What space heater do you have?

Hi,

Heat pumps work by extracting heat. This heat pump and every other heat pump extracts latent heat from outside the RV and pumps it to inside the RV. I'm glad it works in temperatures down to the teens.

Extracting heat from inside the RV and returning the heat to the RV would be a perpetual motion device.

rgatijnet1 wrote:
Unlike roof top heat pumps, the single hose heat pump draws air from the inside of the coach, and it will work just fine no matter what the outside temperature drops to. We have used ours in locations where the outside temps were in the teens.

Caframo heater made specially for RVs. Model 9206. Practically impossible to tip over. We run ours from the inverter while traveling.

They even have a freeze protection setting for winter storage.

I won't use anything else in my RV.

Just type Caframo 9206 into Google search.

rgatijnet1 wrote:

JumboJet wrote:
Heat pumps become inefficient when the temperature gets real cold. I have had heat pumps in my home for 47 years. Most homes that have heat pumps have backup heat strips. I can tell by watching the meter spin when those strips are activated.

That is why the portable heat pump that I referenced is a single hose unit that draws air from the INDSIDE of the coach and exhausts the cold air out the single hose to the outside, while blowing the warm air in the coach. It is unaffected by outside temps and maintains it's efficiency all of the time.
They do make portable DOUBLE hose heat pumps that draw air from the outside and also exhausts air to the outside. These units are like a rooftop RV heat pump or a residential heat pump with a pad mounted compressor.
They also make ground coupled heat pumps that are connected to the earth, or a body of water, that will continue to operate efficiently in all kinds of weather, without heat strips.
Technology is improving all of the time and what was happening 10 years ago is not longer relevant.

I went and took a look at that A/C - Heat Pump. That really looks interesting.

OhhWell wrote:

rgatijnet1 wrote:

JumboJet wrote:
Heat pumps become inefficient when the temperature gets real cold. I have had heat pumps in my home for 47 years. Most homes that have heat pumps have backup heat strips. I can tell by watching the meter spin when those strips are activated.

That is why the portable heat pump that I referenced is a single hose unit that draws air from the INDSIDE of the coach and exhausts the cold air out the single hose to the outside, while blowing the warm air in the coach. It is unaffected by outside temps and maintains it's efficiency all of the time.
They do make portable DOUBLE hose heat pumps that draw air from the outside and also exhausts air to the outside. These units are like a rooftop RV heat pump or a residential heat pump with a pad mounted compressor.
They also make ground coupled heat pumps that are connected to the earth, or a body of water, that will continue to operate efficiently in all kinds of weather, without heat strips.
Technology is improving all of the time and what was happening 10 years ago is not longer relevant.

There is a small tag I would like to add on that. The single hose portable heat pumps do work as you say but there is one small drawback and that is that while ejecting the cold air outside, they create negative pressure in the motorhome and that draws cold outside air back in. It reduces the overall efficiency some but I think you would still come out ahead of a traditional resistive heater.

In operation most of the air drawn in is filtered and then passed over the coils to give up the cold and then is blown back out in to the coach as warm air. There is a small amount of air that is drawn in at another vent opening to cool the compressor and heat exchange coil and that air is what is blown outside as exhausted cold air. There is some outside air that is drawn in during operation but that is necessary to insure that the inside air does not get stale. A sealed compartment is an unhealthy compartment.

rgatijnet1 wrote:

JumboJet wrote:
Heat pumps become inefficient when the temperature gets real cold. I have had heat pumps in my home for 47 years. Most homes that have heat pumps have backup heat strips. I can tell by watching the meter spin when those strips are activated.

That is why the portable heat pump that I referenced is a single hose unit that draws air from the INDSIDE of the coach and exhausts the cold air out the single hose to the outside, while blowing the warm air in the coach. It is unaffected by outside temps and maintains it's efficiency all of the time.
They do make portable DOUBLE hose heat pumps that draw air from the outside and also exhausts air to the outside. These units are like a rooftop RV heat pump or a residential heat pump with a pad mounted compressor.
They also make ground coupled heat pumps that are connected to the earth, or a body of water, that will continue to operate efficiently in all kinds of weather, without heat strips.
Technology is improving all of the time and what was happening 10 years ago is not longer relevant.

There is a small tag I would like to add on that. The single hose portable heat pumps do work as you say but there is one small drawback and that is that while ejecting the cold air outside, they create negative pressure in the motorhome and that draws cold outside air back in. It reduces the overall efficiency some but I think you would still come out ahead of a traditional resistive heater.

JumboJet wrote:
Heat pumps become inefficient when the temperature gets real cold. I have had heat pumps in my home for 47 years. Most homes that have heat pumps have backup heat strips. I can tell by watching the meter spin when those strips are activated.

That is why the portable heat pump that I referenced is a single hose unit that draws air from the INDSIDE of the coach and exhausts the cold air out the single hose to the outside, while blowing the warm air in the coach. It is unaffected by outside temps and maintains it's efficiency all of the time.
They do make portable DOUBLE hose heat pumps that draw air from the outside and also exhausts air to the outside. These units are like a rooftop RV heat pump or a residential heat pump with a pad mounted compressor.
They also make ground coupled heat pumps that are connected to the earth, or a body of water, that will continue to operate efficiently in all kinds of weather, without heat strips.
Technology is improving all of the time and what was happening 10 years ago is not longer relevant.

Heat pumps become inefficient when the temperature gets real cold. I have had heat pumps in my home for 47 years. Most homes that have heat pumps have backup heat strips. I can tell by watching the meter spin when those strips are activated.

Oops!

rockhillmanor wrote:

rgatijnet1 wrote:

pianotuna wrote:
Hi,

Watts don't care what type of heater they are powering--and they are all the same total heat. However, radiant heaters warm what they are pointed at first--and then the heat from the warmed object radiates to the room.

....

Those same watts powering a heat pump will put out almost twice the BTU's of heat than the best radiant heater.

Radiant heat is not very efficient when compared to other methods of producing heat.....

There it is! Watts versus BTU's.

In regards to 'space' heaters. Do all 1500 watt space heaters put out the same BTU's of heat? I don't think I ever saw BTU's rating on the outside box of space heaters.

I now know that on vacuum cleaners they purposely do not put the amps on the outside of the box so you can't compare them.

To convert from watts to BTUs with a radiant heater, multiply the number of watts by 3.413. 1500 watts X 3.413 equals 5119 BTU's of heat.
Some heaters give you that information and some do not.

Hi rockhillmanor,

Yes, if they are resistance heaters, 1500 watts will put out an identical number of btu's. However, the name plates on the heaters are notoriously unreliable. I've had 1500 watt heaters that really did only 1200 watts, and units that were labeled 1500 that did 1597 watts.

rockhillmanor wrote:
In regards to 'space' heaters. Do all 1500 watt space heaters put out the same BTU's of heat? I don't think I ever saw BTU's rating on the outside box of space heaters.