Ductless heat pump air conditioners are very efficient.
- Be sure to have it sized both for the amount of cooling you need and also for the amount of humidity you have.
- The good ductless models have a pump and drain system in them to remove excess moisture, and this has to be sized to fit your climate. When you haven't used your unit for a long time, you need to clear this part by running it on fan-only for a while to dry it out.
Ductless heat pumps are not invisible, so they can be disappointing from an aesthetic point of view.
- LG has one that you can use as a picture frame, but it has a very small capacity unless they've come out with a new model recently.
- Daiken has some very efficient models, but they don't win any beauty pageants.
For more information:
Randy Potter recommends the Fujitsu Halcyon heat pump in his Q&A "I can't afford geothermal. Is an air-to-air heat pump my best option for heating?"
Read Cynthia Phakos's Q&A "How can I remodel my oceanside property for maximum energy efficiency?"