ᐅ LWZ 8 CS Premium Combination Unit with Air-to-Water Heat Pump, Controlled Ventilation System, and Hot Water Storage Tank
Created on: 6 Jul 2020 20:56
B
Bauherr am LB
Bauherr am L6 Jul 2020 20:56Hello friends!
Originally, we were considering a ground-source heat pump because we thought that with an air-to-water heat pump we wouldn’t qualify for government subsidies.
However, during a discussion with our heating installer and a representative from Stiebel Eltron, we were told that we can meet the BAFA (Federal Office for Economic Affairs and Export Control) subsidy requirements even with an air-to-water heat pump, which would save us the significant extra costs for drilling.
We were now recommended the LWZ 8 CS Premium from Stiebel Eltron as a combined unit. Our heating load is 7.6 kW (calculated externally), so it would be suitable. What we like is that the LWZ 8 CS Premium does not require an outdoor unit.
Now my specific questions: In the conversation, the combined unit was strongly recommended. One argument was that the exhaust air from the integrated mechanical ventilation with heat recovery is also used for heating purposes, increasing energy efficiency. Additionally, everything is built into this one device, which supposedly reduces the installation effort and makes it easier for the technicians. From your point of view, is there any reason against choosing the combined unit?
The alternative would be three separate units (heat pump, whether ground-source or air-to-water / mechanical ventilation with heat recovery / hot water storage tank)...
Thanks
Originally, we were considering a ground-source heat pump because we thought that with an air-to-water heat pump we wouldn’t qualify for government subsidies.
However, during a discussion with our heating installer and a representative from Stiebel Eltron, we were told that we can meet the BAFA (Federal Office for Economic Affairs and Export Control) subsidy requirements even with an air-to-water heat pump, which would save us the significant extra costs for drilling.
We were now recommended the LWZ 8 CS Premium from Stiebel Eltron as a combined unit. Our heating load is 7.6 kW (calculated externally), so it would be suitable. What we like is that the LWZ 8 CS Premium does not require an outdoor unit.
Now my specific questions: In the conversation, the combined unit was strongly recommended. One argument was that the exhaust air from the integrated mechanical ventilation with heat recovery is also used for heating purposes, increasing energy efficiency. Additionally, everything is built into this one device, which supposedly reduces the installation effort and makes it easier for the technicians. From your point of view, is there any reason against choosing the combined unit?
The alternative would be three separate units (heat pump, whether ground-source or air-to-water / mechanical ventilation with heat recovery / hot water storage tank)...
Thanks
The exhaust air in a mechanical ventilation system with heat recovery (not directly integrated into the heat pump) is routed through a heat exchanger, which helps reduce heating costs.
An all-in-one unit might simplify installation for the heating technician, but it also means that your investment is tied to a single manufacturer.
Consider this: what happens if the heat pump fails? Can you still use the ventilation system, or do you have to replace everything even though only the heat pump is faulty?
What if you are not satisfied with the all-in-one solution and want to replace it after 15 years? These devices are often optimized for space, so when it’s time to switch brands or replace the system, you usually have to install another all-in-one unit because your technical room cannot accommodate anything else without a major redesign. This also creates customer dependency.
I would always recommend separate solutions—that is, a standalone heat pump combined with a separate mechanical ventilation system with heat recovery. There are manufacturers that offer both components if you want to avoid using different brands.
An all-in-one unit might simplify installation for the heating technician, but it also means that your investment is tied to a single manufacturer.
Consider this: what happens if the heat pump fails? Can you still use the ventilation system, or do you have to replace everything even though only the heat pump is faulty?
What if you are not satisfied with the all-in-one solution and want to replace it after 15 years? These devices are often optimized for space, so when it’s time to switch brands or replace the system, you usually have to install another all-in-one unit because your technical room cannot accommodate anything else without a major redesign. This also creates customer dependency.
I would always recommend separate solutions—that is, a standalone heat pump combined with a separate mechanical ventilation system with heat recovery. There are manufacturers that offer both components if you want to avoid using different brands.
I find the device much more attractive than the separate solutions. Installers don’t have to deal with the piping between the units (which is quite complex and expensive), and you also need less space.
I also don’t think it’s likely that the device will break down quickly. Stiebel Eltron is a market leader, the units are designed for very long service life, and the quality is good.
I also don’t think it’s likely that the device will break down quickly. Stiebel Eltron is a market leader, the units are designed for very long service life, and the quality is good.
Bauherr am L schrieb:
The alternative would be three separate units (heat pump, whether ground source or air source / controlled ventilation system / hot water storage tank)...Just have everything calculated for you. Choose whatever is more cost-effective. Whether you go for the combined unit or three separate ones is more a matter of preference.B
Bauherr am L7 Jul 2020 09:06Mycraft schrieb:
Just have everything calculated for you. You choose whichever option is cheaper. Whether you go for the integrated unit or three separate ones is more a matter of preference. All right, that’s a good idea. I thought there might be clear arguments, but opinions seem divided here as well.
I’ve read that it’s important to have a proper bypass in a mechanical ventilation system with heat recovery. However, I can’t find anything about this in the device description. Do modern mechanical ventilation systems with heat recovery all have such a bypass to allow cool air to enter the house at night in summer without heat recovery?
Bauherr am L schrieb:
Do controlled residential ventilation systems nowadays all have a bypass to bring cold air into the house at night during summer without heat recovery? No, of course not. It is an extra feature. Most systems include it "by default," but you never know what you might actually get.
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