Underfloor heating runs at 35 °C, existing radiators need 55 °C. That one number decides the configuration, its efficiency and the work involved. Answer four questions and we'll name it.
Setting range 20–80 °C · declared performance at 35 and 55 °C
Declared performance data
Setting range only — ask before you design around it
4 – 35.3 kW
Across the range: 4–16 kW monoblock, 6.5–24 kW split, up to 35.3 kW for pools
A+++
Seasonal space heating class for the Hamme monoblock line, average climate — declared at both 35 and 55 °C leaving water. Split units are A++ at 55 °C
R290 · natural refrigerant
Natural refrigerant in the Hamme monoblock line. Split and pool units use R32
−25 °C
Declared heating operating range to −25 °C. Output falls as it gets colder — confirm capacity at your design temperature
Figures declared at A7/W35 (air 7 °C, leaving water 35 °C) and A7/W55.
Every situation below maps to a configuration we can name today, for Europe. The last card is the one where a heat pump is the wrong answer — we'd rather you knew now.
New build, or a renovation deep enough that the floors are coming up anyway.
Hamme All-in-One · Hamme monoblock
A half-renovated house where the two floors want two different water temperatures.
Hamme + Control Box · All-in-One
The house is from the eighties or nineties, the radiators are fine, and you have no intention of lifting the floors.
Hamme monoblock · Hamme Hydro + Hydrobox
Full replacement doesn't fit the budget, or the radiators need more than 55 °C on the worst nights.
Hamme + Control Box
No garage, no utility room, nowhere to stand a cylinder next to a hydraulic module.
Hamme All-in-One 200 / 240 L
The cylinder was replaced recently and there is no reason to throw it away.
Hamme Hydro + Hamme Hydrobox
A large or poorly insulated house where one residential unit won't cover the load.
Sauer R32 · Hamme + Control Box
The only sensible place for the outdoor unit is at the other end of the property.
Sauer R32
Three situations where the answer is no, or not yet.
Nowhere outside to put the unit — an apartment or a protected facade leaves no compliant position for an R290 monoblock. A neighbour a few metres from the only mounting position, where 55–66 dB(A) of sound power at night is a real problem. Not enough electrical supply — a 16 kW single-phase unit draws up to 34.8 A, and there is no three-phase version below 10 kW.
Talk to us before spending anything
None of these is quite your house?
Everything refrigerant-related is sealed in the outdoor unit, so no refrigerant circuit has to be connected on site. Expansion vessel already inside (4.5 L up to 10 kW, 8 L above), water up to the full 20–80 °C setting range. 4–16 kW.
Indoor hydraulic unit, outdoor compressor unit, refrigerant line between them. Reaches 23.98 kW without cascading and suits long distances to the plant room. Water tops out at 60 °C, and the refrigerant is R32, not R290.
200 or 240 L cylinder, 3 kW immersion heater, 1+2 or 2+4 kW backup heater and an 8 L expansion vessel in one indoor tower. One supplier, one delivery. It stands 1780 mm tall (1985 mm for the 240 L version) and weighs 115–121 kg empty — measure the doorway.
A compact wall module with a 3-way valve and backup heater, connected to your own cylinder. The right answer when a good cylinder is already installed. Two things are on you: the expansion vessel, and the cylinder itself — BAUF does not sell a standalone tank.
The heat pump covers the whole load. One heating system instead of two. It needs the emitters to work at 55 °C or below, and it needs the electrical supply to carry the largest unit you might need.
The heat pump carries the base load, the existing boiler takes the peaks. The control box integrates an auxiliary heat source directly. Lower electrical demand, smaller unit, and a fallback on the worst night of the year — but you keep two systems and two service visits.
Where a heat pump does its best work: COP up to 5.50 at A7/W35 and a seasonal SCOP up to 5.20 at 35 °C. If you're building or stripping floors anyway, this is the version worth designing for.
Still works, and no floors come up. COP around 3.05–3.40 at A7/W55 — roughly a third less heat per unit of electricity than underfloor. Oversized radiators or a couple of replacements close much of that gap.
Still deciding between two of these?
| Product | What it is | Output | Refrigerant | |
|---|---|---|---|---|
 | Hamme | Monoblock with hydraulics and expansion vessel on board. No backup heater. | Output4–16 kW | RefrigerantR290 |
| Hamme Hydro | The same outdoor unit prepared for a separate indoor module. | Output4–16 kW | RefrigerantR290 |
 | Hamme Hydrobox | Indoor module with 3-way valve and 3 / 6 kW backup heater. Needs your cylinder. | Outputto 10 / to 16 kW | Refrigerant— |
 | Hamme All-in-One | Indoor tower with a 160, 200 or 240 L cylinder and a built-in backup heater. | Output10 / 16 kW | Refrigerant— |
 | Hamme Control Box | Cascade of up to 8 units over Modbus, dual-zone, bivalent boiler, pool, solar thermal, scheduling. | Output— | Refrigerant— |
 | Sauer | Split system: indoor hydraulic unit plus outdoor unit. Water to 60 °C. | Output6.46–23.98 kW | RefrigerantR32 |
 | SAAR P | Pool heat pump, full inverter, nine sizes. Pools from 6 to 126 m³. | Outputto 35.3 kW | RefrigerantR32 |
Full specifications, drawings and manuals live in the catalogue.
BAUF sells through installers and distributors, and they price the whole job, not the box. These are the six lines that decide what you'll be quoted.
Capacity class and configuration. All-in-One costs more than a bare monoblock and saves you buying a cylinder.
Buffer tank if the system volume is low, expansion vessel on hydrobox installs, safety group, filter, glycol.
A cylinder, unless it's built in or you already own one.
Breaker, RCD, cable run. A 16 kW single-phase unit draws up to 34.8 A — sometimes the supply itself has to be upgraded.
Nothing, if the radiators cope at 55 °C. A few replaced radiators, if they don't.
Mounting, drainage, pipework, commissioning. Installation must comply with local regulations and be carried out by a suitably qualified installer.
Only a seller can quote the whole job. We can tell you which one to ask.
Showroom, training centre and warehouse under one roof — spare parts held in Europe and installers trained on the equipment they fit.
As published in the 2026 catalogue for the monoblock range. Terms may vary by market.
Shown at Mostra Convegno Expocomfort, after C&R Madrid in 2025.
BAUF sells through installers and distributors and controls distribution, training and service. We don't sell direct — the finder ends with a seller near you.
Asked something we haven't answered here?
The four questions and the request form are on our climate site.
Pick your country and see the partners listed for it.
Send us the room count and what you're heating with now. That's usually enough for a first answer.
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