ᐅ How many cubic meters per hour do I need for good indoor air quality?
Created on: 17 Dec 2017 15:45
C
Christian NW
Hello everyone,
I have read a lot about controlled residential ventilation with heat recovery, but I still don’t fully understand the following:
How many cubic meters per hour (m³/h) of supply air are needed to ensure good, continuously fresh air in the various rooms, especially in the bedrooms throughout the entire night?
Here are my rooms with their typical usage and sizes. Maybe you have specific practical experience or calculation values:
Upstairs:
1. Parents’ bedroom (2 persons, 18 m² (194 ft²), 285 cm (9 ft 4 in) ceiling height)
2. Child’s bedroom (1 child, 18 m² (194 ft²), 285 cm (9 ft 4 in) ceiling height)
3. Study room (for 1 person, 10 m² (108 ft²), 285 cm (9 ft 4 in) ceiling height)
Downstairs:
4. Guest room (designed for 2 persons, 11 m² (118 ft²), 255 cm (8 ft 4 in) ceiling height)
5. Living room with an open L-shaped kitchen (ventilation should cover all 4 family members and possibly guests, total 55 m² (592 ft²), 255 cm (8 ft 4 in) ceiling height)
So far, I have read various recommendations ranging from 20 to 30 m³/h per person. But are these values intended for the respective person’s room?
Does that mean, for example, 2 x 30 m³/h = 60 m³/h for the parents’ bedroom?
And 4 x 30 m³/h = 120 m³/h for the living room?
Others calculate based on the room volume, but does this approach sufficiently consider the intensity of use?
What practical values or experiences do you have?
I want to ensure there is always good, fresh air in the bedrooms. The same applies to the children’s rooms as well as the “large” living room with the open kitchen. Especially in the living room, I am unsure what the appropriate air exchange rate in cubic meters per hour should be to adequately serve 4 adult family members plus occasional guests.
I hope you can help shed some light on this ;-)
Thanks in advance!
I have read a lot about controlled residential ventilation with heat recovery, but I still don’t fully understand the following:
How many cubic meters per hour (m³/h) of supply air are needed to ensure good, continuously fresh air in the various rooms, especially in the bedrooms throughout the entire night?
Here are my rooms with their typical usage and sizes. Maybe you have specific practical experience or calculation values:
Upstairs:
1. Parents’ bedroom (2 persons, 18 m² (194 ft²), 285 cm (9 ft 4 in) ceiling height)
2. Child’s bedroom (1 child, 18 m² (194 ft²), 285 cm (9 ft 4 in) ceiling height)
3. Study room (for 1 person, 10 m² (108 ft²), 285 cm (9 ft 4 in) ceiling height)
Downstairs:
4. Guest room (designed for 2 persons, 11 m² (118 ft²), 255 cm (8 ft 4 in) ceiling height)
5. Living room with an open L-shaped kitchen (ventilation should cover all 4 family members and possibly guests, total 55 m² (592 ft²), 255 cm (8 ft 4 in) ceiling height)
So far, I have read various recommendations ranging from 20 to 30 m³/h per person. But are these values intended for the respective person’s room?
Does that mean, for example, 2 x 30 m³/h = 60 m³/h for the parents’ bedroom?
And 4 x 30 m³/h = 120 m³/h for the living room?
Others calculate based on the room volume, but does this approach sufficiently consider the intensity of use?
What practical values or experiences do you have?
I want to ensure there is always good, fresh air in the bedrooms. The same applies to the children’s rooms as well as the “large” living room with the open kitchen. Especially in the living room, I am unsure what the appropriate air exchange rate in cubic meters per hour should be to adequately serve 4 adult family members plus occasional guests.
I hope you can help shed some light on this ;-)
Thanks in advance!
C
Christian NW17 Dec 2017 22:29Is the second calculation completely wrong? I’m just trying to understand why there are two methods.
Can someone explain what the 25 m³ per person means?
When is this type of calculation used?
And when is the one with the room volume multiplied by a factor of 0.3 applied?
Let’s assume that it’s not the guest room, but the regularly used children’s room, which has 10 m² (108 sq ft) and 26 m³ (918 cu ft).
Would this regularly used room then require 25 m³/h (because of 25 m³ per person) or only 7.8 m³/h (25 × 0.3)?
Can someone explain what the 25 m³ per person means?
When is this type of calculation used?
And when is the one with the room volume multiplied by a factor of 0.3 applied?
Let’s assume that it’s not the guest room, but the regularly used children’s room, which has 10 m² (108 sq ft) and 26 m³ (918 cu ft).
Would this regularly used room then require 25 m³/h (because of 25 m³ per person) or only 7.8 m³/h (25 × 0.3)?
T
toxicmolotof18 Dec 2017 07:41Christian NW schrieb:
Is the second calculation completely wrong? I'm just trying to understand why there are two different methods.
Can someone explain what the 25 m3 per person refers to?
When is this type of calculation used?
And when is the one with room volume multiplied by a factor of 0.3 applied?
Let's assume that instead of the guest room, the regularly used children's room has 10 m2 (108 ft2) and 26 m3 (918 ft3).
Would this regularly used room then require 25 m3/h (880 ft3/h) (= because of 25 m3 per person) or only 7.8 m3/h (275 ft3/h) (= 26 × 0.3)?If the children's room is constantly in use, you might be doing something wrong. At least in Germany, school attendance is mandatory and most children have hobbies.Of course, you can also over-dimension, but then you always have fresh air...
Speaking of fresh air. How do you define fresh air? That also affects your calculation.
×0.3 => room-based calculation
×25 => whole-house calculation
That's how I understood Lumpi.
Yes, it depends on what is getting larger. If four people live in a 50m² (540 ft²) house, the ventilation rate should be set at 100m³/h (59 cfm) instead of just 0.3 air changes per hour, which is about 30–40m³/h (18–24 cfm). Realistically, it’s closer to 140m³/h (82 cfm) for four people, which results in around 350m³ (12,360 ft³), corresponding roughly to 100m³/h (59 cfm) at 0.3 air changes per hour.
The original poster (OP) would have only needed to look further, considering an average of eight rooms per house and assuming 2–4 people per room, to see what the total requirement would be. Such ventilation systems don’t even exist for single-family homes.
The original poster (OP) would have only needed to look further, considering an average of eight rooms per house and assuming 2–4 people per room, to see what the total requirement would be. Such ventilation systems don’t even exist for single-family homes.
B
Bieber081518 Dec 2017 10:53Has the CO2 calculator from the state of Lower Saxony already been mentioned here? Linking is not allowed, but it can be found quickly using the phrases mentioned.
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