Portable AC Unit In Loft Without Windows - Hose placement?

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Old 07-25-14, 12:39 PM
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Smile Portable AC Unit In Loft Without Windows - Hose placement?

Hiya,

I work from home and I have converted my loft/attic into my office area. This was great in the winter however it is my first summer working up there and the heat is becoming unbearable.

I use my loft area from roughly 1pm - 7pm Monday to Friday. I also live alone, so during this time It wouldn't be a problem if the other rooms downstairs were hot, as long as I could work at a comfortable temperature in the loft space.

I have tried fans which have done nothing, so I am considering purchasing a portable AC Unit. I live in England & we don't have very long summers (if at all) & so I imagine that I will only need this extra measure for a few months of the year.

So my problem: The loft has no windows, and so I'm wondering what would I do with the hose from the portable air con unit? Would it be sufficient to simply point the hose out of my loft hatch and to the rooms downstairs, or does it need to be put out of a window? If so, would it be possible to run an extra long hose down through my loft hatch & out through a bathroom window? (Will the length of the hose make a difference in the functionality or running costs??)

Any help would be extremely appreciated, as I'm feeling at a loss.

Thank you.
 
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Old 07-25-14, 12:55 PM
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It needs to vent to outside in just a few feet. You need a PTAC or ductless split
 
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Old 07-25-14, 01:02 PM
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You could go through the wall much the same way you vent a dryer or at least the way we vent a dryer here. Most here recommend a two tube A/C for efficiency. A one tube one exausts cooled room air the two tube doesn't.

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Old 07-25-14, 01:09 PM
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Hiya,

Thank you for the replies. I should also probably mention that I'm a 23 year old female, living alone and so drilling holes into walls is probably not really an option for me. (I was hoping there might be a solution that I could just do myself.)

- Also, I have tried my best to insulate & soundproof my loft to make my office as private as possible (probably why it is now so hot, as the heat can't escape) & so if i was to put holes or vents into the wall, I'm pretty sure this would mess up my sound insulation.

Can I ask the reason why the pipe can only be very short? Thank you.
 
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Old 07-25-14, 01:23 PM
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Ignoring issues of egress for the moment, what does your hatch consist of? If you pointed the hose down the hatch, it would indeed add heat to the spaces below, but might yield a net reduction in temperature in your loft, as long as the opening for hot air to return upstairs is limited.

While you are here, you should ask about the egress concerns.

Is this space rented or do you own the building?

Bud
 
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Old 07-25-14, 01:33 PM
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Girls can use saws and drills. If cutting or drilling a hole through the wall does not appeal to you I can confirm that young women can get guys to do almost anything you want.

Portable AC units are designed to work sitting right next to a window. Their blowers are not designed to overcome much back pressure so they can't force the air down a long pipe. If you try it it will hurt it's efficiency and you'll get less cooling.

The reason you don't want to just aim the hose downstairs is that all the energy that the AC unit consumes ultimately gets converted to heat. Cold air may blow out the front but out the back you're running a 1'000 watt heater which will soon make your situation worse as all that heat rises up to your office.

If you still want to get a portable AC unit look for one that has two hoses. It will require two holes through your wall but it is more efficient. Single hose units are always blowing out. Air must leak back into the home to replace all the air that the AC is blowing outside so it's essentially sucking in hot outside air through cracks around doors and windows. A two hose unit works more like a window AC where the air inside and outside is not mixed.
 
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Old 07-25-14, 01:35 PM
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The loft hatch is roughly 40cm x 76cm and has a ladder going up to it. (When i'm up there the hatch has to be open for the ladder)

I rent the house but from my parents (Dad has already told me that I don't have a fire escape up there, and I am aware but kind of ignored it.)

& Yeah, that's why I mentioned that I wasn't concerned about the rooms below getting hotter whilst I was up there, but only if this actually meant that my loft would be cooler. If it doesn't offset the heat rising again, then there isn't much point in going ahead. Thank you
 
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Old 07-25-14, 01:41 PM
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This is possibly a silly question, but if I was to go ahead and drill a hole(/s) through the wall, would this cause draughts in the winter & would it also mean that noises from inside my loft would be heard from outside?
 

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Old 07-25-14, 01:58 PM
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In the winter, you could remove the hoses and fill the holes with expanding polyurethane foam (any hardware store should sell it). The foam should seal any voids and give you both sound and weather insulation.
 
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Old 07-25-14, 02:54 PM
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Or just cut out foam plugs from a sheet of Styrofoam for winter and seal with duct tape. Easier then trying to clean out expanding foam the next summer.
 
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Old 07-26-14, 09:01 AM
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Let's try to make this really easy for you. (My daughter is 22 years old, she will never even touch the drill or almost any tools. so I understand your concern, plus you want sound proof, you can not have a hole on the wall) Anyway, (let's try this, won't cut/drill anythng, if it does not work, simply remove it) . Go ahead aim the hose downstair from the 40x76 hatch, seal most of the hatch with a board or blenket or something but leave a hole of 10x10cm for air to come in. Put a strong fan near the output of the hose to blow the hot air out to somewhere else as far as you can. This is not a best/good design, most professionals will laugh at you, but it may work, the point is it is easy to do. Good luck.
 
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Old 07-26-14, 10:31 AM
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I personally would heed your dad's concerns about not having a fire escape.
If you need soundproofing then it must be for something like a trumpet or drum kit right?
If so it might also be the band up there right?
I would not suggest impeding your speedy exit!!!

I have several times used a set up like Ray suggested and it worked quite well.
A dryer vent is a bit smaller than most portable a/c hoses but using a duct reducer didn't affect the unit.

Another thing is that if the rest of the house is not air-conditioned you can easily get away with only connecting the discharge duct and let the air come from the space.
Depending on how the loft is constructed it would be an easy thing to do if you had a gable end to go through.

Some pics of the space might help give you more ideas.
 
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Old 07-26-14, 11:46 AM
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Just to add to my own post. An actual dryer duct vent will onyl work on the discharge side. If you use a two duct model it will not work unmodified on the intake duct.
 
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Old 07-26-14, 12:01 PM
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Good point Ray.........Thanks
I have installed several two pipe portables in offices in our hospital and remove the flapper from the one used for the intake.

A tip for others is that in commercial applications there are many spots where air-conditioning is needed in sub-zero winter conditions.
As long as there is enough air change in the building you can remove the intake hose, block the vent and draw air to cool the condenser from the room.
 
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Old 07-28-14, 06:38 AM
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Thank you for the replies, I really appreciate the help

I'm still not convinced on drilling holes into any of the walls, but the idea of placing a cover over the loft hatch with a hole for the hose & a fan on the other side would definitely be doable. Also this will only be a measure that I need to use over summer, as I live in England & most of the time the temperature is cool enough.

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I've attached photos for reference, you can see the loft hatch & ladder.

Sound proofing is due to my job x
 
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Old 07-28-14, 07:12 AM
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What is on the other side of the end wall (triangle) in the third picture.
 
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Old 07-28-14, 07:25 AM
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I'm not 100% sure what you mean, but behind my iMac & wardrobe is a painted brick wall that goes to the outside of the house. The other three walls (everywhere where there is the gold wallpaper) have been boarded out with wood & have more attic space behind them. The roof has been sprayed with foam insulation & then boarded with pvc panels.
 
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Old 07-28-14, 08:22 AM
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"I'm still not convinced on drilling holes into any of the walls, but the idea of placing a cover over the loft hatch with a hole for the hose.... "

If you are willing to try the above, make sure you leave a gap or hole for air intake too in addition to the hole for the hose. That ladder's area opening should serve the air intake purpose.
 
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Old 07-28-14, 11:14 AM
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The other three walls (everywhere where there is the gold wallpaper) have been boarded out with wood & have more attic space behind them.
Venting a portable A/C tothose areas might work and if you have a gable vent you can put a box fan against that would help keep the temp of the area on the other side down.

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