{"id":1623,"date":"2014-09-10T11:36:07","date_gmt":"2014-09-10T09:36:07","guid":{"rendered":"https:\/\/hottubstock.com\/?post_type=product&p=1623"},"modified":"2026-08-08T08:34:16","modified_gmt":"2026-08-08T06:34:16","slug":"external-wood-fired-hot-tub-heater","status":"publish","type":"product","link":"https:\/\/www.woodenhottubsale.co.uk\/ie\/product\/external-wood-fired-hot-tub-heater\/","title":{"rendered":"TimberIN Nordic External\u2122 Wood-Fired Hot Tub Heater"},"content":{"rendered":"
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External wood heat in three output classes \u00b7 Purpose-built hot-tub heating<\/p>\n

TimberIN Nordic External\u2122 Wood-Fired Hot Tub Heater: preserve bathing space and service the fire from outside<\/h2>\n

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A separate stove gives the bathing area back to bathers<\/h2>\n

External placement is particularly useful when an internal heater would compromise seating or when the fire needs to be tended without entering the tub. Cooler water travels to the lower connection and heated water returns through the upper route in the approved arrangement. For naturally circulating systems, pipe diameter, length, rise and absence of air locks are critical. The stove also creates an equipment zone outside the tub that must remain clear for loading, ash removal and future inspection; hiding it tightly behind decorative cladding can undermine both safety and serviceability.<\/p>\n<\/section>\n

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Three outputs for three different thermal loads<\/h2>\n

Nordic External is a freestanding wood-fired hot-tub heater family. Moving from 22 to 28 or 40 kW is not simply paying for faster heat: output must remain compatible with water volume, connection area, natural or pumped circulation, fuel rate and the ability to control temperature. External placement keeps the tub interior free and makes the firebox accessible, while adding a second footprint, two water connections and a chimney zone beside the tub.<\/p>\n

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Selectable nominal outputs<\/th>\n22 kW, 28 kW or 40 kW<\/td>\n<\/tr>\n
Layout<\/th>\nFreestanding external wood-fired heater<\/td>\n<\/tr>\n
Tub compatibility<\/th>\nMust be confirmed from volume, shell material, port sizes, levels and circulation design<\/td>\n<\/tr>\n
Heat-up time<\/th>\nNot universal; calculate from water load and verify in commissioning<\/td>\n<\/tr>\n
Required site space<\/th>\nHeater body, firebox approach, connections, chimney and safe clearances<\/td>\n<\/tr>\n
Service advantage<\/th>\nAccessible without entering the bathing shell<\/td>\n<\/tr>\n
Installation effect<\/th>\nExtra footprint, exposed connections and more heat loss than a fully integrated route<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n

Open the product technical sheet<\/a><\/p>\n<\/section>\n

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How to decide between 22, 28 and 40 kW<\/h2>\n

The 22 kW model belongs with smaller or well-insulated water volumes where a calm firing rate is acceptable. The 28 kW version is the middle route for common family tubs. The 40 kW model may suit larger volumes or demanding recovery times, but only when the heat exchanger, water flow and chimney are designed for it. Oversizing can make temperature rise harder to control and increases fuel and clearance demands; undersizing extends the session. Supply the manufacturer with exact litres, port positions and intended winter use before choosing.<\/p>\n

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Decision<\/th>\nChoices currently selectable<\/th>\n<\/tr>\n<\/thead>\n
Power<\/th>\n22KW \u00b7 28KW \u00b7 40KW<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/section>\n
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Operational accessories: what each solves<\/h2>\n

An ash shovel makes routine cleaning cleaner and more controlled. A chimney guard reduces accidental contact where guests pass nearby. A glazed door lets the operator see flame condition without opening the firebox, but glass soots and needs cleaning. A thermometer and pressure valve add monitoring and protection only when installed in the approved location and system; they do not correct blocked circulation. Every accessory should remain reachable after decking and landscaping are complete.<\/p>\n

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Additional options<\/h3>\n
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  • Ash shovel<\/li>\n
  • Metal fence on the chimney (protection against burns)<\/li>\n
  • Heater's door with glass<\/li>\n
  • Thermometer and pressure valve<\/li>\n<\/ul>\n

    Advantages:<\/strong> The listed heater accessories improve firing control, ash handling, temperature awareness or separation from hot metal and should be matched to the exact stove and chimney supplied.<\/p>\n<\/section><\/div>\n<\/section>\n

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    Convert kilowatts into a planning range, not a promise<\/h2>\n

    Raising 2,000 litres by 30\u00b0C requires roughly 70 kWh before heat loss. At theoretical full transfer that is about 3.2 hours at 22 kW, 2.5 hours at 28 kW or 1.75 hours at 40 kW; a real wood installation takes longer because output varies and heat escapes. These figures are engineering context only. Dry fuel, cover, wind, pipe length, water flow and safe firing practice decide actual performance, which should be recorded during controlled commissioning.<\/p>\n<\/section>\n

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    Select output only after circulation and heat loss are understood<\/h2>\n

    Match 22, 28 or 40 kW to the supplier-approved tub volume, material and connection layout. Establish the shortest practical pipe route, support the pipework and avoid reductions or valves that could restrict flow unless the engineered design explicitly requires them. Plan a compliant chimney, heat shielding and clearance from timber, covers and planting. Heat-up time will still vary with starting water temperature, weather, fuel moisture, wind and cover quality, so compare the whole thermal system rather than choosing the largest rating on the assumption that it will solve every site issue.<\/p>\n<\/section>\n