Recommend ducted heat pump / HVAC air return options - door trim / transfer grills for bedrooms

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timmmay

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#281201 4-Feb-2021 20:50

Our Panasonic ducted system has gone in, and so far it works ok. Not really very impressed with the weekly timer, which can't change the fan speed or mode, which is ok if it's always hot or always cold but right now we air condition at night and heat in the morning. If they ever get the WiFi to work apparently it's a bit more flexible, but a really terrible app.

Because some of our bedroom doors are closed at night we will need a way to let the air out of the room, as these systems rely on push air out / pull it back / cycle it around. If you don't do it the pressure in the rooms can make it uncomfortable, it pushes air out through floorboards in the closed rooms, and the return area is low pressure so ceiling cavity / floor air can come in which isn't ideal.

I've been reading and there are five main options for letting air out of rooms with closed doors:

Trim the bottom of the doors so air can pass underneath. I've read that sometimes this works ok, but you have to cut at least 1cm and 2cm is recommended which would look weird and let light / sound into kids rooms. Currently when the door is closed the airflow out of the room is really tiny, I guess about 5 - 10% of the flow when the door is open. Interestingly, when the door is open more air moves through near the top than near the floor. This would force the air down, which is probably better for circulation, but really want to block light / sound because kids room near lounge. Wife says maybe ok.
Door grill. Wife says no, they're ugly. They would be quite effective. Our doors are plain white lightweight ones.
Wall grill. Wife says better than door grills, put it above the door. They can be thicker so might be able to have baffles to reduce sound / light. They would work better if they were near the floor in the corner opposite the outlet, so air is drawn down rather than just staying up at the ceiling, but I don't know much difference that makes. Something like this (USA).
Jump duct. Basically a standard ceiling duct inside the bedroom, another outside in the hallway, with a very short duct between them. Wife says no, ugly. Also means it goes into the roof space so loses heat in winter.
Dedicated return duct. Probably not an feasible option given it's all set up already, the company I used is more of a low price high volume type place I think. It would also involve more parts, diffusers, ducts, splitters, balancing, etc, I'd probably need another company to do it.
My wife prefers the option of a grill probably up high above the door, or if there's wood in the way then somewhere else up high. Our ceilings are pretty tall, 2.8m from memory, so you'd probably not notice them up high same as you don't notice the return grill.

I'm interested in experience from people who have knowledge or experience in this area about which option is best, and if it's a grill a product recommendation ideally with some kind of light / noise baffle.

Relevant articles: one, two, three.

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#2647658 4-Feb-2021 21:06

Any grill between rooms will also let sound/light/drafts through as well at various times. Dedicated return duct in each room is best option from technical POV, gives the option to run with doors open or closed. Obviously depends on your installation if this is feasible.

timmmay

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#2647664 4-Feb-2021 21:53

RunningMan:

Any grill between rooms will also let sound/light/drafts through as well at various times. Dedicated return duct in each room is best option from technical POV, gives the option to run with doors open or closed. Obviously depends on your installation if this is feasible.

Yeah technically probably better, but really unlikely to happen. Also means air goes in ceiling height, extracted ceiling height, I wonder if you end up in winter with the ceiling warm and the floor cool. We do have Holyoake ducts that send a fraction of the air straight down through holes.

sm250

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#2653270 10-Feb-2021 21:26

We are looking at this PRIOR to installation of a ducted heat pump. We've been quoted ~5k extra to put returns in each room.

Some salespeople I speak to are trying to put me off that idea and say it works just as well have a 10 mm gap at the bottom of the door. My wife is not very happy with that idea - basically for the same reasons you mentioned. She doesn't want light and sound going into or out of the kids rooms. Doesn't seem to be an easy solution! One salesperson said the returns would need to be cleaned every 3 to 6 months and we'd have to get into the ceiling to do it, so that sounds a bit unmanageable.

I'm looking at the door grill idea, but like you getting pushback on that. They seem to work pretty well, but I haven't yet gone too far down that path. Do you know how much sound/light would get through? And can you buy them in this country?

timmmay

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#2653277 10-Feb-2021 22:00

Have you read those articles linked above? I have another one which I saved as PDF on another computer which shoes the relative airflow of each of the options. 2cm is pretty good but noise and light issues, 1cm is ok, but it can discolor the carpet if it gets all dusty as it acts like a filter. Our doors are quite tight on the carpet and I want to keep it that way. Door grills are just ugly.

I think NZ's industry is quite immature and there's only basic products around. My current plan is to order some of these return air wall transfer grills 12 x 4 inch or 12 x 6 inch if I can figure out if they will fit the depth of our walls and between the studs, via youshop. They provide some noise / light suppression, not much I guess but better than nothing. I think I might put them low down in the opposite corner of the rooms as the outlets so air is drawn across and down the room. On the other hand, I wonder if up high they'd not be as noticeable or let as much noise / light in.

Holyoake which makes things in NZ has a light resistant grill but no box around it, think it's door not wall, so the air might pick up dust and stuff inside the walls.

Return ducts shouldn't be $5K. All you'd need is a diffuser, some ducting, and a splitter, which sounds like about $100 per room plus another maybe $100 for the splitter / junction - at a guess. If you wanted a jump duct (which is a diffuser on each side of the wall with a small piece of duct) that's about $100 per room, works ok, but means the heat comes out the ceiling, goes back in the ceiling, so I wonder if lower down the room will be effectively heated.

jjnz1

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#2653278 10-Feb-2021 22:01

Hey @timmmay

We have a Panasonic ducted with 7 outlets (3 beds, 1x office, 1x hall, 1x lounge, 1x kitchen) and it works fine (ish) when we close doors.

We notice that the room that's closed off from the return vent is a few degrees different but still works well
IE, lounge and kitchen closed off, system set at 20 degrees heating, lounge gets to around 22, bedrooms stay at around 20.
IE, if our office is closed off when system set at 20 degrees heating, office gets to 24, rest of house 20.
The bedrooms maybe only 1 degree difference when doors closed. (which is mostly at night).

This actually suits us well, and we haven't been disadvantaged.

EDIT- our door gaps under each door is ~1cm. Generally wooden floor to carpet in rooms.

sm250

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#2654274 10-Feb-2021 22:40

timmmay:

Have you read those articles linked above? I have another one which I saved as PDF on another computer which shoes the relative airflow of each of the options. 2cm is pretty good but noise and light issues, 1cm is ok, but it can discolor the carpet if it gets all dusty as it acts like a filter. Our doors are quite tight on the carpet and I want to keep it that way. Door grills are just ugly.

I think NZ's industry is quite immature and there's only basic products around. My current plan is to order some of these return air wall transfer grills 12 x 4 inch or 12 x 6 inch if I can figure out if they will fit the depth of our walls and between the studs, via youshop. They provide some noise / light suppression, not much I guess but better than nothing. I think I might put them low down in the opposite corner of the rooms as the outlets so air is drawn across and down the room. On the other hand, I wonder if up high they'd not be as noticeable or let as much noise / light in.

Holyoake which makes things in NZ has a light resistant grill but no box around it, think it's door not wall, so the air might pick up dust and stuff inside the walls.

Return ducts shouldn't be $5K. All you'd need is a diffuser, some ducting, and a splitter, which sounds like about $100 per room plus another maybe $100 for the splitter / junction - at a guess. If you wanted a jump duct (which is a diffuser on each side of the wall with a small piece of duct) that's about $100 per room, works ok, but means the heat comes out the ceiling, goes back in the ceiling, so I wonder if lower down the room will be effectively heated.

Just realised I said 10cm door gap, meant 10mm! (now changed in my post) Some of our doors are close to 1cm now but it will probably double the gap on most of them, so I would expect would let more sound and light in. But have to compromise somewhere. Based on some of the articles that you linked to, sounds like that would probably be just about enough.

Yup, the articles have been fascinating and very helpful in my thinking process, thanks!

Found some reviews on Amazon of the Perfect Balance Interior Door Air Transfer Grille. Sadly, some said: "What's worse, the vent lets in a lot more light and sound than they have you believe." Although others said it was fine so hard to tell!

I'm talking to the salesperson who quoted the extra $5k tomorrow night. We'd have 8 return ducts I think. Will be interesting to discuss. In my case what we were planning to do (not entirely sure this is what he quoted for) was to run returns from the bottom of the wall up through the wardrobe behind and into the ceiling. That way you get the floor-to-ceiling movement. But it's a lot of extra money and I don't think my wife is going to be happy to lose wardrobe space :-) So I'll have to confirm how he has quoted for that.

Thanks for the advice. Is really helpful.

timmmay

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#2654375 11-Feb-2021 05:56

jjnz1:

Hey @timmmay

We have a Panasonic ducted with 7 outlets (3 beds, 1x office, 1x hall, 1x lounge, 1x kitchen) and it works fine (ish) when we close doors.

We notice that the room that's closed off from the return vent is a few degrees different but still works well
IE, lounge and kitchen closed off, system set at 20 degrees heating, lounge gets to around 22, bedrooms stay at around 20.
IE, if our office is closed off when system set at 20 degrees heating, office gets to 24, rest of house 20.
The bedrooms maybe only 1 degree difference when doors closed. (which is mostly at night).

This actually suits us well, and we haven't been disadvantaged.

EDIT- our door gaps under each door is ~1cm. Generally wooden floor to carpet in rooms.

Thanks, interesting. 1cm is a decent gap, our doors touch the carpet. When I hold my hand near the door when it's closed I guess about 5% of the air that would normally flow comes around the edges of the door. Having a room set to 20 get to 24 would be a problem for us, I noticed that too, and because of that until I get some kind of return I'm not going to use the heating or cooling once my son goes to bed about 7pm. Fortunately we can get away with that for a month or so given the time of year.

I think wall returns are a good economical option, centered above the door they look fine but I think ours have wood in the way, hence will try going lower down.

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timmmay

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#2654376 11-Feb-2021 06:00

sm250:

Just realised I said 10cm door gap, meant 10mm! (now changed in my post) Some of our doors are close to 1cm now but it will probably double the gap on most of them, so I would expect would let more sound and light in. But have to compromise somewhere. Based on some of the articles that you linked to, sounds like that would probably be just about enough.

Yup, the articles have been fascinating and very helpful in my thinking process, thanks!

Found some reviews on Amazon of the Perfect Balance Interior Door Air Transfer Grille. Sadly, some said: "What's worse, the vent lets in a lot more light and sound than they have you believe." Although others said it was fine so hard to tell!

I'm talking to the salesperson who quoted the extra $5k tomorrow night. We'd have 8 return ducts I think. Will be interesting to discuss. In my case what we were planning to do (not entirely sure this is what he quoted for) was to run returns from the bottom of the wall up through the wardrobe behind and into the ceiling. That way you get the floor-to-ceiling movement. But it's a lot of extra money and I don't think my wife is going to be happy to lose wardrobe space :-) So I'll have to confirm how he has quoted for that.

Thanks for the advice. Is really helpful.

Good idea to look on Amazon for reviews. They're a bit disappointing really, they work but sloppy construction and the baffles only help a bit with noise.

$5K for returns when they have to run from the floor makes more sense, that's a bit of work. You could consider jump ducts up in the ceiling, and use diffuers that push most of the air down towards the floor. The holyoake diffusers seem to push I guess around 20% of the air straight down and the rest goes out the sides and is angled down a bit. I guess with jump ducts you could put diffusers in each room opposite side, have all the ducts combine using a splitter, but that could be a lot of air through one return diffuser which would be loud.

I don't think there's a perfect solution if you want quiet rooms and good air movement :( Paying for return air vents that are just standard diffusers in the ceiling might be worthwhile and should cost less than $5K, but less effective than returns near the floor.

Danite

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#2654459 11-Feb-2021 09:57

I have had a ducted system installed for about a year now and had vague concerns about this. My solution if I ever get round to it as I will do it myself is to cut the cupboard doors shorter mabye the 20mm suggested or 10mm for a double and then put the return vent in the roof of the cupboard..

timmmay

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#2654468 11-Feb-2021 10:10

Danite:

I have had a ducted system installed for about a year now and had vague concerns about this. My solution if I ever get round to it as I will do it myself is to cut the cupboard doors shorter mabye the 20mm suggested or 10mm for a double and then put the return vent in the roof of the cupboard..

My wife said doors including cupboards cut short would look weird and said not an option, so best check first! If you're doing a roof vent that means it needs to be ducted back to the system, if you put a vent in the wall back towards the return that's ok but consider noise.

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#2654471 11-Feb-2021 10:18

how much noise/light is the outside the bedroom doors?

why do they need to be close at night?

timmmay

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#2654480 11-Feb-2021 10:36

Jase2985:

how much noise/light is the outside the bedroom doors? why do they need to be close at night?

In our house the bedrooms are adjacent to the main lounge, so whatever we're watching on TV would go through the grill. The door / wall is pretty decent sound insulation, which is why it's closed, but cut a hole and that gets worse. We use small lamps so light not really an issue.

decibel

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#2654638 11-Feb-2021 13:55

Tricky questions - we installed a ducted system 6 years ago and love it but we don't have outlets in individual bedrooms (hallway only and we sleep with our doors open.)

Do you have a concrete floor or can you put a return under the floor?

timmmay

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#2654645 11-Feb-2021 14:05

decibel:

Tricky questions - we installed a ducted system 6 years ago and love it but we don't have outlets in individual bedrooms (hallway only and we sleep with our doors open.)

Do you have a concrete floor or can you put a return under the floor?

Interesting, why did you put in a ducted unit with a single duct? Your design would be quite different from any other ducted unit, you don't need returns.

We could put a return under the floor easily enough, but then we'd need to run a 200mm duct from under the floor up to the ceiling cavity where the ducted unit lives. That's a pretty big pipe. I'd just put the return directly into the ceiling if I went that way.

I'm fairly confident that I'm going to order the Tamarak wall return grills from the US and install them low down, so the conditioned air is drawn across the room.

timmmay

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#2654939 12-Feb-2021 08:35

Tamarack have helpfully given me the shipping sizes and weights for the 12x6 wall vents so I could work out shipping.

1 unit- weight 5 lbs, box size 14 inches x 8 inches x 6 inches
3 units- weight 14 lbs, box size 14 inches x 8 inches x 20 inches

Shipping for grills (three / one) all NZD:

Youshop express $170 / $86
Youshop boat $97 / $57
ShipItTo $163 with DHL / $100 - 5 - 10 days
Amazon ship the 12x4 for $80 / $40

So cheapest total for three grills with shipping less than a month is $200 for the product and $163 or NZ$363, one grill $65 for the product and $86 shipping or $150 for one. Not cheap.

The 12x4 from Amazon is $138 for one or $387 for three. So about the same as the other options as the product is more expensive but shipping cheaper. I've asked if Tamarack can let Amazon ship the 12x6 internationally.

Buying locally and making something similar a wall grill is about $85, you need two, so my three rooms would be $510 and you still need dampening materials and to block off the wall cavity so you're not moving dust through. So maybe it's not too bad a deal to get from the USA.

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