Extending portable A/C vent hose

[morqthana]

I've bought a portable a/c unit (DeLonghi, if that matters). I know when I bought it that it would have a stupidly short vent hose, just like it would have a stupidly short mains lead, but I thought "no problem - I'll buy an extension piece.

But no. Mr DeLonghi he say

"We do not recommend that you lengthen the exhaust hose as this can damage the product."

When I looked into this, I found

https://www.doityourself.com/stry/how-to-extend-a-portable-air-conditioner-hose

and several other similar warnings. But I wondered if a lot of it was AI regurgitating incorrect info or other AI. I know that makers have to cover themselves - they don't know if someone is going to gaffer-tape 100m of vacuum cleaner hose to it, but really, the volume and velocity of the air coming out of the hose is so small that I can't see how the fan could be compromised by a few more m of the same size & type of hose.

Does anybody know what the truth is?

 

[Wayners]

My first portable air conditioning unit I extended the pipe with white concertina pipe but the turbulence and air pressure causes a strain on the fan.
Air conditioning units use a centrifugal fan which creates an air pressure which pushes a volume of air along the pipe at pressure.
If you extend the pipe you can cause more pressure which puts the strain on the fan which eventually will break it.

Your never want to use a reducer or squeeze the pipe through a gap causing a back pressure.
I have extended my current air conditioning unit using smooth 110mm soil pipe. So far that's worked well

 

[morqthana]

My first portable air conditioning unit I extended the pipe with white concertina pipe but the turbulence and air pressure causes a strain on the fan.
Air conditioning units use a centrifugal fan which creates an air pressure which pushes a volume of air along the pipe at pressure.
If you extend the pipe you can cause more pressure which puts the strain on the fan which eventually will break it.

That's the concern - I'm just wondering how much of a genuine one it is.

Your never want to use a reducer or squeeze the pipe through a gap causing a back pressure.

Well, I would use the same size pipe, obv.

I have extended my current air conditioning unit using smooth 110mm soil pipe. So far that's worked well

I know that smooth rigid is best, but it's a tad impractical. If I do it I might see if I can get flexible smooth bore.

 

[foxhole]

Really needs a vent outlet thru wall unless you have sliding window or door which most seem to be designed for. The outlet kits don’t really work with conventional hinged windows.