Jim & Wilma Posted November 7, 2020 Report Share Posted November 7, 2020 A friend asked the other day about heating efficiency of electric versus propane. I thought the attached Heating Cost Comparison spreadsheet may be useful to others. Your cost of fuel and system efficiencies may be different, so you'll want to update those cells for your use. For my engineering friends, I did take some liberty giving heat pumps an efficiency rating. Obviously a system can't be more than 100% efficient. Heat pumps are typically rated in Coefficient of Performance (COP) units which in my example would have a COP of 2.4 or with great liberty 240%. Heating Cost Comparison.xlsx Quote Jim & Wilma 2006 Travel Supreme 36RLQSO 2009 Volvo VNL730, D13, I-shift, ET, Herrin Hauler bed, "Ruby" 2017 Smart Class of 2017 Link to comment Share on other sites More sharing options...
docj Posted November 7, 2020 Report Share Posted November 7, 2020 (edited) 4 hours ago, Jim & Wilma said: Heat pumps are typically rated in Coefficient of Performance (COP) units which in my example would have a COP of 2.4 or with great liberty 240%. As a clarification, the COP of a heat pump will decrease as the outside temperature (thermal reservoir) falls and will reach 1.0 at roughly zero degrees F. However, as the temperature falls below 32F water vapor condensing out of the air will form ice on the outside coils and it will be necessary for the device to "reverse" itself to melt the accumulation or to derate itself. I believe some (all?) Dometic heat pumps reverse themselves like residential systems. From what I've read my new Coleman Mach8+ heat pumps derate themselves in some manner at temps below 40F. One thing that varies among heat pumps is the indoor coil temperature. A long time ago we had a residential heat pump which produced air on the indoor coil that felt cool to the touch (it was below skin temperature). It was dreadful. Our new Colemans produce air that feels warm! We've been using them at night for the past couple of weeks; we are very pleased. Edited November 7, 2020 by docj Quote Sandie & Joel 2000 40' Beaver Patriot Thunder Princeton--425 HP/1550 ft-lbs CAT C-12 2014 Honda CR-V AWD EX-L with ReadyBrute tow bar/brake systemWiFiRanger Ambassador Follow our adventures on Facebook at Weiss Travels Link to comment Share on other sites More sharing options...
GlennWest Posted November 7, 2020 Report Share Posted November 7, 2020 We have seen 40's at night. Our mini splits have kept us comfortable. Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
Randyretired Posted November 7, 2020 Report Share Posted November 7, 2020 There are heat pumps available that can heat at temperatures to - 15F. Our minisplit was keeping us comfortable when the outside temp was 30F and was drawing about 550 watts. Not all heat pumps are the same. There are some very efficient models available and there are specifications that detail that efficiency for comparison. It appears our minisplit is around 3 to for times more efficient than electrical resistance heating. Quote Randy 2001 Volvo VNL 42 Cummins ISX Autoshift Link to comment Share on other sites More sharing options...
lappir Posted November 7, 2020 Report Share Posted November 7, 2020 25 minutes ago, GlennWest said: We have seen 40's at night. Our mini splits have kept us comfortable. My Mini Split worked very well for me in Edmond, OK. last winter. Several days that didn't get out of the 20's and nights in the teens. My Coleman Mach would have been blowing very cold air, but the mini split has 80+degrees all the way to the front of my trailer with the unit at the opposite end. I have a wall unit in the bedroom, but it most of the time makes it too hot when it blows air so I keep it off while sleeping. The reversing during the coldest times is quite a sound. I have never been outside near the ODU when it's happened, but it's very noisy. I recommend putting the ODU at the opposite end of where you sleep if possible. Rod Quote White 2000/2010Volvo VNL 770 with 7' Drom box with opposing doors, JOST slider hitch. 600 HP Cummins Signature 18 Speed three pedal auto shift. 1999 Isuzu VehiCross retired to a sticks and bricks garage. Brought out of storage the summer of 2022 2022 Jeep Wrangler Sport S Two door hard top. 2007 Honda GL 1800 2013 Space Craft Mfg S420 Custom built Toyhauler The Gold Volvo is still running and being emptied in July. Link to comment Share on other sites More sharing options...
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