane to spare.  I hefted the tank on Monday night and determined switch-over must have taken place that day.  I think I had been running on the prior tank since Thursday but there were two very cold days in there followed by some not bad.

Sitting here tonight it occurred to me I should test my CO2 detector just to make sure the freezing temperatures in here hadn’t killed its battery.  I couldn’t find it anywhere.  I have done some level one digging around so far tonight.   I will think about it tomorrow and check in my cubical.  I know I have a couple of boxes of van parts in there.  There might be a couple more unlikely spots I can check in the van, but if that doesn’t turn it up I am going to have to buy a new one.   Just because I don’t see it anywhere doesn’t mean it wouldn’t turn up first thing in a forensics investigation.  I could just read the headlines, “Man found dead of carbon monoxide poisoning in van, CO2 detector found in cardboard box under the front seat.  Always thought to be a slow learner.”

The topic for the week seems to have been related to keeping warm.  I realized in that I haven’t mentioned the heat source much.  I have a Suburban RV furnace installed.  It is a 16,000 BTU unit hooked up to a wall mount thermostat.   The furnace runs on propane.  My fuel source is exchangeable twenty pound propane cylinders just like you use in your gas grill.  I can exchange them at most every gas station and many big box stores.

On the outside these propane tanks are all created equal.  But, what’s inside or I should say specifically how much propane is inside is another story.  You see all propane cylinders are not filled with the same amount of gas.  They are a twenty pound cylinder, meaning they *can be* filled with twenty pounds or about 4.7 gallons of LP gas.

I am a data collecting geek though.  What that means is after a few tanks I started questioning them weighing differently.  I bought a digital bathroom scale.  Nice one.  Cost me less than ten bucks at Target.  I weigh the tank when I buy it and record it’s weight in a spreadsheet.  Before I exchange it I weight it again.  The most gas I have ever gotten was eighteen pounds.  Typically it is more like mid-fifteens, one time only 14.4.  The lightest ones are not surprisingly from the gas stations.  Usually the brand on them for this area is Blue Rhino.

An empty tank runs about seventeen pounds so this one
is pretty good.  Almost nineteen pounds of propane in there.

Where the math starts to get interesting is when you start looking at the price per pound.   I park close by to a couple of Holiday stations where I can do propane exchanges.  But those tanks will be lite so I go through them quicker, and more expensive per pound as well.  At those places I am paying $1.20 to $1.54 per pound.  But, if I drive a few miles to a southern suburb I can get the eighteen pound fills for $ .96.  Quite a price difference.  But, is it worth the drive?

I am going to need another month's worth of data to really give you a good report on propane usage.  I feel like I am buying a propane tank typically every six or seven days.  Those really cold days it is more like four.  I hope to make a few changes in the next two weeks to improve that.  The complication is it will be tough to directly tie my usage to my purchases.  You see I have two tanks with a switchover valve between them.  When I finish one tank, it switches over to the other one.  But me, I am a procrastinator.  I only have to buy propane before the other tank runs out.  Just like I said earlier, I think one of my tanks went dry on Monday, here it is Wednesday.  I might not exchange it until Friday before I head home, but I can’t say that tank lasted me eight days.  It didn’t.  With enough data, I can level that all out with some averages.

This one, not so good.  Just over fifteen pounds.

The furnace also needs electricity from my batteries to run the blower fan.  I have been a little surprised how much the furnace draws.  It is enough I have been minimizing my other electrical usage, particularly during long multi-day grey spells where I am picking up very little solar.  Those days I watch my battery level indicator pretty close.   Now one thing that is on the upside.  Those really bitter cold days, where the furnace is running a ton, tend to be clear sky days.  Pretty good solar.

4.23 lbs per gallon a full tank should have 4.7 gallons in it.  So a full tank of propane should contain 420,000 btus in it.  My furnace being a 16,000 BTU unit should run 5.7 hours on one gallon of propane if it runs 100% of the time.  I have the capability, just not sufficient electricity to monitor and log my furnace run time.  Some day it will be interesting to correlate all this data.