ᐅ Air-to-Water Heat Pump: Choosing Between Viessmann and Ochsner
Created on: 31 Jan 2023 18:13
N
NilsHolgersson
Hello dear community,
we have two air-to-water heat pump offers for our semi-detached house:
1. Viessmann Vitocal 200-S 201.E10 with 7.4 kW
2. Ochsner Air Hawk 208 C11A
The most important factors are trouble-free operation and reasonable service.
Key data about the house:
Do you have any experience with either of these? I could only find rather negative reports about the Vitocal.
The installation company mainly works with Viessmann systems and recommends it specifically, but they can also install the Ochsner unit.
Thanks a lot!
Best regards
we have two air-to-water heat pump offers for our semi-detached house:
1. Viessmann Vitocal 200-S 201.E10 with 7.4 kW
2. Ochsner Air Hawk 208 C11A
The most important factors are trouble-free operation and reasonable service.
Key data about the house:
- Semi-detached house, built with solid construction, not a KfW-certified house (roughly equivalent to a KfW-60 standard)
- Two full floors plus basement, ground floor + upper floor 68 + 68 sqm (732 + 732 sq ft), plus about 30 sqm (323 sq ft) of heated basement area
- Underfloor heating, controlled ventilation system with heat recovery and enthalpy heat exchanger
- No photovoltaic system installed primarily
Do you have any experience with either of these? I could only find rather negative reports about the Vitocal.
The installation company mainly works with Viessmann systems and recommends it specifically, but they can also install the Ochsner unit.
Thanks a lot!
Best regards
D
Daniel-Sp2 Feb 2023 09:49NilsHolgersson schrieb:
The heating load calculation is still pending, but roughly estimated: the new building according to the 2016 Energy Saving Ordinance has a heating demand closer to 0.05 kW/sqm, about 165 sqm (1776 sqft) of heated floor area: 0.05 x 165 = 8.25 kW. The pump from Viessmann has 7.4 kW. Why is it considered oversized? Just trying to understand 🙂 Well, that’s a bit of a guess...
With my guess, I would have assumed more like 35 watts/sqm.
K
KarstenausNRW2 Feb 2023 17:13NilsHolgersson schrieb:
the new building according to the 2016 Energy Saving Ordinance The 2016 Energy Saving Ordinance was already obsolete in 2020.
NilsHolgersson schrieb:
Semi-detached house, built with solid construction, not a KfW-certified house (approximately “KfW-60”) By 2023, at least KfW55 standards with stricter requirements apply. You also have a semi-detached house, which usually has a lower energy demand than a detached single-family home (the thermal connection to the neighboring semi-detached house is great since there’s no window that could worsen your energy calculations).
In addition, a heat pump is more likely to be undersized than oversized. And you have a mechanical ventilation system with heat recovery.
I’d bet my life on the fact that a 5 kW heat pump is totally sufficient for you. I would definitely not install such a large heat pump. To my knowledge, these units cannot modulate below 4 kW, so at moderate outdoor temperatures like now, they basically run at full capacity and don’t know where to put the excess heat.
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