We already had a brief discussion about this topic in the construction costs thread this week, but now I want to address it separately. Originally, we weren’t sure whether we even wanted cooling, especially after experiencing another “summer of the century”… so I definitely want to have a plan for it. Here are the basic details:
- Northwest inland area of Lake Constance at 660m (2,165 ft)
- KfW40+ monolithic construction with ground-source heat pump, 2 full stories plus attic, both floor slabs made of concrete
- Shading is planned; almost all rooms have windows with different orientations, allowing shading without making the rooms completely dark
- I will mainly be working from home (and working from the garden is not an option)
The actual cooling demand is still unclear. Compared to the current situation, it will certainly improve significantly due to the elevation, distance from the lake, and open surroundings, which should reduce heat and allow much better cooling at night. The main goal is to eliminate peak temperatures; maintaining a constant 22°C (72°F) indoors is not the objective. Daytime temperatures of 25-26°C (77-79°F) are acceptable.
In principle, I also think that with proper shading we are not in a bad position; the roof should prevent heat from pressing into the living areas.
For a few years now, our office has had underfloor cooling, which can be implemented quite efficiently using the ground-source heat pump, so that was our first approach. Unfortunately, the cost for the cooling increased from the original estimate of 2,000 to about 4,000. That seems a bit too expensive for me. Therefore, the next idea was to simply get one of those portable monobloc air conditioning units and somehow seal the hose at the window. You could get a good unit for well under 1,000€. A split air conditioner would of course be more practical, but it would require a core drill (expensive), and I’m unsure where it could be installed. Ideally, it would be installed in the upper hallway, but there we have a large fixed glazing panel in the stairwell. If it had to be somewhere, it would probably be in a corner of the study (labeled Child 2 on the plan), where the architect has drawn in the bed. But then only the study would be cooled. Also, is that even easily possible in an energy-efficient house like this, or would I run into problems with the KfW funding (keyword: deterioration prohibition)?
At the moment, I’m leaning towards the portable solution because it’s affordable and flexible. Any opinions or questions?
- Northwest inland area of Lake Constance at 660m (2,165 ft)
- KfW40+ monolithic construction with ground-source heat pump, 2 full stories plus attic, both floor slabs made of concrete
- Shading is planned; almost all rooms have windows with different orientations, allowing shading without making the rooms completely dark
- I will mainly be working from home (and working from the garden is not an option)
The actual cooling demand is still unclear. Compared to the current situation, it will certainly improve significantly due to the elevation, distance from the lake, and open surroundings, which should reduce heat and allow much better cooling at night. The main goal is to eliminate peak temperatures; maintaining a constant 22°C (72°F) indoors is not the objective. Daytime temperatures of 25-26°C (77-79°F) are acceptable.
In principle, I also think that with proper shading we are not in a bad position; the roof should prevent heat from pressing into the living areas.
For a few years now, our office has had underfloor cooling, which can be implemented quite efficiently using the ground-source heat pump, so that was our first approach. Unfortunately, the cost for the cooling increased from the original estimate of 2,000 to about 4,000. That seems a bit too expensive for me. Therefore, the next idea was to simply get one of those portable monobloc air conditioning units and somehow seal the hose at the window. You could get a good unit for well under 1,000€. A split air conditioner would of course be more practical, but it would require a core drill (expensive), and I’m unsure where it could be installed. Ideally, it would be installed in the upper hallway, but there we have a large fixed glazing panel in the stairwell. If it had to be somewhere, it would probably be in a corner of the study (labeled Child 2 on the plan), where the architect has drawn in the bed. But then only the study would be cooled. Also, is that even easily possible in an energy-efficient house like this, or would I run into problems with the KfW funding (keyword: deterioration prohibition)?
At the moment, I’m leaning towards the portable solution because it’s affordable and flexible. Any opinions or questions?
We were / are in a similar situation: completed last year, KfW40 standard, but timber frame construction. Our energy consultant told us that air conditioning is not feasible with KfW40. However, we had the installer and electrician prepare the house so that later on, adding air conditioning units in the upper floor and living room could be done fairly easily. We could also use passive cooling, but for now we decided against it.
As I mentioned in another thread recently, we were very pleasantly surprised this summer by what can be achieved with shading and cross-ventilation. Temperatures were quite comfortable. It will probably be the humidity that makes us reconsider air conditioning...
As I mentioned in another thread recently, we were very pleasantly surprised this summer by what can be achieved with shading and cross-ventilation. Temperatures were quite comfortable. It will probably be the humidity that makes us reconsider air conditioning...
DaHias81 schrieb:
Our energy consultant told us that using air conditioning is not possible with KfW40.Yes, that’s nonsense multiplied by ten... but that’s how it is. You are allowed to have the unit installed for heating, even with subsidies. However, if you want to use the same unit again for cooling, of course, that’s not allowed.WilderSueden schrieb:
Probably yes. And of course, $3,000 more on a project with a total budget of $550,000 (all-in including kitchen, land, additional costs...) is not huge. On the other hand, I once again have the feeling that the planning costs are getting out of hand... I can definitely understand that. It’s always easy to talk about “ratios” when dealing with individual trades. But in the end, it’s the total sum that counts, and that is usually considerable. A few thousand more here, a few thousand more there...
Ultimately, it’s more about the principle and weighing the cost-benefit ratio. And the latter is probably best achieved with a standard split air conditioning system, as already discussed in the other thread.
Maybe you should simply get an HVAC specialist to come by, if they even have time before Christmas 🙁 and discuss the project onsite? After all, even with full glazing, there should be options to route the necessary pipes through the adjacent rooms, right? By the way, what about the floor plan on the lower side? Is the shown section oriented correctly according to the cardinal directions?
W
WilderSueden29 Aug 2022 10:59The floor plan is not oriented, but the top of the plan corresponds to NNW. This raises the question of whether such a device can even be installed, as the house is built right up to the minimum 2.5m (8 feet) boundary line.
At the bottom right of the plan is the study for my girlfriend, and at the very bottom are the two bedrooms, where no air conditioning will be installed (or I might end up living in the house alone...).
And yes, the best option would probably be proper professional advice, but that won’t be possible in time before I have to make a decision. Planning ahead would have been even better, of course, but air conditioning was never a priority for us, and I’m still not really sure if we will actually need it. It’s simply a bit cooler up there. That’s why a retrofit solution would actually make the most sense—I’m just not sure what the financial impact would be.
At the bottom right of the plan is the study for my girlfriend, and at the very bottom are the two bedrooms, where no air conditioning will be installed (or I might end up living in the house alone...).
And yes, the best option would probably be proper professional advice, but that won’t be possible in time before I have to make a decision. Planning ahead would have been even better, of course, but air conditioning was never a priority for us, and I’m still not really sure if we will actually need it. It’s simply a bit cooler up there. That’s why a retrofit solution would actually make the most sense—I’m just not sure what the financial impact would be.
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