ᐅ Split air conditioning system and mechanical ventilation with heat recovery
Created on: 16 Mar 2023 11:30
R
Rafaelsen
Hello everyone,
Does anyone have experience with a split air conditioning system combined with a central controlled residential ventilation system with heat recovery?
The main question is whether the controlled residential ventilation can distribute the cool air from the air conditioner and how well or poorly this works.
My idea: Because of the simplicity and short distances, I am considering a split air conditioning system with 2 indoor units.
The outdoor unit would be placed on the garage, and from there it is only about 50 cm (20 inches) through the wall into the bedroom upstairs and the living room downstairs. Power supply is also available. I want to avoid major effort and long duct runs to actively cool all rooms. The children’s rooms are not as easy to reach. It would be possible via an external duct on the outside wall, but I want to avoid that for aesthetic reasons.
The house was built in 2018 and exceeds the KfW 55 efficiency standard.
The primary energy demand is calculated at 42 kWh/m² (square meter) and the values from recent years confirm this.
We have 178 m² (1,914 square feet) of living space according to the living space ordinance and about 212 m² (2,282 square feet) of floor area. No basement and a gable roof are present, which explains the discrepancy.
Heating is provided by a ground-source heat pump with a water circuit, which is also equipped with a cooling function.
Cooling via the underfloor heating works satisfactorily and keeps the temperature around 24°C (75°F) even in midsummer.
However, it requires consistent shading and following recommendations. Once the heat has entered, it takes several days for the cooling system to lower the temperature again.
In 2022, we consumed 2,169 kWh of electricity and generated 9,408 kWh of heat for heating and domestic hot water.
The building is therefore comparatively efficient in terms of insulation.
We still want to get advice regarding the air conditioning. Both rooms are about 40 m² (430 square feet), and the question arises whether it makes sense to choose a more powerful air conditioner to have more cold air for distribution?
The controlled residential ventilation also supports this to some extent. In summer, it cools the outside air by a good 8°C (14°F).
The air volume flow is approximately 180 m³ (6,360 cubic feet) per hour on automatic setting.
Would the controlled residential ventilation noticeably distribute the cool air from the air conditioner and cool the other rooms, or would we rather get cooling zones within the house?
Thank you very much in advance.
Does anyone have experience with a split air conditioning system combined with a central controlled residential ventilation system with heat recovery?
The main question is whether the controlled residential ventilation can distribute the cool air from the air conditioner and how well or poorly this works.
My idea: Because of the simplicity and short distances, I am considering a split air conditioning system with 2 indoor units.
The outdoor unit would be placed on the garage, and from there it is only about 50 cm (20 inches) through the wall into the bedroom upstairs and the living room downstairs. Power supply is also available. I want to avoid major effort and long duct runs to actively cool all rooms. The children’s rooms are not as easy to reach. It would be possible via an external duct on the outside wall, but I want to avoid that for aesthetic reasons.
The house was built in 2018 and exceeds the KfW 55 efficiency standard.
The primary energy demand is calculated at 42 kWh/m² (square meter) and the values from recent years confirm this.
We have 178 m² (1,914 square feet) of living space according to the living space ordinance and about 212 m² (2,282 square feet) of floor area. No basement and a gable roof are present, which explains the discrepancy.
Heating is provided by a ground-source heat pump with a water circuit, which is also equipped with a cooling function.
Cooling via the underfloor heating works satisfactorily and keeps the temperature around 24°C (75°F) even in midsummer.
However, it requires consistent shading and following recommendations. Once the heat has entered, it takes several days for the cooling system to lower the temperature again.
In 2022, we consumed 2,169 kWh of electricity and generated 9,408 kWh of heat for heating and domestic hot water.
The building is therefore comparatively efficient in terms of insulation.
We still want to get advice regarding the air conditioning. Both rooms are about 40 m² (430 square feet), and the question arises whether it makes sense to choose a more powerful air conditioner to have more cold air for distribution?
The controlled residential ventilation also supports this to some extent. In summer, it cools the outside air by a good 8°C (14°F).
The air volume flow is approximately 180 m³ (6,360 cubic feet) per hour on automatic setting.
Would the controlled residential ventilation noticeably distribute the cool air from the air conditioner and cool the other rooms, or would we rather get cooling zones within the house?
Thank you very much in advance.
Rafaelsen schrieb:
Anyone with any experience?
Anyone who has both an air conditioning system and a mechanical ventilation with heat recovery? May I ask if and how you have solved this?
We have a mechanical ventilation system with heat recovery and are considering a split air conditioner. The last few nights have been really rough.
Just do it: with us, the mechanical ventilation system runs 24/7, 365 days a year. In summer, when it gets warm, the air conditioning turns on and stays on 24/7 until it cools down again (or there is a sudden drop in temperature).
The air exchange rate of a mechanical ventilation system in a typical single-family house is far too low to be worth worrying about.
The air exchange rate of a mechanical ventilation system in a typical single-family house is far too low to be worth worrying about.
R
Rafaelsen26 Jun 2023 10:39Hello everyone.
Our Panasonic air conditioning system has been running since mid-April, and we are very satisfied.
We installed a floor-standing unit upstairs and a wall-mounted unit in the living room downstairs, each connected to an outdoor unit.
After some testing, we start the units during hot afternoons around 3 p.m.
The living and bedrooms cool down within 10 minutes.
The rest of the house takes about 40 minutes to reach a comfortable temperature.
However, these rooms are about 1 degree warmer than the rooms with the units.
The ventilation works as expected, distributing the cool air throughout the whole house.
The electricity consumption is negligible. In June, we used about 60 kWh, and the units ran every day until sunset.
That is necessary! If you turn off the units during the day, the house heats up very quickly again. In the evening, when the sun is gone, it stays cool until morning.
Both units are so efficient that you can simply leave them running.
Since the house cools down quickly, it doesn’t make sense to run the system all day. Running it shortly before coming home is enough.
So, we are very happy and can recommend this combination to everyone. 🙂
Our Panasonic air conditioning system has been running since mid-April, and we are very satisfied.
We installed a floor-standing unit upstairs and a wall-mounted unit in the living room downstairs, each connected to an outdoor unit.
After some testing, we start the units during hot afternoons around 3 p.m.
The living and bedrooms cool down within 10 minutes.
The rest of the house takes about 40 minutes to reach a comfortable temperature.
However, these rooms are about 1 degree warmer than the rooms with the units.
The ventilation works as expected, distributing the cool air throughout the whole house.
The electricity consumption is negligible. In June, we used about 60 kWh, and the units ran every day until sunset.
That is necessary! If you turn off the units during the day, the house heats up very quickly again. In the evening, when the sun is gone, it stays cool until morning.
Both units are so efficient that you can simply leave them running.
Since the house cools down quickly, it doesn’t make sense to run the system all day. Running it shortly before coming home is enough.
So, we are very happy and can recommend this combination to everyone. 🙂
Dogma schrieb:
Just do it. In our home, the mechanical ventilation with heat recovery runs 24/7, 365 days a year, and in the summer, when it gets warm, the air conditioning switches on and stays on 24/7 until it cools down again (or there’s a sudden drop in temperature).
The air exchange rate of mechanical ventilation in a typical single-family house is far too low to even be a concern. That already sounds great 🙂 Thanks!
Rafaelsen schrieb:
Our Panasonic air conditioning system has been running since mid-April, and we are very satisfied.
Upstairs we installed a floor-standing unit and downstairs in the living room a wall-mounted unit.
Each unit is connected to its own outdoor unit. May I ask why you chose a floor-standing unit? Doesn’t it feel like it’s always in the way somehow?
From what I know abroad, these systems are almost always installed on the wall.
And what do you think about having one outdoor unit with two indoor units—do you think the capacity of a single outdoor unit is sufficient?
Where did you install your outdoor units?
KoalasAreCute26 Jun 2023 12:49Yaso2.0 schrieb:
What do you think about one outdoor unit and two indoor units? Do you think the outdoor unit’s capacity will be enough? That depends on how large the outdoor unit is. Ours can easily handle up to five indoor units. It is correspondingly more expensive because the capacity basically matches the outdoor unit’s power.
R
Rafaelsen26 Jun 2023 13:39Yaso2.0 schrieb:
May I ask why you chose a floor-standing unit? Doesn’t it feel like it’s always in the way?
From my experience abroad, these are usually wall-mounted.
What do you think about one outdoor unit and two indoor units—do you think the capacity of a single outdoor unit is enough?
And where did you install your outdoor unit? Hello,
The floor-standing unit was chosen due to the sloped ceiling and is now located under the Velux window.
A wall-mounted unit would have been less expensive and more efficient, but unfortunately, there was no way to install one.
The outdoor units are placed on the garage, so the distances were very short. There was also plenty of space.
The decision for a mono-split system was simply based on price and efficiency. One outdoor and one indoor unit are cheaper and more efficient than one outdoor and two indoor units.
The house details are in the first post. The floor-standing unit has 2.5 kW (8,530 BTU/h) and the wall unit 3.5 kW (11,950 BTU/h).
Best regards
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