Question for those with a SmartVent or unit that brings outside air in

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Wolf555

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#261395 25-Nov-2019 13:47

We have a basic smartvent installed in our house (previous owners installed it) that has the ceiling air and outside air.

I have it set so it switches to outside air when the ceiling gets over 22 degrees at the moment but I'm not convinced it's actually pulling in air from outside vs the air from the ceiling that's currently about 60 degrees.

How do you test this? The panel says it's on outside vent but if I put my hand up to the vents in the house, the air coming out of it feels MUCH hotter than the air outside, like extremely warm. I'm temped to actually leave the whole thing turned off (side note, do you guys run yours over summer? we have heatpumps we use as aircon and again I feel this is making them work harder too) as I feel it's heating the house up. It's only about 20 degrees outside at the moment so I wouldn't expect the air coming out to feel like it's actually heated air, right?

Can anyone tell me what theirs feels like or how to test it's actually pulling air from outside vs just the ceiling, regardless of what the panel says?

timmmay

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#2360472 25-Nov-2019 13:52

Get an IR thermometer from Jaycar to check it. They have some reasonably priced. I don't have this problem because I have a super simple system, the air always comes from outside, there's no ceiling air option. My options are on or off. I did it this way myself as the ceiling cavity is old, smelly, and dirty.

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kiwijunglist

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#2360486 25-Nov-2019 14:16

It might be the air is heating up as it travels though the ducting in the ceiling space.

Why don't you just either climb into the ceiling and check, or check the external intake vent?

Also compare the temperature between ceiling mode and outside mode (if that is possible).

HTPC / Home automation (home assistant) enthusiast.

Wolf555

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#2360496 25-Nov-2019 14:39

I went and checked the outside vent with it on vs turned off and when switched on it's definitely sucking air in, so it at least appears to be working but I swear the air coming out of the vents feels much hotter than outside.

Is there any advantage to running these systems over summer if I'm trying to prevent the house from heating up? We can have the aircon going and cooling the room down but then I stick my hand up to the vent and feel all this hot air coming out and it seems like a waste?

billgates

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#2360497 25-Nov-2019 14:46

Is the SmartVent system connected through an heat exchanger unit where in your home's stale air goes through return ducts via the heat exchanger, fresh air gets pulled in from outside through supply duct via the heat exchanger and the heat from your stale air is then transferred to the fresh air coming inside of the house. This is great for winters but for summers you want a summer bypass kit which is usually an extra add on you have to purchase where stale air heat will not be transferred with fresh incoming air in the heat exchanger.

Do whatever you want to do man.

Wolf555

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#2360501 25-Nov-2019 15:06

We don't have any return ducts inside the house, so I would assume no?

Jase2985

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#2360523 25-Nov-2019 15:35

what kind of ducting is it? i suspect the hot roof air is transferring its heat through your ducting into the in coming air. The motor etc is also likely very hot and helping with the transfer.

timmmay

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#2360524 25-Nov-2019 15:35

I think you should get an IR thermometer to objective measure the temperatures, as just holding your hand there is subjective. Also check for leaks / rips between the intake and the motor.

I have my ventilation system working all day in summer. Not sure if it helps reduce temperatures, but I have my fan running half speed. I might jack it back up to max. I think it helps a little, but the volume of outside air which is fairly warm vs the sun, the sun is much hotter. We still need the air conditioner. In winter we only use it about 3-4 hours a day, in the middle of the day.

Even with the air conditioner being used a lot we find summer power bills a lot lower than winter.

Geekeneer

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#2360539 25-Nov-2019 16:10

I have the same issue, except I have no controller for my unit anywhere, so I do not know what it is.

I was actually going to post on GZ asking here, as I have no clue regarding these systems.

All I have is a single vent, at the top most floor of my rented townhouse. The vent is round, and blows air continuously.

I have no clue whether there is a fan or not in the ceiling, or whether there is any controller at all, or if it's just a positive pressure system.

With the warmer days, the vent is blowing hot air, which I assume is hot ceiling air, making the top floor rather balmy. You can feel the difference in air temp once you get down the stairs, a very noticeable difference.

In winter, it blew cold air, making the whole top floor rather cool.

I have literally just emailed the landlord to find out what system this is. When I occupied the house a few months back, all I was told is that it doesn't need to be controlled any how.

But the temperature differences are rather uncomfortable now.

snnet

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#2360576 25-Nov-2019 18:14

More than likely the ducting has come off between the exterior intake grill and the damper motor switch which changes between outside air and ceiling space air...

yann

132 posts

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#2360602 25-Nov-2019 19:13

Hmm, I wonder if it is a basic SmartVent unit, then it is pushing through some of the ceiling space air. I think there are addons which you can put in.

Just had a quick look, and something like this one at Bunnings is a Summer kit, which brings in cooler air from outside.

https://www.bunnings.co.nz/smartvent-sv04-summer-upgrade-kit_p00294728

I think once you add this in, it should feature on the control console, and so you then select how it works. I think a similar thing with the Winter heat-transfer kits, though that one is to move warm air from one room to others.

Yann

Wolf555

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#2360614 25-Nov-2019 19:52

snnet:
More than likely the ducting has come off between the exterior intake grill and the damper motor switch which changes between outside air and ceiling space air...

If this were the case I wouldn't be able to feel air being sucked in through the outside vent correct?

bfginger

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#2371429 9-Dec-2019 23:32

air from the ceiling that's currently about 60 degrees.

That's extremely hot for New Zealand. Is it a black roof? I'd want above code insulation to stop that heat leaking into the living area.

timbosan

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#2371493 10-Dec-2019 09:08

Wolf555:

I went and checked the outside vent with it on vs turned off and when switched on it's definitely sucking air in, so it at least appears to be working but I swear the air coming out of the vents feels much hotter than outside.

Is there any advantage to running these systems over summer if I'm trying to prevent the house from heating up? We can have the aircon going and cooling the room down but then I stick my hand up to the vent and feel all this hot air coming out and it seems like a waste?

We have an Sayr system (installed by Landlord), and in summer (well, at the moment at least) it does really help in the evenings and at night; it takes the cooler air (Sayr's take it from the roofspace) and you can definitely feel it; its a real help now the weather is changing (I am in Auckland). I can feel the air is cooler coming out of the vents.

I have a LDC controller on the wall that shows the house, ceiling and outside temps, plus lets you set a target temp. There is no heater on this unit. When the unit sees the ceiling temp is outside the target range of the house it either goes into filter mode or turns off (for example if the roof is 40 and the house is already > 20).

I would get your's checked, as someone else said it may have a leak or disconnected pipe.