High-efficiency air source heat pumps: A+++ air-to-water units up to 75 °C
An air-to-water heat pump takes energy from the outside air and transfers it to the water for heating, underfloor cooling and domestic hot water. In this collection Q-Tech brings together the Viessmann and Domusa Teknik heat pumps it sells today, for homes and commercial use, and integrates them into your plant room or delivers them inside a pre-assembled plant room.
How to choose between Viessmann and Domusa Teknik
Q-Tech has selected the brands in this collection on technical criteria and for the good results obtained in our installations. Q-Tech is a Viessmann Lead PRO Partner.
We suggest Viessmann if you want advanced control with self-diagnostics and error codes, the ViCare and One Base ecosystem or commercial outputs. We suggest Domusa Teknik if you are looking for good value for money or have no room for an outdoor unit.
| Data | Viessmann | Domusa Teknik |
|---|---|---|
| Maximum flow temperature | 58 to 75 °C depending on model | 60 to 75 °C depending on model |
| Refrigerant | R290 (natural) or R32 depending on model | R290 (natural) or R32 depending on model |
| Built-in DHW cylinder | From 190 l depending on model | 135 l on the NanoClima 4 HDX 135 |
Summary for information purposes only, prepared by Q-Tech in October 2026 from the technical data sheets each manufacturer publishes and from our installation experience, to help you get your bearings among the brands we sell. It is general and indicative: manufacturers update their data and a summary may contain errors, so each product page and the manufacturer's documentation always prevail, without prejudice to your rights as a consumer (Legal Notice). It is common for customers to change their mind once they know each brand's strengths, or to find that a feature they liked is not essential in their case.
A heat pump runs for many years in your home, and a choice that does not fit your installation shows up in running costs and in wear on the unit. If you want to decide with the data of your own case, you can book our professional technical advice (a paid service): an Expert Technician reviews the features of your home and installation with you and guides you with Q-Tech's experience, under an obligation of means (Legal Notice).
Models in this collection
| Model | Type | Heating output (A7 W35) | Maximum flow temperature |
|---|---|---|---|
| Viessmann | |||
| Vitocal 200-A ie | R290 monobloc with indoor unit | 2.8 to 5.4 kW | 75 °C |
| Vitocal 150-A, Compact and Modular | R290 monobloc; Compact with 190 l DHW; Modular in cascade | 4.0 to 9.1 kW | 70 °C |
| Vitocal 250-A PRO | R290 monobloc for commercial use | 21.5 kW rated (range 8 to 39.5 kW) | 70 °C |
| Vitocal 100-S and 111-S | R32 split; 111-S with DHW cylinder | 4.1 to 8.1 kW | 58 °C |
| Vitocal 262-A and 060-A | Hot-water-only heat pumps | Hot water only | DHW up to 62 or 65 °C on heat pump alone |
| Domusa Teknik | |||
| Dual Clima HT Pro and HT EC Pro | R290 monobloc; EC version with Easy Connect module sold separately | 6.2 to 22.7 kW | 75 °C |
| Dual Clima R and R EC | R32 monobloc; EC version with Easy Connect module sold separately | 6.1 to 18.1 kW | 60 °C |
| NanoClima 4 and 4 HDX 135 | Indoor R290, no outdoor unit; HDX with 135 l DHW | 4.0 kW | 75 °C |
Data from each manufacturer; Viessmann data from its domestic price list, September 2026. Each brand has all its models and its selection guide in Viessmann heat pumps and Domusa Teknik heat pumps, and its accessories in Viessmann accessories and Domusa accessories.
Applications
- Replacing a boiler while keeping the radiators, with 70 to 75 °C units.
- New builds with underfloor heating and cooling plus domestic hot water.
- Flats with no room for an outdoor unit, with the NanoClima, and commercial premises or buildings, with the Vitocal 250-A PRO or units in cascade.
Why choose Q-Tech for your heat pump?
- The heat pump arrives inside a pre-assembled plant room, tested in our workshop and ready to connect: see Advanced Pre-Assembly.
- If another company installs it, we first carry out a verification visit with the on-site hourly Expert Technician, followed by the pre-commissioning check.
- For availability, lead times and reservations, message us on WhatsApp.
Frequently asked questions
Can I keep my radiators?
In many cases, yes, with a high-temperature unit: the Vitocal 200-A ie, the Dual Clima HT Pro and the NanoClima reach 75 °C and the Vitocal 150-A 70 °C, according to their manufacturers. It is worth checking the home's heating demand and the radiator surface first.
What is the delivery time?
Each product page shows the availability of its unit. For very heavy units, transport is quoted separately.
Choose your brand and model with these data and leave the integration to Q-Tech: a pre-assembled plant room arrives tested and ready to connect.
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