View Single Post
  #7   Report Post  
Andrew Gabriel
 
Posts: n/a
Default whole house DIY-ish air con ?

In article ,
John Rumm writes:
wrote:
The difficulty with ducting is that it would need to be two way. Air con
is not just about pumping cold air into the room. You also need to
extract the warm moist air since it is the dehumidification that makes a
big difference to the comfort level and not just the temperature.

Getting two sets of insulated ducting to/from each room is going to be
harder.


US systems feed into each room, but have a smaller number of common
return ducts, typically from the hallways, kitchen, and bathroom.
Actually, I don't recall any feeds into the kitchens and bathrooms
either -- probably just keep these at negative pressure to avoid
heat, moisture, and smells invading rest of house.

A split system that uses several internal air handlers connected to a
single external condensor would be a simpler job to install.


When I looked at these systems for an office, admittedly some 8
years ago, the multiple evaporator systems could only have a single
thermostat. That made them fine for very large rooms, but not for
multiple rooms. Things maybe different with them nowadays.

I did look into options for doing this (when I had the roof off the
house seemed like the ideal opportunity!) but could not find any multi
way split systems that were avaiable for self install (one or two way
units were available - but four way seemed more elusive). The


I don't know where the crossover point is, but multiple internal
units are more commonly done with fan coil units running from
chilled and heated water circuits. A single outdoor chiller is used
to create the chilled water to drive them (and sometimes the heated
water too, particularly for buildings which need some parts cooling
and other parts heating at the same time).

--
Andrew Gabriel