From: amdx@knologynotthis.net   
      
   On 12/9/2012 8:10 AM, Ron Rosenfeld wrote:   
   > On Sat, 08 Dec 2012 20:01:14 -0600, Jim  wrote:   
   >   
   >> My daughter moved to Alaska a few years ago, and they recently   
   >> moved into a small house belonging to a friend who is now   
   >> living in Hawaii.  The house had been vacant for some time,   
   >> and they worked a deal with the owner (a good friend) to keep   
   >> the place up and do repairs, etc.  They got the oil furnace   
   >> working, but since the cost of fuel oil is so expensive they   
   >> are now using two electric heaters which keep the place warm   
   >> as long as outside temps are above 20 degrees F.   
   >>   
   >> My concern is that if they lose electricity, which is not   
   >> uncommon on their island, they will lose not only their   
   >> electric heaters but the oil furnace too.   
   >>   
   >> I'm wondering what size generator they would need to keep the   
   >> oil furnace working, and maybe a few lights, fridge, freezer,   
   >> and a few appliances.  Would there be a label on the furnace   
   >> that specifies the power needed to run it?   
   >>   
   >> Any ideas how much juice a small oil furnace uses?  We live in   
   >> the deep South and we use natural gas for heat and for running   
   >> the generator.   
   >>   
   >   
   > There's no real way to tell without either contacting the mfg (which   
   frequently does not work) or measuring the consumption for a few days.  Older   
   units used a lot more than modern units.  Labels on the machines will not tell   
   you what you need to know.    
    The labels generally indicate what size line should be connected to the unit   
   to meet code requirements, and this is often significantly in excess of what   
   the unit might require.  Furthermore, with regard to the refrigerator,   
   although there might be a    
   sticker indicating the annual consumption in kWh, this will not tell you what   
   the maximum draw might be when it starts up.  You might also need to consider   
   a well pump, depending on their source of water.   
   >   
   > However, the electric heaters ratings should be useful in determining their   
   draw, but from what you write, they are not planning to power those during an   
   outage.   
   >   
   > The generator needs to be able to run all the critical appliances, and also   
   handle any startup surge, which can be significant with an older refrigerator,   
   and/or a well pump.  But you don't want to oversize it, as that would be   
   wasteful not only in    
   initial cost, but also in operating costs (less efficient at low outputs).   
   >   
   > It is likely that a 5kW generator would be sufficient for oil furnace,   
   fridge, freezer and some lights, unless there is a large well pump with a high   
   starting surge, or if there are other items not mentioned which need to be   
   considered.   When you    
   mention "a few appliances", this again adds uncertainty to the recommendation.   
   >   
   > Fuel is also a consideration.   
      
   It would be ideal to run the generator on the same fuel you burn to heat   
   the home.   
                   Mikek   
      
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