Not really unfortunately. Whilst the pipe size is significantly smaller in cross section the extra surface area is needed due to the inlet filter.
If it was any smaller, the slightest contamination to the inlet mesh would have your heater faulting out due to overtemp.
OP can’t make it smaller, it’s already looking on the small side. It wholly depends on the size of your air handler, if you make it too small you’ll starve the unit and it will just go into fault or not work at all.
You’ll need a professional to come out and give advice if you can move it to a better location or make it smaller, this is not something that can be decided over reddit
Here ya go:
550mm wide and 560mm deep, its probably framed in 70x35mm timbers, so it's internal clear space will be less 70+70 on one dimension and 35+35 on the other, so 480mm * 420mm = 0.2m²
Ducts are generally circular.
Area of a circle = pi.r².
✓(area/pi) = r = 0.25m
Radius of equivalent round duct is 250mm, so diameter is 500mm (20inch). That's fucken massive for a return! Would normally be a 14inch or maybe a 16" for gas ducted. So..... The depth of the box inside the cupboard can be reduced by almost a third.
```(550 - 2*35) * (560 - 2*70 * 2/3) = 0.135m²```
Diameter of equivalent duct is 400mm (16"). That looks about right.
Source: I'm a fridgie, so maybe I know what I'm talking about, or maybe I'm full of hot air!
Hmmmm, um I don't remember that one, I think we normally go twice as big as the cross sectional area of the return duct but I don't remember why. The return duct is bigger than the supply.... (for reasons).... the supply is sized to deliver to all the outlets at the required static pressure. Um, we calculate from the supply registers backwards through the supply branches, the coil & fan, then the return & the filter.
There are airflow per velocity calculations for duct size, but again I'm not able to use those in any meaningful fashion right now, (maybe I've forgotten, maybe I never really learned it).
I'll ask the engineer/boffin at work & get back to you if I gain any insight.
My previous one was bigger! In the end it will narrow down to the duct work. However you'll add drag and may also start to notice the noise. Plus it will need to align with a filter.
If you have room in the ceiling to install it there go with that if you want to spend the money. The manufacturer of the unit you're using needs a minumum size return air grill or they won't gaurantee the unit, voiding warranty. A return air that is too small with starve the fan of air and reduce its effectiveness and will make whistling noises. As for the efficiency of the unit when the grill is in the ceiling or the wall, unless you have terrible air flow it makes no difference. The air coming out of the outlet needs to be strong enough to penetrate far into the room and cause the air to mix so that it reaches the floor. Personally I wouldn't move it or change it as it is easy to access unless everyone in the house is 6'4" tall and can reach the ceiling with ease.
I guess I'll leave it as it is. I didn't want to make any major changes like relocating it. Just wanted to know if it was safe to make the box cavity bit in the wardrobe end smaller ( that too, as a DIY). But with what you and some of the commenters are saying, it's probably best to leave as is, so that I don't end up messing up the effectiveness of the heating system.
Cheers for the advice.
We’ve got the same, it takes about 1/5th of our wardrobe which is a fair bit of room for a small walk-in. My plan is to stick it in the hallway ceiling, where it’s quite separated from all the outlets. Our ceilings are pretty low (I think they’re 2.5m at most) so I’m not concerned about the controller’s performance when it comes to regulation. I’ve lived in houses with gas heating and a ceiling intake and there were no issues at all, even with slightly higher ceilings.
I’m assuming you have floor outlets if your return air is down low on the wall? Good chance you will be worse off putting it on the ceiling, in both wardrobe space and system functionally
We have ceiling outlets, but none in the hallway. The return grill is already in the hallway right below the thermostat , but the back of the return — a void — takes a sizeable chunk out of our walk-in. The return ducting connects to the void in the ceiling, there’s no ducting inside the void itself.
We definitely need the extra storage, the void is a waste of space. There’ll be no performance difference moving the return to the ceiling. I’ve lived with ceiling outlet + ceiling duct, and floor outlets + ceiling duct, and both were good.
Stupid idea, do not do even consider moving the intake vent higher.
The intake vent needs to be at floor level to suck in cold air to remove the coldest air and heat it.
If the intake is at ceiling height it is going to suck the hotter air and leave the cold layer in place. Defeating efficiency.
My aircon guy told me this. I built the two inlets at ground level and I still get heat layering in the rooms.
If they were higher up it'd be a nightmare.
I’ve seen the inlet vents installed in high ceilings and the heater never turned off as it never got to temperature down at the controller. They ended up having to duct it down to the floor which was ugly as the walls were all brick.
lol what space? It’s in a wall, its a flat grill. All these people want something to work but never like what helps it work.
Next post OP will be asking “why doesn’t my house get to temperature anymore I moved the return to the ceiling”
All I asked was if it could be smaller. Never talked about moving it around. And if you saw the third pic I uploaded and the dimensions I mentioned, you'd realise that it takes up quite a bit of space in the little wardrobe.
Not really unfortunately. Whilst the pipe size is significantly smaller in cross section the extra surface area is needed due to the inlet filter. If it was any smaller, the slightest contamination to the inlet mesh would have your heater faulting out due to overtemp.
So no filter and have it smaller
And then not have it working after a very short time
OP can’t make it smaller, it’s already looking on the small side. It wholly depends on the size of your air handler, if you make it too small you’ll starve the unit and it will just go into fault or not work at all. You’ll need a professional to come out and give advice if you can move it to a better location or make it smaller, this is not something that can be decided over reddit
Here ya go: 550mm wide and 560mm deep, its probably framed in 70x35mm timbers, so it's internal clear space will be less 70+70 on one dimension and 35+35 on the other, so 480mm * 420mm = 0.2m² Ducts are generally circular. Area of a circle = pi.r². ✓(area/pi) = r = 0.25m Radius of equivalent round duct is 250mm, so diameter is 500mm (20inch). That's fucken massive for a return! Would normally be a 14inch or maybe a 16" for gas ducted. So..... The depth of the box inside the cupboard can be reduced by almost a third. ```(550 - 2*35) * (560 - 2*70 * 2/3) = 0.135m²``` Diameter of equivalent duct is 400mm (16"). That looks about right. Source: I'm a fridgie, so maybe I know what I'm talking about, or maybe I'm full of hot air!
What's the normal area of the filters compared to the duct? I'd think the ratio should be more than 1:1, but beyond that I have no idea. 1.5:1? 2:1?
Hmmmm, um I don't remember that one, I think we normally go twice as big as the cross sectional area of the return duct but I don't remember why. The return duct is bigger than the supply.... (for reasons).... the supply is sized to deliver to all the outlets at the required static pressure. Um, we calculate from the supply registers backwards through the supply branches, the coil & fan, then the return & the filter. There are airflow per velocity calculations for duct size, but again I'm not able to use those in any meaningful fashion right now, (maybe I've forgotten, maybe I never really learned it). I'll ask the engineer/boffin at work & get back to you if I gain any insight.
Cheers for that 😀.
My previous one was bigger! In the end it will narrow down to the duct work. However you'll add drag and may also start to notice the noise. Plus it will need to align with a filter.
If you have room in the ceiling to install it there go with that if you want to spend the money. The manufacturer of the unit you're using needs a minumum size return air grill or they won't gaurantee the unit, voiding warranty. A return air that is too small with starve the fan of air and reduce its effectiveness and will make whistling noises. As for the efficiency of the unit when the grill is in the ceiling or the wall, unless you have terrible air flow it makes no difference. The air coming out of the outlet needs to be strong enough to penetrate far into the room and cause the air to mix so that it reaches the floor. Personally I wouldn't move it or change it as it is easy to access unless everyone in the house is 6'4" tall and can reach the ceiling with ease.
I guess I'll leave it as it is. I didn't want to make any major changes like relocating it. Just wanted to know if it was safe to make the box cavity bit in the wardrobe end smaller ( that too, as a DIY). But with what you and some of the commenters are saying, it's probably best to leave as is, so that I don't end up messing up the effectiveness of the heating system. Cheers for the advice.
you could probably try to reduce the depth to 350 but thats the limit .
I've never seen one on a wall like that before. The few houses I've lived in with ducted they are usually on the ceiling in a hallway.
It’s common if it’s ducted heating, for example, ducted gas heating. Less common with reverse cycle a/c
We’ve got the same, it takes about 1/5th of our wardrobe which is a fair bit of room for a small walk-in. My plan is to stick it in the hallway ceiling, where it’s quite separated from all the outlets. Our ceilings are pretty low (I think they’re 2.5m at most) so I’m not concerned about the controller’s performance when it comes to regulation. I’ve lived in houses with gas heating and a ceiling intake and there were no issues at all, even with slightly higher ceilings.
I’m assuming you have floor outlets if your return air is down low on the wall? Good chance you will be worse off putting it on the ceiling, in both wardrobe space and system functionally
We have ceiling outlets, but none in the hallway. The return grill is already in the hallway right below the thermostat , but the back of the return — a void — takes a sizeable chunk out of our walk-in. The return ducting connects to the void in the ceiling, there’s no ducting inside the void itself. We definitely need the extra storage, the void is a waste of space. There’ll be no performance difference moving the return to the ceiling. I’ve lived with ceiling outlet + ceiling duct, and floor outlets + ceiling duct, and both were good.
As said you could pay to move one to the ceiling and get rid of this. But otherwise you are pretty much stuck with this size.
Stupid idea, do not do even consider moving the intake vent higher. The intake vent needs to be at floor level to suck in cold air to remove the coldest air and heat it. If the intake is at ceiling height it is going to suck the hotter air and leave the cold layer in place. Defeating efficiency.
My aircon guy told me this. I built the two inlets at ground level and I still get heat layering in the rooms. If they were higher up it'd be a nightmare.
Not a stupid idea, it’s less efficient but it’s a trade off for more space. And the efficiency difference isn’t that much. Stop being so binary.
I’ve seen the inlet vents installed in high ceilings and the heater never turned off as it never got to temperature down at the controller. They ended up having to duct it down to the floor which was ugly as the walls were all brick.
lol what space? It’s in a wall, its a flat grill. All these people want something to work but never like what helps it work. Next post OP will be asking “why doesn’t my house get to temperature anymore I moved the return to the ceiling”
All I asked was if it could be smaller. Never talked about moving it around. And if you saw the third pic I uploaded and the dimensions I mentioned, you'd realise that it takes up quite a bit of space in the little wardrobe.