Three-Sided Fireplace Insert with Water Boiler Prity 3C W35 – 5 kW + 35 kW Water

An Open View of the Fire. Serious Heat for a Larger Home.

The Prity 3C W35 is the larger-capacity sibling of the 3C W28, built around the same panoramic three-sided glazing but stepping up to a 35 kW water heat exchanger and a larger 60-litre tank — suited to bigger homes or heating systems with a heavier central heating load. 5 kW of radiant heat and an open view of the flame from the front and both sides still warm the room it sits in directly.

Built in Bulgaria. EU Ecodesign compliant.

How Much Space Can It Heat?

Prity doesn't publish an official heated-area figure for the 3C W35, so this is our own estimate, based on the heating-area-to-output ratio across comparable Prity models in our range (roughly 7.5 m² per kW). Here, that ratio applies to the appliance's combined output of 40 kW — 5 kW radiant into the room plus 35 kW into the water circuit, which radiates its heat through radiators installed around the house rather than from the insert itself. Combined, that puts the 3C W35 at approximately 300 m², depending on your home's insulation, radiator layout, and how the heating system is balanced.

Glass on Three Sides: An Open View of the Fire

Like the 3C and 3C W28, this insert is glazed on the front and both sides, giving an almost uninterrupted view of the fire from multiple angles in the room — well suited to open, freestanding-style installations rather than a wall-flush setup.

A Larger Water Heat Exchanger for Bigger Homes

The 3C W35 delivers 35 kW to its water heat exchanger at nominal output, alongside 5 kW of direct radiant heat into the room. The water tank holds 60 litres — double the 3C W28 — with a maximum working pressure of 1.25 bar and 1″ water connections for both the flow and return.

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

Clean Combustion, Class A Efficiency

The 3C W35 reaches a combustion efficiency (η) of 78.6% and a seasonal space heating energy efficiency of 70%, with an energy efficiency index of 105 — placing it in energy class A. Emissions at nominal output: CO at 1,208 mg/Nm³, particulate matter at 30 mg/Nm³, NOx at 96 mg/Nm³, and OGC at 21 mg/Nm³ — all within EU Ecodesign limits.

Fuel consumption at nominal power is 12.7 kg of dry wood per hour, reflecting the larger heat exchanger's demand. Flue gas temperature is 258°C, with a mass flow of 25.3 g/s.

A Wide, Deep Firebox

The 3C W35's firebox measures 660 mm wide, 595 mm deep, and 370 mm tall — sized to sustain the longer, hotter burns a larger boiler system needs, while still making full use of the three-sided glazing.

Important Installation Note

The 3C W35 uses a Ø200 mm flue outlet and requires a minimum chimney draught of 12.2 Pa. Please confirm your chimney connection is compatible with this diameter before ordering. Because the firebox is glazed on three sides, installation requires careful planning of the surrounding structure and hearth on all exposed faces. At 254 kg, this is one of the heaviest inserts in our range — 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 footprint: 800 × 730 × 1140 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 many years. Every unit is manufactured to relevant EN standards and independently verified.

Your 3C W35 ships with a 24-month manufacturer warranty.

Everything You Get

• 5 kW of direct radiant heat, plus 35 kW to your water heat exchanger (40 kW combined)

• Three-sided glazing — front, left, and right, for an open view of the fire

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

• Energy efficiency class A, with a seasonal heating efficiency of 70%

• Combustion efficiency (η) of 78.6%

• Wide firebox: 660 × 595 × 370 mm (W × D × H)

• Overall dimensions: 800 × 730 × 1140 mm (W × D × H)

• Fuel consumption: 12.7 kg of dry wood per hour at nominal output

• Flue outlet: Ø200 mm — minimum chimney draught of 12.2 Pa required

• Net weight: 254 kg

• 24-month manufacturer warranty

Box Contents

Insert body with integrated water heat exchanger, heat-resistant glazing on three sides, 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 to a functioning central heating system by a qualified installer 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 structure for a three-sided installation. Note: this model requires a Ø200 mm flue connection and 1″ water connections.