Discussion
Audis5b9 said:
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.
Simpo Two said:
dickymint said:
The company never answered my questions and has ignored subsequent e-mails. I phoned them this morning and they said they'd call me back. Hmm. Next week I might just turn up in reception.Also, may not help but Costco have a deal on Daikin A/C currently
https://www.costco.co.uk/Appliances/Cooling-Air-Tr...
https://www.costco.co.uk/Appliances/Cooling-Air-Tr...
heisthegaffer said:
Also, may not help but Costco have a deal on Daikin A/C currently
https://www.costco.co.uk/Appliances/Cooling-Air-Tr...
I make that over £1k for installation, nice work if you can get it! https://www.costco.co.uk/Appliances/Cooling-Air-Tr...
dickymint said:
What's the problem with having an extract duct to outside? Is this all about cost and if so what is your budget? I find it hard to believe that you can't find a domestic installer to price and fit a system that will work.
Only that I'd need 2x 6" ducts through my wardrobe rather than one; it's a physical issue not £. But the air can return up the stairs anyway. But because the local installers haven't done something like that before they either say 'sorry no' or worse, hide.heisthegaffer said:
Roughly where in East Anglia are you? How far from Herts?
About 50 miles. Somebody in mind?Regarding the kit, the internet is full of a/c kit to buy, but the installers - at the least the ones I've spoken to - only want to fit their own favourite make 'because it's the best/because we know it'. Is it possible to say 'I like THIS kit, just check the spec is OK then fit it for me?
Anyway, in a last desperate trawl of the net, I came across this link which leads to some new installers. So I'll call them tomorrow and hopefully get a fresh start. https://les.mitsubishielectric.co.uk/products/air-...
Ducted systems are difficult to retrofit into a building not designed for them, for obvious reasons. There’s nowhere to run the ductwork.
Upstairs is fairly easy though as you put FCU in the loft above the landing and then run the ductwork work to each respective room through the loft space. Return air path usually in the ceiling landing, and cut 10mm off the bottoms of all the doors to allow air back out of the rooms.
Downstairs is obviously more difficult as not only is there nowhere to run ducts, but it also needs to be on a separate zone. Either through a zone controller with powered duct dampers or a separate FCU for downstairs.
So for downstairs, wall mounted units is usually the easiest, or you need to create a risers from the loft down to the ceiling of downstairs to house the ductwork. Not insurmountable, but some building work needed. If I were doing it, I’d run ducts vertically down in wardrobes, closets, or the corners of rooms and box them in to hide them. Although you may run into fire reg issues doing that running ducts up into the loft from downstairs. Again not insurmountable, but would likely need decent fire stopping, as well as fire dampers for each vertical duct run.
If you have a cellar, or a decent crawl space though it’s easy. Just the opposite of what you did in the loft and have the air outlets in the floor instead which is common practice.
Upstairs is fairly easy though as you put FCU in the loft above the landing and then run the ductwork work to each respective room through the loft space. Return air path usually in the ceiling landing, and cut 10mm off the bottoms of all the doors to allow air back out of the rooms.
Downstairs is obviously more difficult as not only is there nowhere to run ducts, but it also needs to be on a separate zone. Either through a zone controller with powered duct dampers or a separate FCU for downstairs.
So for downstairs, wall mounted units is usually the easiest, or you need to create a risers from the loft down to the ceiling of downstairs to house the ductwork. Not insurmountable, but some building work needed. If I were doing it, I’d run ducts vertically down in wardrobes, closets, or the corners of rooms and box them in to hide them. Although you may run into fire reg issues doing that running ducts up into the loft from downstairs. Again not insurmountable, but would likely need decent fire stopping, as well as fire dampers for each vertical duct run.
If you have a cellar, or a decent crawl space though it’s easy. Just the opposite of what you did in the loft and have the air outlets in the floor instead which is common practice.
dvs_dave said:
Downstairs is obviously more difficult as not only is there nowhere to run ducts, but it also needs to be on a separate zone. Either through a zone controller with powered duct dampers or a separate FCU for downstairs.
So for downstairs, wall mounted units is usually the easiest, or you need to create a risers from the loft down to the ceiling of downstairs to house the ductwork. Not insurmountable, but some building work needed. If I were doing it, I’d run ducts vertically down in wardrobes, closets, or the corners of rooms and box them in to hide them. Although you may run into fire reg issues doing that running ducts up into the loft from downstairs. Again not insurmountable, but would likely need decent fire stopping, as well as fire dampers for each vertical duct run.
As mentioned, from loft to downstairs ceiling would be a 6" duct through a wardrobe as you suggest (see my sketch). There's no door between the lounge, hall and landing so as the cooled air descends the unwanted hot air is displaced upwards. It has to be.So for downstairs, wall mounted units is usually the easiest, or you need to create a risers from the loft down to the ceiling of downstairs to house the ductwork. Not insurmountable, but some building work needed. If I were doing it, I’d run ducts vertically down in wardrobes, closets, or the corners of rooms and box them in to hide them. Although you may run into fire reg issues doing that running ducts up into the loft from downstairs. Again not insurmountable, but would likely need decent fire stopping, as well as fire dampers for each vertical duct run.
But I lose you when you talk of zones and powered dampers. Why can't I just switch it on and off as required, or have it operating on a thermostat?
Nobody's mentioned fire regs before, that's a new brick wall to climb over. But as the lounge is open to everything I can't think it makes any difference at all...
Simpo Two said:
As mentioned, from loft to downstairs ceiling would be a 6" duct through a wardrobe as you suggest (see my sketch). There's no door between the lounge, hall and landing so as the cooled air descends the unwanted hot air is displaced upwards. It has to be.
But I lose you when you talk of zones and powered dampers. Why can't I just switch it on and off as required, or have it operating on a thermostat?
Nobody's mentioned fire regs before, that's a new brick wall to climb over. But as the lounge is open to everything I can't think it makes any difference at all...
You either have 2 separate systems, one for upstairs and one for downstairs (although depending on cooling requirement may get away with 1 external unit), or you have 1 system with separate control of upstairs and downstairs (2 zones), which will need a valve/"door" arrangement to send the cool air to one zone only. But I lose you when you talk of zones and powered dampers. Why can't I just switch it on and off as required, or have it operating on a thermostat?
Nobody's mentioned fire regs before, that's a new brick wall to climb over. But as the lounge is open to everything I can't think it makes any difference at all...
Would be very unusual to have the whole house on one temperature , and it wouldn't work that well anyway as each room will have a different heat profile, but if you have 1 thermostat some areas will end up being hotter and some cooler. Also seems quite an expensive way to do it, you'd be cooling the bedrooms during the day and the living room at night.
Why wouldn't you want normal split systems in each room you wish to cool? Wayyyy more control, much more energy efficient as you're only cooling the rooms you want to, and no problems with some rooms being hotter than others when you have the AC on or off. The indoor boxes are not very intrusive.
Condi said:
Why wouldn't you want normal split systems in each room you wish to cool? Wayyyy more control, much more energy efficient as you're only cooling the rooms you want to, and no problems with some rooms being hotter than others when you have the AC on or off. The indoor boxes are not very intrusive.
I have a centralised system, each room has its own controller. The grilles are flush to the wall, they look and perform much better than a split system. No drafts or chill spots. Quite a contrast to our office where several people wear jumpers as they’re sat right in the path of the ac. A properly designed and well insulated ducted system is also more thermally efficient.
But mainly, aesthetics.
Simpo Two said:
As mentioned, from loft to downstairs ceiling would be a 6" duct through a wardrobe as you suggest (see my sketch). There's no door between the lounge, hall and landing so as the cooled air descends the unwanted hot air is displaced upwards. It has to be.
But I lose you when you talk of zones and powered dampers. Why can't I just switch it on and off as required, or have it operating on a thermostat?
Nobody's mentioned fire regs before, that's a new brick wall to climb over. But as the lounge is open to everything I can't think it makes any difference at all...
Just dumping the cold air in the middle of the house hoping it’ll displace the warm won’t work. Air doesn’t behave like water and just fill up a space from bottom to top. It primarily flows from high pressure to low pressure. So with your proposal, it’ll just be really cold near the air outlet and warm throughout the rest of the space. This is because the air follows the shortest path, so it’ll just circulate back up to the fan coil and leave everywhere else filled with unconditioned air.But I lose you when you talk of zones and powered dampers. Why can't I just switch it on and off as required, or have it operating on a thermostat?
Nobody's mentioned fire regs before, that's a new brick wall to climb over. But as the lounge is open to everything I can't think it makes any difference at all...
The cold air needs to be fed in around the perimeter of the conditioned space (also like heated air), with the return roughly in the center. This forces circulation of air throughout the entire space, in turn ensuring cool air throughout.
Have a look at any ducted HVAC system in an open plan office, and you’ll see that the majority of the air is fed into the space around the perimeter, and the return (usually hidden) is in the center. Any air supply diffusers not around the perimeter are just to ensure even temperature distribution and fresh air throughout the space.
The basics that apply to commercial system also apply to domestic.
You are seeking a bodge and hence no one will touch it.
I have a whole house ducted system. For ducted systems the installer takes house measurements etc and then sends the whole lot to the manufacturers quoting team. They then size the system, design it and send it back. I have had 2 whole house systems from 2 manufactures -lg and Samsung. Different suppliers same process
The installer then installs to that plan. It is very different from buying a few ac units off the shelf.
There will be some cowboys but the vendor wants a system that works as designed and cools the rooms correctly. If not people complain/ want their money back etc.
Ask a builder to bodge someting. Most won't do it but someone will.
Return air that is not from the room will just feed war air back into the system all the time and never allow the air to re cycle and get properly cold.
In 2 other houses we did bodge it with one unit serving 2 bedrooms with hall return air. It did work as the rooms were relatively small and we only ran it at night.
In another we tried the same between 2 larger rooms ( second was a spare room ) with unequal duct lengths. Didn't cool the second room at all.
Ducted fan units are cheap. Give or take £500 each. Each can have independent control and the return air will come from the room concerned.
In your case if one is a bedroom and one a living room then assumptions can be made that both rooms won't need full cooling at the same time which keeps down the size of the compressor feeding it all.
Ask for it to be done properly and people will quote. The installers do this for a living and know what works and what just causes hassle.
As with most industries jobs cut corner cheap jobs cause them problems.
I have a whole house ducted system. For ducted systems the installer takes house measurements etc and then sends the whole lot to the manufacturers quoting team. They then size the system, design it and send it back. I have had 2 whole house systems from 2 manufactures -lg and Samsung. Different suppliers same process
The installer then installs to that plan. It is very different from buying a few ac units off the shelf.
There will be some cowboys but the vendor wants a system that works as designed and cools the rooms correctly. If not people complain/ want their money back etc.
Ask a builder to bodge someting. Most won't do it but someone will.
Return air that is not from the room will just feed war air back into the system all the time and never allow the air to re cycle and get properly cold.
In 2 other houses we did bodge it with one unit serving 2 bedrooms with hall return air. It did work as the rooms were relatively small and we only ran it at night.
In another we tried the same between 2 larger rooms ( second was a spare room ) with unequal duct lengths. Didn't cool the second room at all.
Ducted fan units are cheap. Give or take £500 each. Each can have independent control and the return air will come from the room concerned.
In your case if one is a bedroom and one a living room then assumptions can be made that both rooms won't need full cooling at the same time which keeps down the size of the compressor feeding it all.
Ask for it to be done properly and people will quote. The installers do this for a living and know what works and what just causes hassle.
As with most industries jobs cut corner cheap jobs cause them problems.
heisthegaffer said:
Roughly where in East Anglia are you? How far from Herts?
About 50 miles. Somebody in mind?https://inspace.co.uk/
dvs_dave said:
Just dumping the cold air in the middle of the house hoping it’ll displace the warm won’t work. Air doesn’t behave like water and just fill up a space from bottom to top. It primarily flows from high pressure to low pressure. So with your proposal, it’ll just be really cold near the air outlet and warm throughout the rest of the space. This is because the air follows the shortest path, so it’ll just circulate back up to the fan coil and leave everywhere else filled with unconditioned air.
Interesting, OK.dvs_dave said:
The cold air needs to be fed in around the perimeter of the conditioned space (also like heated air), with the return roughly in the center. This forces circulation of air throughout the entire space, in turn ensuring cool air throughout.
Unless it's been built into the house, no domestic system will do that - they all blow cold air out of one vent somewhere...Jeremy-75qq8 said:
You are seeking a bodge and hence no one will touch it.
Well, to start with I ask them to specify and quote for ducted a/c. They look at my simpl 3-bed house and shake their head and say it can't be done. Except one, who rushed off a quick quote before going on holiday with much detail missing then stopped answering e-mails.Jeremy-75qq8 said:
I have a whole house ducted system. For ducted systems the installer takes house measurements etc and then sends the whole lot to the manufacturers quoting team. They then size the system, design it and send it back. I have had 2 whole house systems from 2 manufactures -lg and Samsung. Different suppliers same process
The installer then installs to that plan. It is very different from buying a few ac units off the shelf.
I would love to get a quote from a proper a/c company for ducted a/c. That's where I started the journey, but I can't find any in the area.The installer then installs to that plan. It is very different from buying a few ac units off the shelf.
Jeremy-75qq8 said:
Ducted fan units are cheap. Give or take £500 each. Each can have independent control and the return air will come from the room concerned.
In your case if one is a bedroom and one a living room then assumptions can be made that both rooms won't need full cooling at the same time which keeps down the size of the compressor feeding it all.
Of course. It makes no sense to cool an empty bedroom all day. Logically I would turn off the lounge a/c in the early evening and turn the bedroom one on. Re £500, the installers shake their heads and say ducted systems are very expensive.In your case if one is a bedroom and one a living room then assumptions can be made that both rooms won't need full cooling at the same time which keeps down the size of the compressor feeding it all.
Jeremy-75qq8 said:
Ask for it to be done properly and people will quote. The installers do this for a living and know what works and what just causes hassle.
The usual route is 'No we can't because we'd have to get a duct from the loft to downstairs'. I tell them that there's a direct vertical route through a built-in wardrobe, and take them upstairs and say 'Look, here is where a 6" duct would run. But they're not interested.Edited by Simpo Two on Monday 20th May 09:43
heisthegaffer said:
Have sent them a message, thanks!dvs_dave said:
Just dumping the cold air in the middle of the house hoping it’ll displace the warm won’t work. Air doesn’t behave like water and just fill up a space from bottom to top. It primarily flows from high pressure to low pressure. So with your proposal, it’ll just be really cold near the air outlet and warm throughout the rest of the space. This is because the air follows the shortest path, so it’ll just circulate back up to the fan coil and leave everywhere else filled with unconditioned air.
Genuine question. Up until now I assumed the return duct was next to the exit duct. But maybe it isn't. Where would you normally have a return duct? In the region of lowest pressure? If so where is it likely to be?Do you think installers are also worried about the fact the lounge has an archway to the hall stairs and landing - so can't be closed off?
It is the air handling unit and that is £500. This excludes install and ducting. The until needs to be connected to the cooling circuit using high pressure insulated pipework.
The point I am making is that to do it properly with a ducted unit for the bedroom and living room will not add significantly to the incremental cost
Re " just piping the air downstairs " it is not that simple.
They will need ( to do it properly ) so calculate based n the length of the duct and curves and then compare it to the maximum allowed back pressure of the air handler which this likely exceeds.
As above ask them to quote for the 2 rooms done properly and they will quote.
Return air is in the same room as the outlet but sufficiently far away to ensure it cannot just recirculate.
Ours was a new build and we still faced limitations. It is preferable to have the ducts over windows ( particularly if south facing ) but building limitations of the service depth in the ceiling coupled with other stuff ( plumbing / waste / vent / electrics etc ) still lead to limitations that are difficult to overcome.
We have units building into tv joinery that suck from below and expel at the top so so can with effort make things vanish.
Ducted air will always be more expensive. It is invasive to fit ( even in a new build ) and it is is only made by a few mainline manufacturers unlike the wall mounted units that are churned out by many manufacturers.
I would look at a multi split with 2 wall mount units and hide them in joinery / top of wardrobe etc.
It will cost you less and work well.
The point I am making is that to do it properly with a ducted unit for the bedroom and living room will not add significantly to the incremental cost
Re " just piping the air downstairs " it is not that simple.
They will need ( to do it properly ) so calculate based n the length of the duct and curves and then compare it to the maximum allowed back pressure of the air handler which this likely exceeds.
As above ask them to quote for the 2 rooms done properly and they will quote.
Return air is in the same room as the outlet but sufficiently far away to ensure it cannot just recirculate.
Ours was a new build and we still faced limitations. It is preferable to have the ducts over windows ( particularly if south facing ) but building limitations of the service depth in the ceiling coupled with other stuff ( plumbing / waste / vent / electrics etc ) still lead to limitations that are difficult to overcome.
We have units building into tv joinery that suck from below and expel at the top so so can with effort make things vanish.
Ducted air will always be more expensive. It is invasive to fit ( even in a new build ) and it is is only made by a few mainline manufacturers unlike the wall mounted units that are churned out by many manufacturers.
I would look at a multi split with 2 wall mount units and hide them in joinery / top of wardrobe etc.
It will cost you less and work well.
Edited by Jeremy-75qq8 on Monday 20th May 11:06
Jeremy-75qq8 said:
It is the air handling unit and that is £500. This excludes install and ducting. The until needs to be connected to the cooling circuit using high pressure insulated pipework.
The point I am making is that to do it properly with a ducted unit for the bedroom and living room will not add significantly to the incremental cost
Re " just piping the air downstairs " it is not that simple.
They will need ( to do it properly ) so calculate based n the length of the duct and curves and then compare it to the maximum allowed back pressure of the air handler which this likely exceeds.
As above ask them to quote for the 2 rooms done properly and they will quote.
Return air is in the same room as the outlet but sufficiently far away to ensure it cannot just recirculate.
Ours was a new build and we still faced limitations. It is preferable to have the ducts over windows ( particularly if south facing ) but building limitations of the service depth in the ceiling coupled with other stuff ( plumbing / waste / vent / electrics etc ) still lead to limitations that are difficult to overcome.
We have units building into tv joinery that suck from below and expel at the top so so can with effort make things vanish.
Ducted air will always be more expensive. It is invasive to fit ( even in a new build ) and it is is only made by a few mainline manufacturers unlike the wall mounted units that are churned out by many manufacturers.
I would look at a multi split with 2 wall mount units and hide them in joinery / top of wardrobe etc.
It will cost you less and work well.
Good post, thanks. I am resigned to have split a/c if necessary - if the lounge could have a ceiling mounted unit it would fit in better.The point I am making is that to do it properly with a ducted unit for the bedroom and living room will not add significantly to the incremental cost
Re " just piping the air downstairs " it is not that simple.
They will need ( to do it properly ) so calculate based n the length of the duct and curves and then compare it to the maximum allowed back pressure of the air handler which this likely exceeds.
As above ask them to quote for the 2 rooms done properly and they will quote.
Return air is in the same room as the outlet but sufficiently far away to ensure it cannot just recirculate.
Ours was a new build and we still faced limitations. It is preferable to have the ducts over windows ( particularly if south facing ) but building limitations of the service depth in the ceiling coupled with other stuff ( plumbing / waste / vent / electrics etc ) still lead to limitations that are difficult to overcome.
We have units building into tv joinery that suck from below and expel at the top so so can with effort make things vanish.
Ducted air will always be more expensive. It is invasive to fit ( even in a new build ) and it is is only made by a few mainline manufacturers unlike the wall mounted units that are churned out by many manufacturers.
I would look at a multi split with 2 wall mount units and hide them in joinery / top of wardrobe etc.
It will cost you less and work well.
FWIW here's the quote I got last October:
installer said:
Bedroom and Lounge
The above areas would operate from one outdoor heat pump AC condenser. This would be wall
mounted on Brackets.
The indoor FCU would be a ducted unit in the loft mounted to the joists with the final position to
be agreed on site. Interconnecting services would run across the loft and down the external wall
to the condensing unit.
Condensate running to ground level or suitable drain guttering.
Supply Air ducting would run from the FCU down through the Studio to the Lounge and directly
from the loft into the main bedroom. Return air would be pulled from the landing. Both Supply
and Return air will enter and return from Circular white ceiling vents.
Temperature can be controlled in various ways to suit once installation is complete.
1. 50/50 control between the control and air return sensor.
2. 100% air Return Sensor
3. 100% controller Sensor
To install Daikin air conditioning equipment as detailed below including:
? 1 x Daikin RXM50R Condenser
? 1 x Daikin FDXM50F9
? 1 x Installation and services
? Pressure Test
? Commissioning
Price
For the sum of £3,296.00 + VAT
(Three Thousand, Two Hundred & Ninety-Six Pounds)
240v Mains Electrical supply required to the outdoor unit will be
Fuse rating 20amp
Run current 3amps approx.
Terms & Conditions
1. The terms of payment are – 30 days from application.
2. These prices are valid for 30 days from the quotation date unless agreed otherwise in
writing.
3. VAT is excluded from our prices and will be added at the time of invoicing at the national
rate.
4.
Exclusions
? Work outside normal working hours
? Power Supply Wiring
? Building trade work, making good or redecoration
? Special vehicles, timed, weekend or out of hours’ delivery
The above areas would operate from one outdoor heat pump AC condenser. This would be wall
mounted on Brackets.
The indoor FCU would be a ducted unit in the loft mounted to the joists with the final position to
be agreed on site. Interconnecting services would run across the loft and down the external wall
to the condensing unit.
Condensate running to ground level or suitable drain guttering.
Supply Air ducting would run from the FCU down through the Studio to the Lounge and directly
from the loft into the main bedroom. Return air would be pulled from the landing. Both Supply
and Return air will enter and return from Circular white ceiling vents.
Temperature can be controlled in various ways to suit once installation is complete.
1. 50/50 control between the control and air return sensor.
2. 100% air Return Sensor
3. 100% controller Sensor
To install Daikin air conditioning equipment as detailed below including:
? 1 x Daikin RXM50R Condenser
? 1 x Daikin FDXM50F9
? 1 x Installation and services
? Pressure Test
? Commissioning
Price
For the sum of £3,296.00 + VAT
(Three Thousand, Two Hundred & Ninety-Six Pounds)
240v Mains Electrical supply required to the outdoor unit will be
Fuse rating 20amp
Run current 3amps approx.
Terms & Conditions
1. The terms of payment are – 30 days from application.
2. These prices are valid for 30 days from the quotation date unless agreed otherwise in
writing.
3. VAT is excluded from our prices and will be added at the time of invoicing at the national
rate.
4.
Exclusions
? Work outside normal working hours
? Power Supply Wiring
? Building trade work, making good or redecoration
? Special vehicles, timed, weekend or out of hours’ delivery
I said:
Thanks very much for the quote; I'd like to progress to a fully detailed and costed proposal.
I need to envisage and understand the entire system before proceeding, so I'd be grateful if you could supply details on:
1) External unit/condenser
2) Controller/timer
3) Ducting - photos?
4) Anything else
The proposed Daikin FCU is 2019 - is that still the most suitable?
I've looked again at where the ducts will come out and I think the best exit downstairs will be if they go through the middle of the built-in wardrobe (I'm good at DIY so will adjust the shelving as required). This should bring the ducting out just behind the cold water tank in the roof.
Look forward to hearing from you.
.I need to envisage and understand the entire system before proceeding, so I'd be grateful if you could supply details on:
1) External unit/condenser
2) Controller/timer
3) Ducting - photos?
4) Anything else
The proposed Daikin FCU is 2019 - is that still the most suitable?
I've looked again at where the ducts will come out and I think the best exit downstairs will be if they go through the middle of the built-in wardrobe (I'm good at DIY so will adjust the shelving as required). This should bring the ducting out just behind the cold water tank in the roof.
Look forward to hearing from you.
And that was it. The quote was valid for 30 days but I never heard back from them so it was all wasted.
(NB Why did they add VAT to the total?)
Simpo Two said:
dvs_dave said:
Just dumping the cold air in the middle of the house hoping it’ll displace the warm won’t work. Air doesn’t behave like water and just fill up a space from bottom to top. It primarily flows from high pressure to low pressure. So with your proposal, it’ll just be really cold near the air outlet and warm throughout the rest of the space. This is because the air follows the shortest path, so it’ll just circulate back up to the fan coil and leave everywhere else filled with unconditioned air.
Genuine question. Up until now I assumed the return duct was next to the exit duct. But maybe it isn't. Where would you normally have a return duct? In the region of lowest pressure? If so where is it likely to be?Do you think installers are also worried about the fact the lounge has an archway to the hall stairs and landing - so can't be closed off?
Ductless systems get around the single point of supply and return by having relatively high velocity air supply and wide angle active air distribution louvers to distribute the air throughout the space to stop it short circuiting right back into the return.
Ducted systems don't have the air velocity or active air distribution louvers for them to work effectively that way, hence why properly designed built-in ducted systems supply the air around the perimeter, with the return air plenum roughly being the in the center of the house, either via a specific return air duct riser, and/or via the stairwell.
I think in your case the best option and guarantee of performance is going to be a ducted FCU unit for the upstairs, and recessed ceiling mounted cassette unit for the downstairs where you're proposing to have your supply air duct. Or a couple of wall consoles to ensure even air distribution throughout the downstairs space. And don't ask contractors for "air conditioning" as then they have to charge VAT. If you ask for an air-to-air heat pump system (which can also cool), then you can exclude VAT.
That's a great reply! I didn't know there was a difference in airflow between ducted and wall-mounted units, and finally explains why ducted won't work downstairs. Why don't FCUs doesn't have as much grunt as a wall-mounted unit?
I thought of a ceiling cassette downstairs but it would project into the room above. That could indeed be into the wardrobe, but the size of the unit would mean cutting one or possibly two joists. How do they get round that?
I thought of a ceiling cassette downstairs but it would project into the room above. That could indeed be into the wardrobe, but the size of the unit would mean cutting one or possibly two joists. How do they get round that?
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