ᐅ Reversible air-to-water heat pump vs. air conditioning unit with heating function
Created on: 12 Aug 2020 22:42
H
hendi1908
Hello everyone,
This is my first post here, and when it comes to house building, I am a complete beginner. I will likely have several questions for you in the future regarding the planning and construction of a solid masonry bungalow.
My first question has been on my mind since the beginning of the planning process:
What are your experiences or opinions about a reversible air-to-water heat pump with active cooling compared to an air conditioning system with heating function for the entire house?
I have read many reports on this topic, but every option has its pros and cons. My main concern is which solution is truly the most effective for cooling indoor temperatures during summer when outside temperatures reach around 40°C (104°F), especially with wall thicknesses of 30 to 36.5 cm (12 to 14.5 inches).
I have read that a ground-source (geothermal) heat pump is generally the most efficient, but it is more expensive to install than a reversible air-to-water heat pump. However, based on my experience in the USA (Florida), I am very impressed with an air conditioning system that also provides heating. So, I am uncertain whether a reversible air-to-water heat pump can cool indoor air just as effectively.
A few days ago, during a planning meeting on a day with 39°C (102°F) outside temperature, the representative from my masonry construction company said right away, “You really notice the air conditioning at these temperatures.” That comment surprised me somewhat because everyone usually wants to sell you the KfW construction standard and the most sustainable solution. In my opinion, it won’t help much if, for example, I end up sitting in the bungalow at 30°C (86°F) room temperature when it’s 35°C (95°F) outside, just because I have an air-to-water heat pump.
I would really appreciate any brief replies or shared experiences because practical experience means more to me than any reports or sales pitches promoting the latest technology.
Best regards
This is my first post here, and when it comes to house building, I am a complete beginner. I will likely have several questions for you in the future regarding the planning and construction of a solid masonry bungalow.
My first question has been on my mind since the beginning of the planning process:
What are your experiences or opinions about a reversible air-to-water heat pump with active cooling compared to an air conditioning system with heating function for the entire house?
I have read many reports on this topic, but every option has its pros and cons. My main concern is which solution is truly the most effective for cooling indoor temperatures during summer when outside temperatures reach around 40°C (104°F), especially with wall thicknesses of 30 to 36.5 cm (12 to 14.5 inches).
I have read that a ground-source (geothermal) heat pump is generally the most efficient, but it is more expensive to install than a reversible air-to-water heat pump. However, based on my experience in the USA (Florida), I am very impressed with an air conditioning system that also provides heating. So, I am uncertain whether a reversible air-to-water heat pump can cool indoor air just as effectively.
A few days ago, during a planning meeting on a day with 39°C (102°F) outside temperature, the representative from my masonry construction company said right away, “You really notice the air conditioning at these temperatures.” That comment surprised me somewhat because everyone usually wants to sell you the KfW construction standard and the most sustainable solution. In my opinion, it won’t help much if, for example, I end up sitting in the bungalow at 30°C (86°F) room temperature when it’s 35°C (95°F) outside, just because I have an air-to-water heat pump.
I would really appreciate any brief replies or shared experiences because practical experience means more to me than any reports or sales pitches promoting the latest technology.
Best regards
In this thread, it has been explained several times that hybrid or multiple solutions usually aren’t really practical (also economically speaking); otherwise, they would have long since established themselves on the market as a universal solution.
@UnfähigerBeamt Here, too, it is complicated, and from my point of view, I would first advise you to improve the insulation quality to better than KfW 40 standards. I had a house with 36 Poroton blocks and now have one below KfW 40. I couldn’t have imagined it, but the rooms cool down much less, so you also need to supply less heat. Regardless of the heating system, that would be my first step.
From this and the fact that we absolutely wanted a fireplace that we use often, the decision was made for a supporting infrared heating system, which is still designed as the main heating but is used less frequently.
Then we have a Daikin multi-split system in three areas, and for us, this system only works in this combination and fits our lifestyle.
I occasionally read that some people always need 23-24°C (73-75°F), which is different from our situation. I also often read that air-to-air heat pumps or air conditioning feel like a hairdryer, which is naturally meant negatively.
Ultimately, you really have to look at it closely yourself, preferably try living with it, because of course everyone is convinced of their own system and often other opinions don’t come into play. Everything is possible, and there are pros and cons to everything. The heat gain through windows also plays a role; for example, we often don’t need any additional heating from the end of February until November.
My opinion is: a high insulation standard and definitely a standalone controlled mechanical ventilation system with heat recovery AND an air conditioning system. Whether you still need an expensive air-to-water heat pump with or without underfloor heating depends entirely on you; for us, the fireplace answered that question, and we are very satisfied with our energy consumption.
I would always install a controlled mechanical ventilation system again, because the air quality is really noticeable to me and also gives me the good feeling of sitting on the sofa almost outdoors. That’s how it is for me!
Our air conditioning system cost around 10,000 (currency not translated), but it is equipped with generous units, uses almost no electricity due to photovoltaics, and in winter we use it selectively for additional heating, for example in the morning when the sun hasn’t yet brought enough warmth into the room or briefly in the evening. I don’t find it unpleasant, and even if a warm breeze were noticeable, I would find that pleasant. You can also consider where to place the units; additionally, they have a swing mode, etc. The power consumption is low, also because it runs at full power for only a short time and then continues on a low setting. Those are my experiences and the opinion that true cooling is only achievable with an air conditioning system.
By the way, we have a hot water system from an AroStor heat pump.
@UnfähigerBeamt Here, too, it is complicated, and from my point of view, I would first advise you to improve the insulation quality to better than KfW 40 standards. I had a house with 36 Poroton blocks and now have one below KfW 40. I couldn’t have imagined it, but the rooms cool down much less, so you also need to supply less heat. Regardless of the heating system, that would be my first step.
From this and the fact that we absolutely wanted a fireplace that we use often, the decision was made for a supporting infrared heating system, which is still designed as the main heating but is used less frequently.
Then we have a Daikin multi-split system in three areas, and for us, this system only works in this combination and fits our lifestyle.
I occasionally read that some people always need 23-24°C (73-75°F), which is different from our situation. I also often read that air-to-air heat pumps or air conditioning feel like a hairdryer, which is naturally meant negatively.
Ultimately, you really have to look at it closely yourself, preferably try living with it, because of course everyone is convinced of their own system and often other opinions don’t come into play. Everything is possible, and there are pros and cons to everything. The heat gain through windows also plays a role; for example, we often don’t need any additional heating from the end of February until November.
My opinion is: a high insulation standard and definitely a standalone controlled mechanical ventilation system with heat recovery AND an air conditioning system. Whether you still need an expensive air-to-water heat pump with or without underfloor heating depends entirely on you; for us, the fireplace answered that question, and we are very satisfied with our energy consumption.
I would always install a controlled mechanical ventilation system again, because the air quality is really noticeable to me and also gives me the good feeling of sitting on the sofa almost outdoors. That’s how it is for me!
Our air conditioning system cost around 10,000 (currency not translated), but it is equipped with generous units, uses almost no electricity due to photovoltaics, and in winter we use it selectively for additional heating, for example in the morning when the sun hasn’t yet brought enough warmth into the room or briefly in the evening. I don’t find it unpleasant, and even if a warm breeze were noticeable, I would find that pleasant. You can also consider where to place the units; additionally, they have a swing mode, etc. The power consumption is low, also because it runs at full power for only a short time and then continues on a low setting. Those are my experiences and the opinion that true cooling is only achievable with an air conditioning system.
By the way, we have a hot water system from an AroStor heat pump.
N
nordanney30 Apr 2025 10:49Sahitaz schrieb:
Yes, the question is whether the rooms with the supply air are exactly the rooms I want to cool? I would say, for the most part, yes. What about the exhaust air from the connected kitchen? And the other ducts?
Sahitaz schrieb:
The last point is more like 'I want the air-to-water heat pump because it is the base of the house ... if I have the air-to-air heat pump, I could use it additionally to relieve the air-to-water heat pump or shift it into more efficient operating ranges.' You don’t need to relieve the air-to-water heat pump. That doesn’t make sense. You just want to connect an air conditioner to the mechanical ventilation with heat recovery. THAT doesn’t work.
Cooling capacity of 2.5 kW, for example, with the mentioned device. That’s limited. You will never achieve real cooling without a dedicated air conditioning system or activated concrete core cooling.
And you will always feel the cooling effect.
N
nordanney30 Apr 2025 10:58Addendum: Before considering active cooling for the house, the planner (and of course you) should first focus on effective passive cooling. By that, I mean protection from summer heat. This can include the orientation of the house (I would never consider placing the main living area with a terrace fully facing the southern sun, only to have to rely on shading later because it gets too hot), roof overhangs, window size and positioning, and of course—as Arauki11 mentioned—the insulation standard and materials used, etc.
With these measures, the issue of heat inside the house (especially with a controlled mechanical ventilation system, where you don’t keep opening windows to let in warm air) becomes much less significant.
With these measures, the issue of heat inside the house (especially with a controlled mechanical ventilation system, where you don’t keep opening windows to let in warm air) becomes much less significant.
One more addition regarding nordanney.
Although it is only 10km (6 miles) away, in our small town it never gets as warm as in the neighboring large city, so buildings here do not heat up as much and can cool down somewhat again at night. Previously, we lived very rurally by a stream among many trees, where it was cool in the evenings even during high summer. A 10°C (18°F) difference compared to the city, both day and night, was not unusual in summer.
So, the microclimate should also be taken into account here, and it makes it difficult to draw conclusions from one building to another beyond personal habits.
Although it is only 10km (6 miles) away, in our small town it never gets as warm as in the neighboring large city, so buildings here do not heat up as much and can cool down somewhat again at night. Previously, we lived very rurally by a stream among many trees, where it was cool in the evenings even during high summer. A 10°C (18°F) difference compared to the city, both day and night, was not unusual in summer.
So, the microclimate should also be taken into account here, and it makes it difficult to draw conclusions from one building to another beyond personal habits.
Musketier schrieb:
One more addition regarding nordanney.
Although it’s only 10 km (6 miles) away, the small town where I live never gets as warm as the nearby big city, so the buildings here don’t heat up as much and can cool down again at night. Previously, we lived very rurally, by a creek among many trees, where it stayed cool in the evenings even in midsummer. A 10°C (18°F) difference compared to the city, both day and night, was not unusual in summer.
So, the microclimate should definitely be considered here, and it makes it difficult to draw conclusions about one building based on another’s performance, besides personal habits. Exactly, those are additional factors, along with personal ones such as individual sensitivity to heat. I know for myself that I feel very uncomfortable when it’s humid or when I have to stay or even sleep in an overheated room. Therefore, my decision was in favor of air conditioning, and I love simply knowing that it’s there. Today, it’s already warm enough that I probably would have run the AC lightly during the day if I had been there.
But as @nordanney already mentioned, the topic starts much earlier.
So, those interested should share more information about their homes and situations here.
Similar topics