Hello, I am a student who is working on designing the cooling and heating systems for a house to compete in the Solar Decathlon competition (http://www.solardecathlon.gov/index.html).   I have recently learned about the Daikin Altherma system and I would like to know if anyone has had any experience with installing or using one of these systems.  The system I am interested in uses the Hydrobox to heat both the hot water and to heat or cool a fan coil unit which I believe (and please correct me if I'm wrong) can be combined with a ducting system to provide heating and cooling for the house.  I just have questions on its reliability and any obstacles that I need to consider, such as its energy usage which is heavily monitored during the competition.  This is the first time I have designed a house so I look forward to hopefully being able to talk to some professionals. 

I've got a Daikin Altherma in operation. It's very well made and we installed it because it has a very efficient inverter based drive. It drives a very low temperature concrete floor radiant system. It also heats the domestic hot water.

Oh awesome, I have been reading up on it since I posted this question and it seems like that inverter function makes sure it saves power by not running at full capacity all the time, am I correct? Also it seems like it cannot do both cooling and hot water at the same time, but has to switch between one or another? Can you help me in understanding whether this is true or not?

Also I am aware that it can be combined with a radiant system, is yours cooling and heating, as in, do you have the reversible hydrobox heat pump?

Yes, all correct. We can do both heating and cooling because we wanted the ability to chill some of the radiant areas, although it now looks as if we'll probably not use the cooling function except for experimentation. I haven't fully investigated the control functions to see how the switchover from heating to cooling is accomplished or how it handles domestic hot water production while in chilling mode.

I believe you can access an operation manual by noodling through the Daikin Altherma website.