What min temperature setting to use for Smartvent (or similar) over winter?

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Wolf555

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#270366 6-May-2020 10:12

We have the same Smartvent as in this video, which says over winter to set the minimum temperature to 5 degrees - https://www.youtube.com/watch?v=2DvOXBDYUnI&feature=emb_logo

However I checked it this morning and it was blowing freezing air from the ceiling that was about 10 degrees. I understand they're not for heating, and we have heatpumps for that instead, but my question is what do you guys set it at so you're not cooling your rooms, yet at the same time not losing the benefit of reducing condensation? Because if I set it to turn off if it gets too cold, then it defeats the purpose of having it over winter right? Am I missing something?

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#2477655 6-May-2020 10:45

OP seems to have discovered the Achilles Heel of these systems, which is why I'd never have one in my house.

Any air below inside ambient (18C?) is going to feel cold, so unless you shut the system off for most of the winter, it's going to feel cold.

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MikeAqua

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#2477729 6-May-2020 12:28

We had a smart vent that included an air-air heat exchanger for recovery of heat from outgoing air. We set our minimum operating temp to 16C.

Mike

shk292

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#2477734 6-May-2020 12:32

MikeAqua:

We had a smart vent that included an air-air heat exchanger for recovery of heat from outgoing air. We set our minimum operating temp to 16C.

Those are the ones that do seem worthwhile

MikeAqua

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#2477898 6-May-2020 15:07

shk292:

MikeAqua:

We had a smart vent that included an air-air heat exchanger for recovery of heat from outgoing air. We set our minimum operating temp to 16C.

Those are the ones that do seem worthwhile

Great unit. In sunny Nelson it made the whole house cosy, and dry.

Seriously considering one for our new house in Blenheim.

Mike

roderickh

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#2477920 6-May-2020 15:26

MikeAqua:

We had a smart vent that included an air-air heat exchanger for recovery of heat from outgoing air. We set our minimum operating temp to 16C.

Great unit. In sunny Nelson it made the whole house cosy, and dry.

Seriously considering one for our new house in Blenheim.

Do you have a link to the product? How much was it for installation? Cheers

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Kickinbac

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#2477939 6-May-2020 15:32

roderickh:

MikeAqua:

We had a smart vent that included an air-air heat exchanger for recovery of heat from outgoing air. We set our minimum operating temp to 16C.

Great unit. In sunny Nelson it made the whole house cosy, and dry.

Seriously considering one for our new house in Blenheim.

Do you have a link to the product? How much was it for installation? Cheers

It's probably a Smartvent Synergy which is their balanced heat recovery system.

Kickinbac

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#2477940 6-May-2020 15:33

I watched the youtube video by the OP. They basically just override the settings so the fan runs as much as possible. The result will be dry windows and a cold house. Cold air holds less moisture than warm air, therefore, less moisture to condense on a window. This really defeats the purpose of having a controller. A positive pressure system should be set up so that if the roof space temperature is lower than the indoor temperature the fan will switch off. If not, you are just pushing the heated air out of your home with cold roof air.

Rant... Positive pressure systems are really just an ambulance at the bottom of the cliff. They are a cheap(??!!) easy method to reduce moisture in the air. They don't solve the problems of draught sealing (air tightness) insulation, adequate heating etc. But to carry out all the necessary upgrades to a house can cost thousands of dollars. Unfortunately, every house has different issues and solutions and it's not easy to get good independent advice on what to do. There are plenty of official information on how to upgrade housing and positive pressure ventilation is never one of them... bathroom exhaust fans & kitchen hoods to remove moisture at the source, draught sealing, good curtains, upgrade insulation etc. https://www.energywise.govt.nz/at-home/simple-ways-to-lower-energy-bills/?gclid=EAIaIQobChMIrfTn66Oe6QIVhQsrCh1D9Al8EAAYASAAEgK3PfD_BwE

rb99

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#2477942 6-May-2020 15:38

Smartvent Balance or Smartvent Synergy. One recovers energy, the other recovers heat. I imagine to avoid hypothermia it'll be the more expensive one.

“The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness.” -John Kenneth Galbraith

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Wolf555

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#2477947 6-May-2020 15:40

Just to add some context, we did not purchase or install the system. It came in the house already.

I understand people don't like them, but we have it and may as well use it.

freitasm

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#2477952 6-May-2020 15:43

Kickinbac:

I watched the youtube video by the OP. They basically just override the settings so the fan runs as much as possible. The result will be dry windows and a cold house. Cold air holds less moisture than warm air, therefore, less moisture to condense on a window. This really defeats the purpose of having a controller. A positive pressure system should be set up so that if the roof space temperature is lower than the indoor temperature the fan will switch off. If not, you are just pushing the heated air out of your home with cold roof air.

Rant... Positive pressure systems are really just an ambulance at the bottom of the cliff. They are a cheap(??!!) easy method to reduce moisture in the air. They don't solve the problems of draught sealing (air tightness) insulation, adequate heating etc. But to carry out all the necessary upgrades to a house can cost thousands of dollars. Unfortunately, every house has different issues and solutions and it's not easy to get good independent advice on what to do.

It makes no sense really. You make a perfectly insulated house, then cook pasta for dinner and all that water goes into the air. How do you extract that as some extractors are really not great even at full force?

You can use dehumidifier (which also help with increasing temperature a degree or so, at the cost of energy). Or you can use these positive pressure systems - at the cost of pushing cold air into the house, defeating the heating. Or you could open a window - completely wasting the energy used in heating the house.

Is just me or the balance of a dry, cosy home versus a dry, cold home is very hard to achieve?

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shk292

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#2478018 6-May-2020 16:37

Part of the problem is the lack of double glazing. For those of us who have spent time living in UK/Europe, DG is everywhere. I'm not convinced that the air in UK houses is much less damp than here, but it's less of an issue because there are fewer cold surfaces for it to condense on

freitasm

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#2478026 6-May-2020 16:51

shk292:

Part of the problem is the lack of double glazing. For those of us who have spent time living in UK/Europe, DG is everywhere. I'm not convinced that the air in UK houses is much less damp than here, but it's less of an issue because there are fewer cold surfaces for it to condense on

Good point.

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Kickinbac

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#2478134 6-May-2020 19:36

shk292:
Part of the problem is the lack of double glazing. For those of us who have spent time living in UK/Europe, DG is everywhere. I'm not convinced that the air in UK houses is much less damp than here, but it's less of an issue because there are fewer cold surfaces for it to condense on

In the UK central heating is common plus the construction of their homes Is different, lots more use of brick and stone, plastered walls etc.

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#2478137 6-May-2020 19:50

I use positive pressure ventilation on a timer. In summer it runs morning and evening. In winter it runs during the day for a few hours, to make sure the air is dry and fresh, plus for a short time in the evening. That way we get fresh air and it's not so cold.

I'd rather have a system with a heat exchanger, but don't really want to pay for one, so a timer is an ok compromise. Plus we have double glazing, insulation, heating.

Handle9

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#2478166 6-May-2020 20:45

freitasm:

shk292:

Part of the problem is the lack of double glazing. For those of us who have spent time living in UK/Europe, DG is everywhere. I'm not convinced that the air in UK houses is much less damp than here, but it's less of an issue because there are fewer cold surfaces for it to condense on

Good point.

Gross generalisations follow:

New Zealand houses are junk. Until relatively recently houses were single glazed, uninsulated and didn't have heating. New Zealanders don't heat their houses, they heat their living rooms.

In other parts of the world they heat / cool the whole house, not just single rooms. PPV is lipstick on a pig.

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