Vaillant aroTHERM pro 11kW: What It Is and Why It's Worth Considering

The aroTHERM pro range just grew. Vaillant launched the 5 kW and 7 kW pro models earlier this year, and has now added an 11 kW version, taking the range from a fit for flats and well-insulated new builds to a fit for most UK homes.

If you've read our aroTHERM pro vs plus comparison, you already know why the pro line has an edge: the Flexible Space Function, a smaller footprint, a lower price, and a better-looking finish. The 11 kW carries all of that into a size bracket that used to mean choosing Vaillant's bulkier, twin-fan plus instead.

What's new with the 11 kW

With the plus, once your home needs more than 7 kW, you jump straight to a 10 kW unit, and past that to 12 kW. Both are twin-fan. Two fans need more room to move the same air, so that's a bigger box to site.

The 11 kW pro sits across that whole middle band on a single fan. A home that would previously have needed the jump from a 10 kW to a 12 kW plus can often stay on the smaller, single-fan pro instead, in the same compact casing style as the 5 kW and 7 kW models.

aroTHERM pro 11kW at a glance

The benefits it inherits from the rest of the range

Flexible Space Function

R290 is flammable, so R290 heat pumps need a clear exclusion zone around the outdoor unit, normally one metre in every direction, free of sockets, light switches, and openable windows or doors. Activate FSF and the unit's fan runs continuously at low speed. That constant airflow disperses any leaked refrigerant before it can build up, which is the actual risk the exclusion zone rules exist to guard against. Because the risk is managed actively instead of just by keeping the area clear, the zone shrinks from one metre on every side to just the area directly below the unit. That's what lets the 11 kW go into corners, side returns, and spots tight against a wall or fence that a fixed one-metre exclusion zone would rule out. The current-generation plus has the same feature, so it isn't unique to the pro, but it's still what makes the 11 kW workable on tight plots. It costs an estimated 25 kWh a year in extra running cost, and it's activated in the commissioning wizard.

A single fan instead of two

At 133 kg and 1,169 mm wide, the 11 kW keeps the compact, single-fan casing style of the 5 kW and 7 kW models rather than the larger twin-fan casing the plus needs at 10 kW and 12 kW.

A lower price than the equivalent plus

The exact difference depends on merchant and timing, but the pro consistently comes in below the plus at a comparable size.

A longer warranty than it looks like on paper

Vaillant's out-of-the-box guarantee is 2 years. Installed and registered through Heat Geek, that extends to 5 years.

Everything else the pro range brought

sensoCOMFORT control with the myVAILLANT app, a variable-speed circulation pump, and eligibility for the £7,500 Boiler Upgrade Scheme grant.

Why 11 kW specifically

The 11 kW is rated for 7.43 kW of nominal output at A7/W35 with a CoP of 5.22, but that nominal figure understates what it can actually deliver in a UK winter. At a 0°C design temperature with a 35°C flow, Vaillant's own planning data puts it at 12.65 kW. That's real headroom for larger detached and semi-detached homes, older properties with higher heat loss, and family homes with heavier hot water demand.

It also supports flow temperatures up to 65°C, which matters if you're retrofitting a home with older radiators you don't want to upsize one by one. And because the compressor and refrigerant circuit are built for it, the same unit can add active cooling later, rated up to 12.95 kW at A35/W18.

None of that comes at the cost of what made the smaller pro models good options in the first place. It's still a single fan. It still gets Flexible Space Function. Going up in output doesn't force a compromise on where it goes.

Where the pro still isn't the right call

If your heat loss assessment comes out above what the 11 kW can cover, or your flow temperature requirements sit outside its range, the plus's 12 kW (or a cascade of units) is still the right answer. And if a long UK installation track record matters more to you than the newer features, the plus has been out for years and the 11 kW pro is still new to market.

Is the aroTHERM pro 11 kW right for your home?

Heat Geek installs the full aroTHERM pro range, 5 kW through 11 kW, and we've been fitting the 11 kW since it reached general availability in June. If your heat loss assessment would previously have pointed you to a plus 10 kW or 12 kW, put the 11 kW pro at the top of the list first: same Flexible Space Function, same lower price, and a single fan instead of the plus's two. The thing to actually check is whether your heat loss falls within its range, which is exactly what a Heat Geek Design Consultation is for.