Just bought a portable air con unit, and wonder if instead of venting
it thru a window, I can vent it do the loft of the house. I have
planned on putting the vent pipe thru' a bit of perspex so I can then
put the perspex across the open window and create a good seal and stop
outside warm air getting back in,
Ah -- there's a flaw there. If you stop the outside air coming
back in, either the aircon unit won't be able to blow hot air out,
or the walls and ceiling/roof of the house will implode as a
vacuum develops in the house;-)
OTOH, if you let the outside air back in, the aircon doesn't work
very well as it's fighting itself cooling the hot air which it's
sucking in.
Notice that of these two options, neither works very well, which
explains why that type of aircon unit doesn't work very well.
when I came up with this loft idea.
Sure, the hot air will get into the loft, but it's boiling up there in
summer anyway.
If the loft is very well insulated and airtight to the rest of the
house, I see no harm in it if there's nothing up there which minds
being cooked). Otherwise, you'll just increase the heat radiated
back from the ceiling and/or the amount of hot air which is sucked
back from the loft into the house.
I was given one of these by another family member who bought it
before realising they don't work. This one has a separate air inlet
grille for the air which is blown out of the house, from the air
inlet grille for the cold air blown into the room. I was able to
make it work quite well by sealing off the former to a second hose
which goes outside to suck air directly into the unit. That way
the inside air is just recirculating. Most of these units don't
have separate air intakes for the two air paths though, so you
can't do this.
