Kitchen Extraction for London Victorian Terraces: Range Hoods, Ducted vs Recirculating, and Part F Compliance

APPROVED DOCUMENT PART F 2021 (MEANS OF VENTILATION — ENGLAND — THE BUILDING REGULATIONS 2010 — PART F1 — VENTILATION FOR DWELLINGS) REQUIRES KITCHEN SPACES IN A DWELLING TO BE PROVIDED WITH A MINIMUM LEVEL OF EXTRACT VENTILATION TO REMOVE MOISTURE AND POLLUTANTS FROM COOKING — WITH SPECIFIC MINIMUM AIRFLOW RATES DEPENDING ON WHETHER THE VENTILATION IS PROVIDED BY A COOKER HOOD/EXTRACTOR OR BY GENERAL KITCHEN VENTILATION.

PART F 2021 — EXTRACT VENTILATION IN A KITCHEN: MINIMUM EXTRACT RATE FOR A KITCHEN (WHERE THE COOKER IS ADJACENT TO AN EXTERNAL WALL OR DUCT AND CAN BE DUCTED TO OUTSIDE — DUCTED EXTRACTION): 30 L/S (LITRES PER SECOND — EQUIVALENT TO 108 M³/HOUR) ADJACENT TO THE HOB — THIS IS THE MINIMUM BOOST RATE THAT THE EXTRACTION SYSTEM MUST ACHIEVE — IT DOES NOT MEAN 30 L/S CONTINUOUS BACKGROUND VENTILATION — IT MEANS THE EXTRACTION SYSTEM MUST BE CAPABLE OF EXTRACTING AT LEAST 30 L/S AT ITS BOOST SETTING WHEN IN USE FOR COOKING. CONTINUOUS BACKGROUND VENTILATION (FOR THE KITCHEN AS PART OF THE WHOLE DWELLING VENTILATION SYSTEM UNDER PART F): A MINIMUM CONTINUOUS BACKGROUND VENTILATION RATE OF 13 L/S IS REQUIRED FOR THE KITCHEN (AS PART OF THE WHOLE DWELLING TRICKLE VENTILATION OR DECENTRALISED MECHANICAL EXTRACT VENTILATION (DMEV) SYSTEM — SEE VENTILATION GUIDE). NOTE: 30 L/S IS THE REGULATORY MINIMUM — IN PRACTICE, MOST PROFESSIONAL KITCHEN DESIGNERS SPECIFY A SIGNIFICANTLY HIGHER EXTRACTION RATE TO ADEQUATELY CAPTURE ALL COOKING VAPOUR AT THE HOB: BRITISH STANDARD BS EN 61591:2015 (DOMESTIC COOLING HOODS — PERFORMANCE TESTING FOR COOKING HOOD/RANGE HOOD PERFORMANCE) SPECIFIES A GUIDANCE EFFECTIVE EXTRACTION RATE OF APPROXIMATELY 400-600 M³/HOUR (110-165 L/S) FOR A 90CM WIDE HOB — A FAR HIGHER RATE THAN THE PART F MINIMUM. PART F 2021 DOES NOT SPECIFY A REQUIREMENT FOR RECIRCULATING (NON-DUCTED) EXTRACT IN A KITCHEN — HOWEVER IT DOES ALLOW RECIRCULATING SYSTEMS WHERE DUCTING TO OUTSIDE IS NOT PRACTICABLE, PROVIDED THAT ADEQUATE BACKGROUND VENTILATION (TRICKLE VENTS, OPEN WINDOWS) IS AVAILABLE TO MANAGE THE RESIDUAL MOISTURE THAT RECIRCULATING FILTRATION DOES NOT REMOVE.

THE CHOICE BETWEEN DUCTED EXTRACTION (AIR IS CARRIED VIA A DUCT — TYPICALLY 150MM OR 200MM ROUND DUCT OR EQUIVALENT FLAT RECTANGULAR DUCT — FROM THE EXTRACTOR HOOD TO AN OUTSIDE GRILLE ON THE REAR OR SIDE WALL OF THE PROPERTY, OR THROUGH THE FLAT ROOF OF A REAR EXTENSION) AND RECIRCULATING EXTRACTION (AIR IS PASSED THROUGH GREASE FILTERS AND ACTIVATED CHARCOAL FILTERS AND RETURNED TO THE KITCHEN SPACE) IS THE SINGLE MOST IMPORTANT TECHNICAL DECISION IN KITCHEN EXTRACTION SPECIFICATION.

DUCTED EXTRACTION (STRONGLY PREFERRED FOR ALL SERIOUS KITCHEN SPECIFICATION — PART F MINIMUM DUCTED EXTRACTION RATE 30 L/S / 108 M³/HOUR — TYPICAL SPECIFIED RATE 400-700 M³/HOUR FOR OPEN-PLAN KITCHEN): ADVANTAGES: (1) REMOVES MOISTURE, GREASE, ODOURS, AND COMBUSTION PRODUCTS COMPLETELY FROM THE KITCHEN AIR — RECIRCULATING DOES NOT REMOVE MOISTURE — MOISTURE MUST BE REMOVED TO PREVENT CONDENSATION ON WALLS AND WINDOWS IN A VICTORIAN TERRACE (WHICH IS ALREADY PRONE TO CONDENSATION DUE TO SOLID BRICK WALLS AND POOR ORIGINAL VENTILATION); (2) PERFORMANCE: DUCTED EXTRACTION USING A 150MM OR 200MM ROUND DUCT (MINIMUM RECOMMENDED DIAMETER — 100MM DUCT IS TOO SMALL FOR A HIGH-PERFORMANCE HOOD AND CREATES EXCESSIVE NOISE AND BACK PRESSURE) CAN ACHIEVE 500-1000 M³/HOUR EXTRACTION RATE — FAR HIGHER THAN ANY RECIRCULATING SYSTEM; (3) NOISE: DUCTED EXTRACTION IS GENERALLY QUIETER THAN RECIRCULATING — THE MOTOR WORKS LESS HARD AGAINST A CLEAR AIR PATH COMPARED TO THE BACK PRESSURE OF RECIRCULATING FILTERS. RECIRCULATING EXTRACTION (USED WHERE DUCTING TO OUTSIDE IS NOT PRACTICABLE — LISTED BUILDING/CONSERVATION AREA EXTERIOR CANNOT BE PENETRATED — OR WHERE DUCT ROUTING IS EXCESSIVELY LONG OR COMPLEX): DISADVANTAGES: DOES NOT REMOVE MOISTURE — RESIDUAL MOISTURE RETURNS TO THE KITCHEN AIR AFTER CHARCOAL FILTRATION — IN A VICTORIAN TERRACE WITH SOLID WALLS AND POOR BACKGROUND VENTILATION, THIS CAN CAUSE CONDENSATION PROBLEMS; CHARCOAL FILTERS REQUIRE REPLACEMENT EVERY 3-6 MONTHS (DEPENDING ON COOKING INTENSITY) AT A COST OF £30-80 PER SET — RECIRCULATING IS NOT MAINTENANCE-FREE; ODOUR REMOVAL IS LESS COMPLETE THAN DUCTED; EXTRACTION RATE IS TYPICALLY LIMITED TO 200-400 M³/HOUR IN RECIRCULATING MODE (LOWER THAN DUCTED — DUE TO FILTER BACK PRESSURE).

THE MARKET FOR KITCHEN EXTRACTION HOODS AND SYSTEMS IS DIVIDED BETWEEN SEVERAL MAIN PRODUCT TYPES — EACH WITH DIFFERENT INSTALLATION REQUIREMENTS, DUCT ROUTING OPTIONS, AND PERFORMANCE CHARACTERISTICS.

CANOPY HOOD (THE MOST COMMON EXTRACTION SYSTEM IN UK RESIDENTIAL KITCHEN RENOVATION — A STAINLESS STEEL, GLASS, OR CHIMNEY-STYLE CANOPY FIXED UNDER OR INSIDE A CABINET ABOVE THE HOB — CONNECTED TO A 150MM OR 200MM ROUND OR FLAT RECTANGULAR DUCT THAT ROUTES TO THE EXTERIOR): NEFF D95IMW5N0B (NEFF — BSH HOME APPLIANCES — 90CM — 750 M³/HOUR DUCTED — FLAT GLASS CANOPY — TOUCH CONTROL — DISHWASHER-SAFE GREASE FILTER — PART OF NEFF HOME CONNECT CONNECTED HOME SYSTEM — THE MOST FREQUENTLY SPECIFIED MID-TO-HIGH END EXTRACTION HOOD IN LONDON RESIDENTIAL KITCHEN RENOVATION IN THE 2020S — TYPICALLY SPECIFIED WITH NEFF INDUCTION HOB NEFF T66PHX4L0 OR SIMILAR NEFF HOB): SIEMENS LC91BBM50B (SIEMENS HOME — BSH HOME APPLIANCES — 90CM — 755 M³/HOUR DUCTED — CHIMNEY HOOD — SIMILAR SPEC TO NEFF — SIEMENS AND NEFF ARE SISTER BRANDS OF BSH — BOTH MANUFACTURED AT THE SAME BSH PLANTS); AEG DVB5960HB (AEG/ELECTROLUX — 90CM CHIMNEY HOOD — 695 M³/HOUR DUCTED — TOUCHSCREEN — DISHWASHER-SAFE GREASE FILTER). CEILING EXTRACTOR (ISLAND EXTRACTOR — A CEILING-MOUNTED EXTRACTION UNIT SUSPENDED ABOVE A KITCHEN ISLAND — REQUIRES THE DUCT TO BE ROUTED THROUGH THE CEILING VOID AND ABOVE — SUITABLE WHERE THE HOB IS ON AN ISLAND AND A WALL-MOUNTED HOOD IS NOT POSSIBLE): ELICA NIKOLATESLA FLAT (ELICA S.P.A — FABRIANO, ITALY — THE LEADING PREMIUM CEILING EXTRACTOR BRAND IN THE UK HIGH-END RESIDENTIAL KITCHEN MARKET — NIKOLATESLA FLAT = FLUSH-MOUNTED FLAT CEILING EXTRACTOR — INTEGRATED INTO THE CEILING — INVISIBLE WHEN NOT IN USE — 600MM X 600MM OR 900MM X 900MM VERSIONS — 700 M³/HOUR DUCTED). DOWNDRAFT EXTRACTOR (RISES FROM BELOW OR BEHIND THE HOB LEVEL WHEN IN USE — DUCTED THROUGH THE WORKTOP OR FLOOR): BORA PURE (BORA GMBH & CO KG — RAUBLING, BAVARIA — THE PREMIUM DOWNDRAFT HOB EXTRACTOR BRAND — BORA PURE COMBINES A GLASS CERAMIC HOB WITH AN INTEGRATED EXTRACTOR THAT DRAWS AIR DOWN THROUGH THE HOB SURFACE ITSELF — 700 M³/HOUR MAX DUCTED — VERY UNUSUAL DUCT ROUTING: THROUGH THE WORKTOP SURFACE, THEN THROUGH THE KITCHEN UNIT CARCASS, THEN BELOW THE FLOOR OR THROUGH THE WALL — REQUIRES SPECIALIST INSTALLATION).

THE ROUTING OF THE EXTRACTION DUCT FROM THE KITCHEN HOOD TO THE EXTERNAL GRILLE IS ONE OF THE MOST PRACTICALLY COMPLEX ASPECTS OF KITCHEN EXTRACTION IN A LONDON VICTORIAN TERRACE — PARTICULARLY WHERE THE KITCHEN HAS BEEN RELOCATED TO A NEW REAR EXTENSION, OPEN-PLAN LAYOUT, OR KITCHEN-DINER EXTENDING TO THE FULL REAR WALL.

MINIMUM DUCT DIAMETER: 150MM ROUND DUCT (SPIRODUCT GALVANISED STEEL OR EQUIVALENT — PRIMADUCT, SPIRALITE, FLEXIBLE ALUMINIUM DUCT SUCH AS DANTHERM OR RENSON RIDGIDUCT) — 150MM IS THE MINIMUM FOR A 90CM HOOD AT 500-700 M³/HOUR — USE 200MM DUCT WHERE THE RUN IS LONGER THAN 2-3M OR WHERE THERE ARE MORE THAN 2 BENDS. MAXIMUM DUCT RUN LENGTH: PER BS 5440-2:2000 (INSTALLATION OF FLUES AND VENTILATION) AND KITCHEN HOOD MANUFACTURER INSTALLATION REQUIREMENTS — THE EFFECTIVE DUCT LENGTH (STRAIGHT RUN + BEND ALLOWANCES) SHOULD NOT EXCEED 3-5M FOR A 150MM DUCT — EACH 90° BEND ADDS AN EQUIVALENT STRAIGHT LENGTH OF APPROXIMATELY 1.0-1.5M; EACH 45° BEND APPROXIMATELY 0.5-0.8M. EXTERNAL GRILLE: STANDARD PLASTIC PUSH-FIT WALL GRILLE (NOT ADEQUATE FOR HIGH-PERFORMANCE EXTRACTION — CAUSES BACK PRESSURE AND NOISE): SPECIFY INSTEAD A LOW-RESISTANCE GRAVITY BACK-DRAUGHT SHUTTER GRILLE (MANROSE CF100G OR EQUIVALENT — GRAVITY-FLY LOUVRE OPENS UNDER POSITIVE AIRFLOW, CLOSES BY GRAVITY WHEN EXTRACTOR IS OFF — PREVENTS COLD AIR BACK-FLOW AND BIRD ENTRY). WALL PENETRATION (REAR ELEVATION OF VICTORIAN TERRACE — BRICK): DIAMOND CORE DRILL 162MM (FOR 150MM DUCT) OR 212MM (FOR 200MM DUCT) — CUTTING THROUGH 215MM VICTORIAN BRICK WALL — TYPICALLY REQUIRES A DIAMOND CORE DRILL HIRE OR SPECIALIST DRILLING CONTRACTOR — NOT A HAMMER DRILL AND SDS BIT. FLAT ROOF PENETRATION (REAR EXTENSION FLAT ROOF — THE MOST COMMON ROUTE IN A CONTEMPORARY KITCHEN EXTENSION): CORE DRILL THROUGH ROOF DECK (IF STRUCTURAL CONCRETE) OR JIGSAW CUT THROUGH OSB/PLY DECK — WEATHER-TIGHT ROOF PENETRATION USING A DURAFLEX ROUND PIPE ROOF PENETRATION (SARNAFIL-COMPATIBLE) OR FLATROOF DUCT TERMINAL — CRITICALLY: THE ROOF PENETRATION MUST BE FULLY WEATHERPROOFED — A SARNAFIL WELDED OR EPDM FLASHED DUCT COLLAR — NOT JUST SEALANT AROUND THE DUCT — ANY LEAK AT THIS POINT WILL CAUSE INTERNAL WATER INGRESS INTO THE KITCHEN CEILING.

KITCHEN EXTRACTION COSTS (LONDON 2025 — ELECTRICAL/KITCHEN FIT CONTRACTOR — SUPPLY AND FIT — LABOUR AND MATERIALS).

STANDARD CANOPY HOOD (NEFF D95IMW5N0B OR EQUIVALENT SIEMENS/AEG — 90CM — DUCTED — 150MM DUCT THROUGH REAR WALL — UP TO 2M DUCT RUN — INCLUDING DUCT, DIAMOND CORE DRILL, EXTERNAL GRILLE, ELECTRICAL CONNECTION): NEFF D95IMW5N0B HOOD SUPPLY COST: APPROXIMATELY £400-600 (TRADE PRICE FROM AO.COM, EURONICS, JOHN LEWIS) + INSTALLATION LABOUR: £300-600 FOR STANDARD DUCTED INSTALLATION (DUCT THROUGH REAR WALL, UP TO 2M) = TOTAL APPROXIMATELY £700-1,200; COMPLEX DUCT RUN (THROUGH FLAT ROOF, 4-5M DUCT RUN WITH 2-3 BENDS, WEATHERTIGHT ROOF PENETRATION): ADD £300-600 TO THE ABOVE. PREMIUM CEILING EXTRACTOR — ISLAND (ELICA NIKOLATESLA FLAT OR EQUIVALENT — 90X90CM — FLUSH CEILING MOUNTED — DUCTED THROUGH CEILING VOID AND ROOF — SPECIALIST INSTALLATION): HOOD SUPPLY: APPROXIMATELY £1,500-3,500 + INSTALLATION: £600-1,200 (CEILING VOID DUCT ROUTING, ROOF PENETRATION, PLASTERBOARD INFILL AROUND HOOD) = TOTAL APPROXIMATELY £2,100-4,700. BORA PURE OR EQUIVALENT DOWNDRAFT HOB+EXTRACTOR (SUPPLY AND FIT — INTEGRATED DOWNDRAFT HOB — SPECIALIST INSTALLATION — DUCT THROUGH FLOOR/BELOW UNIT): SUPPLY: £2,000-4,500 + INSTALLATION: £800-1,500 (SPECIALIST DUCT ROUTING THROUGH FLOOR) = TOTAL APPROXIMATELY £2,800-6,000. RECIRCULATING HOOD (ELICA BLADE OR EQUIVALENT 90CM — NO DUCT — CHARCOAL FILTERS — SUPPLY AND FIT): £300-800 ALL-IN INCLUDING ELECTRICAL CONNECTION (LOW INSTALLATION COST VS DUCTED — NO CORE DRILL OR DUCT ROUTING — BUT ONGOING CHARCOAL FILTER REPLACEMENT COST: £30-80 EVERY 3-6 MONTHS).