Hello everyone,
for our new single-family house (about 170sqm (1830 sq ft), brine-to-water heat pump for heating and domestic hot water), we are getting a Viessmann system. Viessmann offers the Natural Cooling Box (NC-Box) as an add-on (around 4000 euros including installation and additional thermostats), which allows cool water to circulate through the underfloor heating in summer (cooled down passively via a plate heat exchanger with the brine). I understand that the cooling capacity is limited by the dew point (and there will be no ceiling cooling). Generally, I hear that the indoor temperature difference is about 3°C (5°F) with or without cooling.
I also realize that temperature perception varies, but nevertheless: Can anyone share first-hand experience with this or a similar system? Is the cooling effect noticeable during summer? How is the electricity consumption? Does the control system work properly?
Furthermore, I read somewhere here in the forum that the NC-Box ALWAYS consumes electricity – even when cooling, for example in winter, is turned off. That can’t be right, can it? Is this nonsense? Maybe a bit of electronics run at 0.25W, but the pump would at least be off, right?
Thanks in advance for any insights!
for our new single-family house (about 170sqm (1830 sq ft), brine-to-water heat pump for heating and domestic hot water), we are getting a Viessmann system. Viessmann offers the Natural Cooling Box (NC-Box) as an add-on (around 4000 euros including installation and additional thermostats), which allows cool water to circulate through the underfloor heating in summer (cooled down passively via a plate heat exchanger with the brine). I understand that the cooling capacity is limited by the dew point (and there will be no ceiling cooling). Generally, I hear that the indoor temperature difference is about 3°C (5°F) with or without cooling.
I also realize that temperature perception varies, but nevertheless: Can anyone share first-hand experience with this or a similar system? Is the cooling effect noticeable during summer? How is the electricity consumption? Does the control system work properly?
Furthermore, I read somewhere here in the forum that the NC-Box ALWAYS consumes electricity – even when cooling, for example in winter, is turned off. That can’t be right, can it? Is this nonsense? Maybe a bit of electronics run at 0.25W, but the pump would at least be off, right?
Thanks in advance for any insights!
Hi,
I also use an active heat pump system for cooling through the underfloor heating. Active, because I only have an air-source heat pump.
- The cooling effect is around 2-3°C (4-5°F). That’s quite noticeable when it’s really hot outside, and the floors feel correspondingly cool. We don’t mind it.
- The power consumption in natural cooling mode is lower compared to active cooling. It’s roughly around 200W. After all, the pumps still have to run.
- If you want better cooling performance, a concrete core activation system would be recommended (not to be confused with ceiling heating). This can significantly improve the cooling effect compared to underfloor heating. The costs are manageable. The benefits include
Unfortunately, I can’t provide any information about the standby power consumption of natural cooling with Viessmann.
Best regards,
Nika
I also use an active heat pump system for cooling through the underfloor heating. Active, because I only have an air-source heat pump.
- The cooling effect is around 2-3°C (4-5°F). That’s quite noticeable when it’s really hot outside, and the floors feel correspondingly cool. We don’t mind it.
- The power consumption in natural cooling mode is lower compared to active cooling. It’s roughly around 200W. After all, the pumps still have to run.
- If you want better cooling performance, a concrete core activation system would be recommended (not to be confused with ceiling heating). This can significantly improve the cooling effect compared to underfloor heating. The costs are manageable. The benefits include
- higher comfort,
- pre-cooled air if controlled residential ventilation ducts are installed in the ceiling,
- and last but not least, more energy-efficient heating, as the supply temperature can be significantly reduced.
Unfortunately, I can’t provide any information about the standby power consumption of natural cooling with Viessmann.
Best regards,
Nika
Since we are also planning the costs for a house and I definitely want some form of cooling, the question of costs is currently open for me.
The house will have a ground floor plus upper floor, and air conditioning was planned for the living room on the ground floor, the home office, and once upstairs in the bedroom. Now, after learning about it, concrete core activation sounds interesting to me.
In total, the ground floor will be about 90m² (including walls, etc.) or 150m² of living space (ground floor plus upper floor).
- For example, if a decentralized ventilation system is standard, it seems you first need to pay the extra cost for a central ventilation system. Unfortunately, I have no idea about the price range for this in a house of this size.
- Then there might be an additional cost for an air-to-water heat pump as opposed to a ground-source heat pump (from what I have read, drilling costs are around 10,000€ (about $11,000), otherwise the prices are roughly the same?).
- And then there is the concrete core activation—what cost might that roughly add?
Would concrete core activation work with an air-to-water heat pump if a ground-source heat pump is not possible or too expensive, or would that not make sense?
So far, I have read that with a ground-source heat pump you can get BAFA funding, which covers about 35% of costs for all heating-related systems. If possible, that would almost offset the additional costs of the ground-source heat pump. With an air-to-water heat pump, you reach the required 4.5 "something" (too many abbreviations and values in too short a time; probably an efficiency value, but either not or only with devices that are supposedly not very good).
Would a combination of an air-to-water heat pump (or better, a ground-source heat pump), central ventilation, and concrete core activation be a sensible alternative to a split-system air conditioner? (Considering both initial and long-term costs).
The house will have a ground floor plus upper floor, and air conditioning was planned for the living room on the ground floor, the home office, and once upstairs in the bedroom. Now, after learning about it, concrete core activation sounds interesting to me.
In total, the ground floor will be about 90m² (including walls, etc.) or 150m² of living space (ground floor plus upper floor).
- For example, if a decentralized ventilation system is standard, it seems you first need to pay the extra cost for a central ventilation system. Unfortunately, I have no idea about the price range for this in a house of this size.
- Then there might be an additional cost for an air-to-water heat pump as opposed to a ground-source heat pump (from what I have read, drilling costs are around 10,000€ (about $11,000), otherwise the prices are roughly the same?).
- And then there is the concrete core activation—what cost might that roughly add?
Would concrete core activation work with an air-to-water heat pump if a ground-source heat pump is not possible or too expensive, or would that not make sense?
So far, I have read that with a ground-source heat pump you can get BAFA funding, which covers about 35% of costs for all heating-related systems. If possible, that would almost offset the additional costs of the ground-source heat pump. With an air-to-water heat pump, you reach the required 4.5 "something" (too many abbreviations and values in too short a time; probably an efficiency value, but either not or only with devices that are supposedly not very good).
Would a combination of an air-to-water heat pump (or better, a ground-source heat pump), central ventilation, and concrete core activation be a sensible alternative to a split-system air conditioner? (Considering both initial and long-term costs).
Teemoe86 schrieb:
- For example, if only a decentralized ventilation system is installed as standard, you probably have to pay extra for a central ventilation system. Unfortunately, I don’t have an estimate of the cost for this house size. You can easily calculate it yourself. Living area × ceiling height × desired air exchange rate → e.g. 130sqm × 2.5m × 0.4 = 130 cubic meters per hour.
However, I always consider 0.4 too low. That’s just enough to prevent mold. I would estimate a 3 to 5 times air exchange rate. That way you have enough fresh air in the house when needed (parties, odors, airing out, or even cooling by ventilation). Just be careful, especially if you don’t install it yourself, that the ventilation installer (which in single-family houses is often the plumber, and the principle “he didn’t know what he had” unfortunately applies quite often) does not design the outlet air velocities too high. It’s better to have several outlets instead.
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