Question>: I was reading your Winter
Un-Wonderland page, and wanted to make a post about heating. I am looking into buying a heat pump with AC which is at least 2 to 3 times more efficient than a standard electric heater (any electric heater).
However, one big issue to me is the RV AC/Heat pump manufacturers – Atwood and Dometic – won’t tell me how efficient they are. I have inquired with Dometic and Atwood for a few weeks now and they state that the Coefficient of Performance (COP) data is “unavailable”.
In contrast other manufacturers give you COP. For instance, a standard GE 9,000 btuh heat pump unit for house or Motel room, window and PTAC, runs at a COP of 2.9 and 3.7 respectively. The problem for RVers lies in where do you mount a 110 VAC window unit (finding a window that can fit one). And with the PTAC, most – if not all – are 220 VAC and you need a much bigger hole (16×42)to install.
If anyone out there can get this COP (btuh output vs. Watts input) data for the RV heat pump units please post it here.
Answer: Your question about a COP for an RV A/C-Heat pump is a first for us. We’ve done some searching online and, like you, have not gotten any hits specific to Dometic or Atwood A/C units for RVs.
However, here is what my calculated number is for pur specific Dometic A/C unit with heat pump.
Our AC/heat pump units are built in roof-top and we have been happy with their performance. We have a Duo-Therm Penguin model # 63515.321 (manufactured in 2002).
Compressor rated load amps are 12.4 at 115 volts
Fan motor rated load amps are 3.1 Watts = 1782.5
We’ve looked at the formulas for calculating COP and they seem to be dependent on temperature, so it is a moving target. Perhaps this is why you have not been able to get a direct answer from Dometic or Atwood.
If you have a simple way of converting my numbers to COP then you may have a start.
Maybe others can provide further information.