I purchased 3 of these around 8 months ago, mainly the purpose was to provide energy efficient room heating in 3 of our bedrooms. On special at Good Guys, with a$100 rebate they came in at around$750 each. Installation was just under$3k however as I wanted 2 on wall brackets and 1 was on the deck. Heating mode is good, although they obviously take a fair time to get the room at temperature you want. Due to the excellent 6* efficiency the answer here is to keep them on 24/7. Unfortunately the heat mode is quite noisy, especially if you live s omewhere which gets real cold(I live in Canberra region) as the defrost cycle will come on and makes a strange sound like water and gas gushing all of a sudden. In addition the units do vibrate quite badly when in heat mode as well. That being said I'm not unhappy with the units but I am surprised how noisy they are in heat mode. 2 of our units are mounted on the outside of our 1960's weatherboard home(Oregon timber frame) and they do vibrate at points in the cycle although not too badly. I did have to refill a few small cracks in plaster wall from the vibrations, although these were pretty minor. I'm happy I mounted those two on the walls and not on the ground outside the house though as they are protected from the elements better. Fan mode is excellent, very powerful when needed. Its now the summer and the cooling is very good and pretty quiet. I haven't noticed any noises really. The main plus for these units has to be the energy efficiency which is 6* for heat mode and 5.5* for cooling. One thing to note is that the standby power usage is pretty high so if your going away or not going to be using the units for a while have them on isolation switches and turn them off
