Originally Posted by Iggy
Heat pumps are more inefficient as the outside temps drop closer to freezing to apoint that it is just a waste of electrical energy to produce very little heat. In a house with a larger condensor it is more efficient but with a small RV unit the condensor is way too small to make it worth while to use a heat source.
Drawbacks of air-to-air heat pumps are:
- loss of efficiency as temperature decreases below 6–7ºC
- higher initial purchase and installation cost than portable heaters
- air distribution is by fan, which can cause draughts and noise
- space is needed to install larger exterior consensor
Iggy you are correct, But Rick gave a great explanation on how they work. When the heat pump can not keep up a heat strip should kick on. A heat pump without a strip heat is not going to work when the temp outside drops to be unacceptable the strip should kick in auto if your stat will not reach the set pt. most stats have a 2 to 4 degree band. The whole point is that you can turn on the emergency heat which activates the heat strip (cheap heat). In commercial apps. you have a air handler then when you call for heat the electrical strips turns on, which creates your heat otherwise it is just cold air 24hrs. aday. I had a wildwood LE trailer. The ac unit roof top (not a h/p) came with a plug in heat strip connection as an option. Also a propane furnace. If I wanted heat from the roof top unit the heat strip and blower came on only. The same concept of cheap heat. The only thing is that you just had to buy the strip and plug it in where your filter is. All wired and set up already. The only thing is that strip heat pulls a lot of amps. So maybe I would have been able to put a 4kw strip in. Not very much but my trailer was only 19' at that time........ My new Rookwood doesn't have that option.....