Fireplace Insert with Water Boiler Prity M W18 – 5.1 kW + 18.4 kW Water

The Fire for the Room. The Heat for the Whole House.

The Prity M W18 takes the compact, steel-fronted body of the Prity M and builds a water heat exchanger into it: most of the energy from every fire goes directly into your central heating system, while 5.1 kW of radiant heat and the ceramic glass door still warm 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 M W18, 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 23.5 kW — 5.1 kW radiating into the room plus 18.4 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 M W18 at approximately 175 m², depending on your home's insulation, radiator layout, and how the heating system is balanced.

A Compact Body That Still Packs a Boiler

Despite its more compact 700 × 590 mm footprint, the Prity M W18 fits in a full water heat exchanger without sacrificing firebox capacity — the combustion chamber still measures a generous 575 × 490 × 360 mm. The ceramic glass door is kept clear by the secondary air wash system, which runs a continuous curtain of fresh air across the inner glass surface during burning.

A Water Heat Exchanger Built for Central Heating

The Prity M W18 delivers 18.4 kW to its water heat exchanger at nominal output, alongside 5.1 kW of direct radiant heat into the room. The water tank holds 37 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 M W18 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 7.3 kg of dry wood per hour, reflecting the added 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.

Important Installation Note

The Prity M W18 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. At 121 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: 700 × 590 × 710 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 M W18 comes with a 24-month manufacturer's warranty.

Everything You Get

• 5.1 kW of direct radiant heat, plus 18.4 kW to your water heat exchanger (23.5 kW combined)

• Large ceramic glass door — clear view of the fire, kept clean by the secondary air wash system

• 37-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: 575 × 490 × 360 mm (W × D × H)

• Fuel consumption: 7.3 kg of dry wood per hour at nominal output

• Overall footprint: 700 × 590 mm

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

• Net weight: 121 kg

• 24-month manufacturer's warranty

Box Contents

Insert body with ceramic glass door 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. Note: this model requires a Ø200 mm flue connection and 1″ water connections.