Corner Fireplace Insert with Cast Iron Door and Water Boiler Prity AC W20 – 5 kW + 20 kW Water

Cast Iron Front. Corner-Built. Whole-House Heat.

The Prity AC W20 brings together everything the Prity A range offers separately: the corner-mounted body that fills unused wall space, a cast iron door that holds and releases heat long after the flames have settled, and a 20 kW water heat exchanger that carries most of the fire's energy straight into your central heating system. 5 kW of radiant heat still warms the room it stands in directly.

Made in Bulgaria. EU Ecodesign compliant.

How Much Space Can It Heat?

Prity doesn't publish an official heated-area figure for the Prity AC W20, so this is our own estimate, based on the heated-area-to-power ratio observed across comparable Prity models in our range (roughly 7.5 m² per kW). Here, that ratio applies to the unit's combined output of 25 kW — 5 kW radiating into the room plus 20 kW into the water circuit, which spreads its heat through radiators installed around the house rather than from the insert itself. Combined, that puts the Prity AC W20 at approximately 185 m², depending on your home's insulation, radiator layout, and how the heating system is balanced.

Cast Iron: the Material That Outlasts Everything Else

The Prity AC W20's door is cast iron — the same dense, heavy material used in the best stoves for generations, chosen because it absorbs heat progressively during combustion and releases it back slowly. A ceramic glass panel set into the door keeps the fire visible at all times, kept clear by the secondary air wash system that runs fresh air across the inner surface during burning.

Corner Placement That Changes How a Room Heats

Positioning an insert in a corner isn't just a space-saving trick — it's a genuine heating strategy. A corner-mounted firebox radiates heat across a wide arc of the room rather than throwing it in a single direction from a flat wall, which means more even heat distribution, fewer cold spots, and a room that feels comfortable from more angles.

A Water Heat Exchanger Built for Central Heating

The Prity AC W20 delivers 20 kW to its water heat exchanger at nominal output, alongside 5 kW of direct radiant heat into the room. The water tank holds 34 litres, with a maximum working pressure of 1.25 bar and 1″ water connections for both flow and return.

This is a boiler-type appliance: it must be connected to a working central heating system before use, and should never be run dry or disconnected from your water circuit. Installation and commissioning by a qualified heating engineer is required.

Clean Combustion, Class A Efficiency

The Prity AC W20 achieves a combustion efficiency (η) of 78.3% and a seasonal space heating energy efficiency of 69%, with an energy efficiency index of 105 — placing it in energy class A. Emissions at nominal output: CO at 1167 mg/Nm³, particulate matter at 25 mg/Nm³, NOx at 93 mg/Nm³, and OGC at 17 mg/Nm³ — all within EU Ecodesign limits.

Fuel consumption at nominal output is 8.0 kg of dry wood per hour, reflecting the load of heating both the room and your water circuit. Flue gas temperature is 223°C, with a mass flow rate of 21.2 g/s.

A Firebox Built for Corner Installations

The combustion chamber measures 535 mm wide, 405 mm deep, and 350 mm high — sized to sustain the longer, hotter burns a boiler system needs to keep up with central heating demand, within a body shaped to sit comfortably in a room corner.

Important Installation Note

The Prity AC W20 uses a Ø200 mm flue outlet and requires a minimum chimney draught of 13.7 Pa. Please confirm your chimney connection is compatible with this diameter before ordering. Its corner geometry means installation requires careful planning of the surrounding hearth structure on both adjoining walls. At 131 kg, the unit needs a floor and framing capable of supporting the weight, and professional installation — including connection to your heating system — is required, not optional.

Overall dimensions: 660 × 630 × 880 mm (W × D × H).

30 Years of European Engineering Behind Every Weld

Prity has manufactured solid fuel heating appliances in Gorna Oryahovitsa, Bulgaria, since 1995. With more than 250 production staff and a range refined across three decades, the company builds inserts that earn their place in a home for years. Every unit is manufactured to the relevant EN standards and independently verified.

Your Prity AC W20 comes with a 24-month manufacturer's warranty.

Everything You Get

• 5 kW of direct radiant heat, plus 20 kW to your water heat exchanger (25 kW combined)

• Cast iron door with ceramic glass panel — superior heat retention and a classic aesthetic

• Corner-mounted design — fits neatly into any room corner, radiating heat across the whole space

• 34-litre water tank, 1.25 bar maximum working pressure, 1″ water connections

• Class A energy efficiency with a seasonal space heating energy efficiency of 69%

• Combustion efficiency (η) of 78.3%

• Firebox: 535 × 405 × 350 mm (W × D × H)

• Fuel consumption: 8.0 kg of dry wood per hour at nominal output

• Overall footprint: 660 × 630 mm

• Flue outlet: Ø200 mm — confirm chimney compatibility before ordering

• Net weight: 131 kg

• 24-month manufacturer's warranty

Box Contents

Insert body with cast iron door, ceramic glass panel, and integrated water heat exchanger, technical manual.

Use only dry, chemically untreated natural wood with a moisture content not exceeding 20%. Do not burn household waste, painted wood, plywood, or treated wood. This appliance must be connected by a qualified installer to a working central heating system before use — never operate it disconnected from your water circuit. Always consult a qualified installer before connecting the appliance to your chimney system, and before building the surrounding hearth structure for a corner installation. Note: this model requires a Ø200 mm flue connection and 1″ water connections.