Domestic a/c

[Ken_Code]

Funk said:

I looked into water-cooled ones; they were really expensive, bulky and apparently very wasteful of both water and electricity...?

What system do you have - sounds like something different?

I can’t remember, sorry, I stuck it in for the tenants a couple of years ago.

The main unit is small enough to fit inside a kitchen unit and then uses very small-bore pipes to take the refrigerant around to the wall units.

[Simpo Two]

Phil. said:

This guy fitted mine and he’s very good. Worth a call and I believe he travels for work:

https://www.facebook.com/aircon4home

Thanks; I've dropped them a line though being in 3-4 counties away I doubt they'll go for it.

C n C said:

I'm not an expert, but I can see why they would be concerned about return ducts, and where the air would go.

With a split system, the air remains in the room and is recirculated, so the cooling effect of the unit is effectively cumulative. It's one of the reasons they are far more effective than the portable units as those continually vent hot air outside, but therefore draw in warm ambient air to replace it.

Why can't a portable unit recirculate the air? I assumed they would, just as a fan heater does.

C n C said:

With a ducted system as you've described it, just having "input" ducts introducing cold air would fill the room and cool it, but would be very inefficient, as if you're continually pumping cool air into the room, you're also forcing (cool) air out of the room through cracks around the door etc.. I'd also imagine that if the room was relatively well sealed, it would put an increased load on the FCU as it tries to pump air into a closed container (your room).

I'll explain the layout of the house. The lounge is connected to the hall/stars/landing by an arch; there is no door, no sealed box. And my bedroom door is always open so the relevant parts of the house are all open to each other.

C n C said:

ETA - I'd also imagine that the loft space would be far from the most ideal place (from an efficiency point of view) to put the FCU, if our loft is anything to go by, as it gets incredibly hot in sunny weather - much warmer than the outside ambient temperature where a conventional split unit condenser would be.

Yes, the loft does get bloody hot in summer - but I thought the evaporative bit was on the outside (a north wall). The device in one of the quotes was https://www.daikin.co.uk/content/dam/dauk/document...

It's all very confusing...

[Simpo Two]

PS I forgot to add that this post does seem to put the conventional split system back in the frame. One installer said he didn't think it would work, another said he thought it would... not convincing evidence to gamble £Ks on... and I also have my desk at he north end so don't to be in a draught...

C n C said:

I don't know if it's any help, but when we put our system in, the 3.5kW internal unit is in a room with an extension which is 30 feet long, and 15 feet wide. The internal unit is mounted on one of the "side" walls, in the extension about 2 feet away from the patio doors, which are at the end of the extension, so in theory far from an ideal placement, as it's right at the end of the 30 foot long room, and facing across the room rather than in line with the longest axis.

Our internal units have variable direction vents, so can be directed to left/right, and down/straight in front.

Setting the unit in this long room to direct the air to the side and straight (rather than down), it has no problem at all in cooling the whole room, and doesn't cause an uncomfortable cold draught. I know this as I usually sit roughly mid way along the room on the opposite side to the unit to watch tv, so am effectively directly in the firing line so to speak.

To be honest, once the a/c has been running in a warm room for 5-10 minutes, and the temperature drops, the fan speed automatically reduces and you hardly notice it is even on.

If your problem with a split system is that in one 25 foot room, the only location for the wall unit would be on one of the end walls, I personally wouldn't see this as a problem. A wall mounted unit set to blow straight ahead (rather than left or right) and as high as possible (rather than down) should have absolutely no problem in keeping the room at a comfortable temperature, even if it is at the "cold" end of the room, away from the south facing window.

For reference, because this was the largest of the 4 rooms we put a/c units in, it got a 3.5kW wall unit, whereas the others got 2.5kW units.

[Sheetmaself]

Simpo Two said:

I'm looking at window film this afternoon, though it will be a few hundred £ and I'm not sure how much cooler it will keep the rooms.

The two rooms both have south and west walls so in periods of hot weather they soak it up like a storage heater.

Edited by Simpo Two on Friday 17th May 17:17

We have the window film, went for the darkest we could without it looking like the house has sunglasses and we didn’t want the mirror look either so I accept we limited ourselves. But whilst it has made a slight difference I think we both wish we had waited and just gone AC route.

That said it is a large south facing window.



The unit you can see is an air cooler and so far it seems ok. Certainly won’t make really hot days much better but on a low 20 day like today it helps quite a bit.

[bogie]

We upgraded from some portable units to Mitsubishi splt units a couple of years ago and the difference is fantastic. They take minutes to cool the room down (or warm it up) and are vastly more efficient when down to temp. We have a single unit outdoors serving 2 rooms above/below in one part of the house and another separate unit at other end of the house.

If you are in Lincs or East Midlands, Sth yorks then I can recommend https://www.josa-ac.co.uk/ very reasonable and professional install. They do ducted systems as well (through roofspace) if you dont want the indoor units on show.

[Dr Mike Oxgreen]

For a bedroom, I wouldn’t recommend air conditioning of any kind. Too noisy.

You can feel cool without air conditioning. A ceiling fan is much cheaper to buy, much much cheaper to run, and almost silent in operation - certainly quiet enough to have it running all night. And you can fit it yourself.

I fitted one of these in place of the existing light fitting in the bedroom. It’s bloody brilliant, and rarely do we need to use it above its minimum speed. Because the blades are large, they don’t need to spin fast and therefore create none of the noise of a pedestal fan. There is a very faint hum from the motor, but not very noticeable. And the air movement is really even with no buffeting.

It gives 80% of the benefit of aircon, for a fraction of the cost and with virtually no noise.

In fact we were so impressed with it that Mrs Oxgreen wanted one in her study, so I ended up buying and fitting a second one.

[shirt]

Simpo Two said:

shirt said:

The main advantage is looks. No boxes on show, just the grilles. I’m not sure how a retrofit would be handled into a typical uk house construction though and the complexity / rework required is likely what is putting off suppliers from quoting. I’d have thought you’d need a builder or plasterer / decorator to work with the system design to advise on that.

It's actually very simple - the FCU would be in the loft with a short duct through the upstairs ceiling to the bedroom, and another duct (or the same one with a flap valve) descending vertically through a built-in wardrobe to the centre of the lounge/diner directly below.




The (potential) installers seemed overly concerned with control systems, talking about return ducts and fretting over where the air would go. But I'm not demanding perfect climate control, just a simple way to turn the unit on/off/up/down which could be wired or wireless. I could make the holes and fit ducting myself, I just need someone to specify and install the equipment.

Yea those runs look simple. I’m no expert, but do you know anyone in m&e who could spec it for you? These are the kind of questions I usually ask my mate and he tells me what to do.

[Phil.]

Dr Mike Oxgreen said:

For a bedroom, I wouldn’t recommend air conditioning of any kind. Too noisy.

We have air con in bedrooms in UK and Spain. At night we use the ‘quiet’ setting or just turn fan down. It’s quieter than any portable fan and much cooler than a ceiling fan.

[mrpbailey]

Dr Mike Oxgreen said:

It gives 80% of the benefit of aircon, for a fraction of the cost and with virtually no noise.

Really?? 80% of the benefit of air con by blowing warm air around?!

I replaced our portable air con unit with a 2 way split system 3 years ago, one of the best changes done on our house! Almost silent on quiet mode at night.

[Danns]

Simpo Two said:

It's actually very simple - the FCU would be in the loft with a short duct through the upstairs ceiling to the bedroom, and another duct (or the same one with a flap valve) descending vertically through a built-in wardrobe to the centre of the lounge/diner directly below.




The (potential) installers seemed overly concerned with control systems, talking about return ducts and fretting over where the air would go. But I'm not demanding perfect climate control, just a simple way to turn the unit on/off/up/down which could be wired or wireless. I could make the holes and fit ducting myself, I just need someone to specify and install the equipment.

I’ve spent a fair bit of time looking at a ducted system this year, I’m not ready for it yet, but will be installing it over the next couple of years.

I’ll be doing it myself, not detail to hand but high level I think where I’ve got to is a Daikin ducted system with a Eazyzone manifold which has 5 x 150mm dampers on, all controlled from rooms stats.


I’m somewhat sure you want to be putting both a supply and return duct to each room, to overcome the issues mentioned above - can get a 5 x 150mm plenum to go on the Daikin indoor unit.

Added complication for me - I’ve got to try squeeze it all into the eave space as already have a room in roof loft conversion (although I plan to redo it). Also need to navigate under the loft conversion for a couple of the runs. Soil stack handily close tho for the condensate drain.

I’m rather tempted to stick an Iqool 12000 btu split on the landing to see me thru until then/ take the edge off.

[alabbasi]

The free standing units with the duct are not the most efficient. A window unit which can be temporary mounted or permanent mounted or a mini split would be the way to go if you're trying to cool a single room, Mini Splits are less obvious from inside the house and window units are less obvious outside the house.

[Simpo Two]

Danns said:

I’m somewhat sure you want to be putting both a supply and return duct to each room, to overcome the issues mentioned above - can get a 5 x 150mm plenum to go on the Daikin indoor unit.

The thing is that the lounge is open to the hall which is open to the landing. So if I'm pushing cold air into the lounge, surely the warm air wouldt be displaced upwards and, if necessary, I can make a hole in the landing ceiling back to the loft. I can't see why it wouldn't work, but it's an expensive and destructive mistake if it doesn't...

alabbasi said:

A window unit which can be temporary mounted or permanent mounted or a mini split would be the way to go if you're trying to cool a single room, Mini Splits are less obvious from inside the house and window units are less obvious outside the house.

Do you have any links please?

[SAS Tom]

Portable units might not be the most efficient but my view is that they do work. We bought one at work for a portakabin that is in the sun from sunrise to sunset. It would get to over 40 degrees inside and a 12000btu unit would cool it down.

I was looking for one for the house which every room has a south facing window and settled on a 9000btu unit last week. My thoughts were that it would be better to get 2x 9000 units rather than 1x12000 and now I’ve tested one I will be ordering a second.

I don’t find the noise a problem at all.

I believe the proper systems will be better but there is certainly a place for portable units.

[Dr Mike Oxgreen]

mrpbailey said:

Really?? 80% of the benefit of air con by blowing warm air around?!

Yes.

Because the air is moving, it certainly doesn’t feel warm. It definitely cools you down. We feel absolutely no need for aircon, even on a hot night.

[alabbasi]

Simpo Two said:

Do you have any links please?

For the UK, I can only find the mini split unit which is here: https://www.ebay.co.uk/itm/186309485983

That's actually a killer deal for a Mitsubishi unit but I'm not sure what the BTU's are and that's important to determine, depending on the size of the room you want to cool (12000BTU will cool up to a 500SQ/FT room).

This is a Window unit:

https://www.ebay.com/itm/326132289900

It basically fits in a window with it's rear hanging out or you can make a hole in the wall and install it that way which is how i have at my hobby shop office. They're more efficient when compared to the stand alone units that have an exhaust hose. They don't seem to be popular in the UK as I don't see any for sale.
.

Edited by alabbasi on Sunday 19th May 07:05

[NoTreadLeft]

Dr Mike Oxgreen said:

For a bedroom, I wouldn’t recommend air conditioning of any kind. Too noisy.

This.

Most of my wife’s family live in SE Asia where it’s generally a lot hotter & more humid than the British summer. Most rooms there have both aircon & ceiling fans but aircon almost never gets used: ceiling fans & windows open are the norm.

We now have a ceiling fan in our bedroom - it’s almost inaudible and keeps us plenty cool enough, even on it’s lowest setting. There’s no way I’d consider aircon.

[Danns]

SAS Tom said:

Portable units might not be the most efficient but my view is that they do work. We bought one at work for a portakabin that is in the sun from sunrise to sunset. It would get to over 40 degrees inside and a 12000btu unit would cool it down.

I was looking for one for the house which every room has a south facing window and settled on a 9000btu unit last week. My thoughts were that it would be better to get 2x 9000 units rather than 1x12000 and now I’ve tested one I will be ordering a second.

I don’t find the noise a problem at all.

I believe the proper systems will be better but there is certainly a place for portable units.

After looking for a while at the portables the following are the conclusions I came to;

The exhaust needs to be insulated to avoid heating the room
They really need to be converted to a twin pipe system (exactly zero twin pipes are available in the U.K) to work properly
They heavy
They noisy
They are about the same cost once you fix the above as getting a mini split (R290 or R32)
With the above mods it would take up a considerable amount of space

With that in mind, they dont look that attractive as an option!

Naturally I have no experience using one, all just from research.

[gangzoom]

NoTreadLeft said:

This.

Most of my wife’s family live in SE Asia where it’s generally a lot hotter & more humid than the British summer. Most rooms there have both aircon & ceiling fans but aircon almost never gets used: ceiling fans & windows open are the norm.

We now have a ceiling fan in our bedroom - it’s almost inaudible and keeps us plenty cool enough, even on it’s lowest setting. There’s no way I’d consider aircon.

Most of my extended families live in SE Asia, I CANNOT think of anyone who doesn't have/live by air con 24/7. I cannot wait to have the AC guys come and do the install for the two dormer bedrooms for the house renovation we are doing in the UK, with global warming here, there is no way I would consider NOT getting aircon in bedrooms.

Although I admit, in some areas, its pretty much impossible to have the infrastructure in place to have AC .

[NoTreadLeft]

mrpbailey said:

Really?? 80% of the benefit of air con by blowing warm air around?!

Ambient air temperature on a very warm UK night = 24C
Air temperature in an air conditioned room = 19C-ish
Temperature of your body = 37C

So plenty of scope for ambient air to cool you down, even on the warmest summer nights. You just need more of it, which is where a fan comes in.

[g40steve]

bogie said:

We upgraded from some portable units to Mitsubishi splt units a couple of years ago and the difference is fantastic. They take minutes to cool the room down (or warm it up) and are vastly more efficient when down to temp. We have a single unit outdoors serving 2 rooms above/below in one part of the house and another separate unit at other end of the house.

If you are in Lincs or East Midlands, Sth yorks then I can recommend https://www.josa-ac.co.uk/ very reasonable and professional install. They do ducted systems as well (through roofspace) if you dont want the indoor units on show.

Another vote for Josa ac will be getting a couple more soon.
The boss didn’t want shiny plastic cases on the wall so had to pay more for ours, in our S & W sunroom.