supply air or exhaust air?

[Erik We]

Hello, I have a house that is partly from the 1930s. To/from two of the bedrooms on the upper floor and to/from the hallway, there are ventilation ducts going up to the attic where they connect to the chimney. Two connections to the chimney, so the duct to/from one of the bedrooms joins together in the attic. In the bedrooms, these can be regulated with the help of a rotary damper/louvered damper. I have seen the same solution in a house from 1953 and have always thought that they are supply air channels. Could some kind soul confirm or deny that?
Thanks in advance.

 

[Jan_G]

These are exhaust air ducts. Possibly, there might have been some mechanical device helping to extract a bit more, like a chimney wind spinner: https://www.bauhaus.se/vindsnurra-f...AuARTp92TDugtzF2pChpK2w7TAYCoyjRoCS8AQAvD_BwE

 

[Erik We]

Exhaust air usually comes from kitchens and bathrooms. Why was exhaust air built from bedrooms?

 

[Jonatan79]

You probably have poor or no draft in those channels unless you keep the chimney warm. Block the channels and create new ones in the window frame or outer wall in the bedrooms.

 

[AndersS]

Exhaust air is usually from the kitchen and bathroom. Why was exhaust air built from the bedroom?

They built with natural ventilation, so they built in the 60s and earlier.

 

[Erik We]

Look there. I learned something new today. Thanks for your answers.

 

[Isakare]

You probably have poor or no draft in those channels if you don't keep the chimney warm. Seal the channels and create new ones in the window frame or outer wall in the bedrooms.

No, no, no, stop now.
Channels upwards, even in an unheated chimney stack, are 10 times better than vents in wall/window.
Together with vents in wall/window, you get natural ventilation, the chimney effect.

 

[Jonatan79]

No, no, no, stop it now.
Channels upward, even in an unheated chimney stack, are 10 times better than vents in the wall/window.
Together with vents in the wall/window, you get natural draft, the chimney effect.

This is by no means true for everyone, why do you think fans are installed to achieve a humane indoor environment after around 1980?

 

[Oldboy]

why do you think fans were installed to create a humane indoor environment after around 1980?

Because from the '80s, almost no houses were built with chimneys for permanent heating with wood or oil burners. Virtually all detached houses/terraced houses were based on electric heating.

 

[Jonatan79]

We can ask TS if he experiences good ventilation in his house, especially in the bedrooms. Does TS feel any draft at all in the so-called "exhaust air ducts" in the bedrooms?

 

[Isakare]

Because from the 1980s onwards, almost no houses were built with chimneys for permanent heating with wood or oil burners. Virtually all houses/rowhouses were based on electric heating.

Exactly, and rooms are not built around the chimney. In older houses, all rooms had contact with the chimney, which only has pipes going straight up. If the house was larger, it had 2 chimneys. The air supply was less tight windows compared to today.

 

[Jonatan79]

Exactly, and the rooms are not built around the chimney. In houses from the past, every room had contact with the chimney, which only has pipes straight up. If the house was larger, it had 2 chimneys. The air supply was less tight windows than today.

In our house that was remodeled/extended in 1969 with the same thinking, without a fan in the bathroom of course, there was poor air exchange, no draft in the exhaust vent in the bedroom ceiling, and fairly tight windows. Very nice to wake up without oxygen in the morning and a musty cozy smell, some seem to like it, not me.

 

[Dublin]

It would be interesting to know what type of heating TS has. I myself live in a house from 1908 with natural ventilation and several exhaust channels in the chimney, and it works well when we have a fire - we have a pellet boiler and a tiled stove. But when we don't have a fire, the natural ventilation doesn't work as effectively, of course.

 

[AndersS]

Older houses have various solutions, and over time, conditions have usually changed. Don't know what has been done with ts house, so our own will serve as an example.
Built in the '60s with a chimney with six ducts, two of which were exhaust and one open fireplace where the damper also functioned as an exhaust.
Then there are four exhaust channels via roof ducts and the kitchen fan.
All bedrooms had roof channels!
Supply air duct only in the basement; the rest of the house had leakages where air came in.
Today, additionally insulated and sealed, with new windows and a cold chimney thanks to geothermal heating. Then, two bathrooms got exhaust fans, and the fireplace got an insert where the room received a new supply air duct. And the new windows in the bedrooms have supply air vents.

This was a long story, but the purpose was to show how an older house can have changed over time. Depending on what has been done, you need to adapt both supply air and exhaust with passive ventilation according to new conditions with each change. Also, consider the floor plan, which may also have changed.
So, to answer ts question and similar ones, a more detailed review of the house is needed, preferably on site.

 

[TypRätt]

If there are already channels going up to the attic, I would have modified that solution instead of making holes in the wall. That is, run some spiro and put a fan in the attic and take in fresh air from the side of the house. (Preferably a side that is away from roads or other noisy places)