air con vent into loft or airing cupboard?

[Rob]

Hi

I live in a top floor flat. The rear rooms which I use as bedroom/office get really hot as the sun is beating on them all day long.

Ive been looking at small air con units. Ive been told that its no good putting the vent out of an open window and this doesnt look good either.

I cant put a vent hole through the wall to the outside as the lease wont allow it. I wondered if its OK to vent into the loft space or the airing cupboard? The loft is just used for storage and in the summer it gets like a suana up there any way. The airing cupboard is just on the other side of the wall of my office so making a vent hole into it shouldnt be difficult.

Any advice or suggestions would be very welcome.

Thanks

Rob

[John Hearns]

The portable single units, ie. the ones which use a flexible hose to vent out of the window, should come with a flat piece of plastic. you close the window onto this. The plastic piece has an oval shaped hole, which the hose clips onto. This assumes of course that you have window which opens in the fashion of a sash window.

These type of units work just fine - I'm sitting in front of one now.

I do agree what a proper indoor/outdoor unit, joined by pipes would better and neater. But if all you want is some cooling on these hot days of the year, try a portable unit.

[Pecanfan]

If you're renting the place personally I would just vent it out the window. If you're after a more permanent solution get a vent slate fitted on the roof and plug into that. As one of the other posters mentioned, most half decent portable air-con units come with an attachment for sash-type windows, however we've found it works just as well dangling the hose out the window. These things kick out serious heat so I wouldn't be too keen on venting into a sealed space. Ours also collects around 4L of water per day!

Andy

[Rob]

Thanks for the info Andy.

Roof vent slate is a great idea but isnt poss. I'n not renting but the lease wont allow it.

I'll just hang a hose out the window - but I dont have sash windows. Mine are double glazed units which are hinged at the sides so the bottom opens outwards. Is that a problem? I guess as long as I dont get any blow back it should be OK shouldnt it??

I didnt consider how much heat they have to dispose of until now.

But at the mo my office with sun glaring at me through blinds plus PC and monitor belting out loads of heat = 36C(97F) in the room!!!!! And thats with two fans on. PC has been groaning about the heat too. Have got a fan blowing on it now!!!

I'm meltinggggggggg!!

Thanks

Rob

[PC Paul]

You want an external blind if you can possibly manage it. Internal blinds just absorb the heat and reradiate most of it into the room.

Are you on the ground floor? Even an opaque sheet hanging outside the window will drastically reduce the heat coming in. Or get mirrored film on the window?

[Sparks]

You could get a split type unit, this has two units, one of them goes outside (Normally you can hook them on two small screws, screwed into the external wall)

The are much better then the ones with a hose, as they cool the air, without throwing any of it out the window (The ones with a hose throw air from inside, outside, this causes (warm) air from outside to come in, to replace it.

You do still have to have a window open, but not as much as a hose type.

I have one of these, and it works really well.

external unit is actually white (well mine is)

...and don't even think of getting an evaporative "Air Cooler" that only needs power and water without any venting, as in my experience, they are useless, and only make the room feel humid

Sparks...

[John Rumm]

Try to get the hose out with as little opening as possible (you can always use an old blanket to seal round the pipe to stop too much air getting drawn in through the window). One of the limitations of the nonobloc units is they expel air from the room - hence it forces more warm damp air to be drawn in from somewhere.

Well if you have a 1kW unit it will be shifting heat from the room at a rate of 3kW, and then adding its own consumption to the output. So the output will be like a 4kW fan heater!

Cutting down the solar gain is one big step you can take to reduce the amount of heat getting into the room. Window film would probably help and be easy to apply.

The fans themselves will add yet more heat. You could try opening the window and having one sat close to it pointing out so that it extracts some of the hot air rather than just warming it up a bit more an circulating it.

Remember also that while fans may make you feel cooler, they are not going to do much to help the PC!

On the subject of air con units, you can get some portable split units where you hang the external unit out of a window (over the windowsill) and then mostly close the window (there is narrower bunch of cables/pipes that connect the two bits). These have advantages over the monobloc units in that they are more efficient and much quieter in the room.

[T i m]

Am I right in thinking that the fans will actually add to the temperature (motor heat) and it's only the chill factor that makes us feel better?

PC has been groaning about the heat too. Have got a fan blowing

Just out of interest (when it all cools down later / whenever) taking the PC out and making sure all the fans / vents are clear. I had a friend on the phone first 'reallly' hot day this year saying his PC was locking up. When I went round there the CPU heatsink was completely bunged up with fluff! (If it is all bunged up an ailine (carefully), a vacumn on blow or air blower can are very handy).

Soak yer T shirt in cold water, wring it out, put it back on *then* sit in front of the fan! ;-)

All the best ..

T i m

[Huge]

Can you disconnect the external unit from the internal? I already have a duct through the wall for the vent on a monobloc unit, and I'd like to pass the hose through that...

[Adrian C]

Don't do this too often. You may learn what human spontaneous combustion is all about when your brain decides it's had enough trying to restore overcooled areas back to normal. Or at the very least other nasty problems.

(disclaimer: or so I'm told....)

-- Adrian C

[Sparks]

Yes, they have self sealing connections, just undo them, keeping the pipes straight, and you should be just fine :-)

The manual for it is here

a look on page 7

Sparks...

[Huge]

Excellent.

Thanks, I found that after posting. Apologies - I should have RTFM.

[T i m]

This is England Adrian .. get past the next couple of days and it will be snowing again! ;-)

You may learn what human spontaneous combustion

Hey, the guy was melting already how much worse can it get! Out of interest, would these 'nasty problems' be any worse than being overheated in the first place? I wouldn't have thought (but will quickly stand corrected) that there would be that much cooling in the above (say compared with a sauna then a plunge pool). The cooling effect uses the 'latent heat of vapourisation' (isn't it) from the surface and the 'cold' would then have to conduct through the (wet) fabric to the skin (not sure how efficient that would be). At the same time the body would be heating the wet shirt up?

Isn't instant human combustion to do with high levels of phosphor or summmat?

All the best ..

T i m

[T i m]

That's what I did and all is still ok ;-)

All the best ..

T i m

[Pete C]

Hi,

Are the only windows on the side that faces the sun?

I've found a good way of blocking heat from coming through blinds is some sort of reflective material, like a foil car sunshade, foil backed beach mat (both from a pound shop), or space blanket.

Also try and get as good a through breeze as possible, ideally so it's also blowing out the window facing the sun.

cheers, Pete.

[manatbandq]

A little, depending how efficient they are.

Increased airflow reduces the thermal resistance between the thing being blown on and the air. At a given air temperature, blowing that air at an object generating heat will cool the object. That's why CPU heatsinks have fans. The thermal resistance from the heatsink to the air (and thus from the silicon to the air) is reduced and the silicon will stay cooler than it would otherwise. Similarly when you stand in front of a fan your core body temperature will reduce as the thermal resistance from skin to air is reduced.

MBQ

[Adrian C]

Yep. William Hill odds for Snow on Christmas Day, anyone?

Oh I don't know, INAMP. Going from overheated immediately to overcooled is a problem, it puts strain on the body's blood pumping system - which may be something not good if other cardiac problems exist. Running your cold water over your wrists may be a temporary solution that might make feel good, but placing a heat pump there (or in your hat etc...) would be a signal for the brain to start things compensating.

Doing it slowly is not a problem, and googling "heart attack" and "air conditioning" reveals a clear benefit in installing these systems.

I wouldn't have thought (but will

Yup. Laws of Physics helping out Laws of Nature by making sure wet T-shirt owners don't over do it!

I went off to look at some web references. Found the topic so gruesome that I apologise for raising it up in jest(!)

-- Adrian C

[John Rumm]

You also benefit from the ability to secrete moisture which in turn the air flow will help evaporate. This gives living bodies extra cooling in an air flow not available to heatsinks etc.