ᐅ Is it possible to install air conditioning as an upgrade if a mechanical ventilation system with heat recovery is already installed?
Created on: 8 Aug 2021 07:32
M
McEgg
Hello,
we live in a KfW55 house with a controlled mechanical ventilation system. Since it gets too warm for me in the summer, I would now like to add air conditioning units.
I am planning a total of four units: in the three bedrooms upstairs and in the open living, dining, and kitchen area on the ground floor.
I have looked at units from Gree and would choose 2.7 kW units for the upstairs rooms and a 5.3 kW unit for the ground floor, based on the room sizes.
Now to the main question:
Does it make sense to install air conditioning if we already have a controlled mechanical ventilation system? Do the air conditioning units generally need to be sized larger because the ventilation system removes the cool air too quickly? Or does the controlled mechanical ventilation system prevent the rooms from cooling down effectively in the first place?
we live in a KfW55 house with a controlled mechanical ventilation system. Since it gets too warm for me in the summer, I would now like to add air conditioning units.
I am planning a total of four units: in the three bedrooms upstairs and in the open living, dining, and kitchen area on the ground floor.
I have looked at units from Gree and would choose 2.7 kW units for the upstairs rooms and a 5.3 kW unit for the ground floor, based on the room sizes.
Now to the main question:
Does it make sense to install air conditioning if we already have a controlled mechanical ventilation system? Do the air conditioning units generally need to be sized larger because the ventilation system removes the cool air too quickly? Or does the controlled mechanical ventilation system prevent the rooms from cooling down effectively in the first place?
Mycraft schrieb:
With today’s construction methods, a 3.5 kW unit should be sufficient for your living area, and for the bedrooms, the smallest available units, ideally around 2.0 kW. At least for us, the 3.5 kW for the living area matched the calculation (not just an estimate). For bedrooms of similar size as mentioned here, the smallest possible 1.8 kW units were barely sufficient, so we opted for the next size up (2.5 kW). The outdoor unit only needs to match the calculated cooling load, which may be less than the sum of the maximum output of all indoor units.
Yes, KfW-certified houses are both a blessing and a curse. You simply can’t get the heat out anymore, and when it’s over 30 degrees Celsius (86°F) for several days, you can’t cool the low-energy house down to below 20 degrees Celsius (68°F).
There are four of us and we’re home almost all day. So in summer, it’s constantly going in and out. Nobody really takes care of the shading except me.
I’m fortunate to have KNX installed in the house, though. I just need to get around to automating the shading. 🙄
@Mycraft @K1300S
Thanks for the input. A friend installs Gree air conditioning units, so I looked at those. The smallest model in the series I liked has 2.5 kW. But okay, for the ground floor maybe the slightly larger model with around 3.x kW would be better.
@driver55
Don’t ask. The awning was almost a drama on its own. But yes, we now have one or rather two pergola awnings. That was definitely one of the best purchases. Finally, some shade on the terrace. 🙂
There are four of us and we’re home almost all day. So in summer, it’s constantly going in and out. Nobody really takes care of the shading except me.
I’m fortunate to have KNX installed in the house, though. I just need to get around to automating the shading. 🙄
@Mycraft @K1300S
Thanks for the input. A friend installs Gree air conditioning units, so I looked at those. The smallest model in the series I liked has 2.5 kW. But okay, for the ground floor maybe the slightly larger model with around 3.x kW would be better.
@driver55
Don’t ask. The awning was almost a drama on its own. But yes, we now have one or rather two pergola awnings. That was definitely one of the best purchases. Finally, some shade on the terrace. 🙂
H
hampshire8 Aug 2021 18:20McEgg schrieb:
Nobody really takes care of the shading except me.Yes, that is a crucial difference between theory and practice, which I know all too well. No arguments help here.McEgg schrieb:
Nobody really takes care of the shading besides me.For the design of your air conditioning system, you either need to automate the shading using KNX or not consider any shading in the design. In the end, that makes a big difference.
hanse987 schrieb:
do not consider shading in the design. It makes a big difference in the end.No big difference??? For us, the difference between with and without shading is about 220 W/m² (20.45 W/ft²). I find that huge, especially when you consider the usual 60 to 80 W/m² (5.6 to 7.4 W/ft²) with shading.