Mechanical Ventilation in London Homes: MVHR, dMEV and PIV Systems 2025

MVHR IS THE WHOLE-HOUSE VENTILATION SOLUTION OF CHOICE FOR HIGH-PERFORMANCE LONDON RENOVATION PROJECTS AND NEW-BUILD LONDON HOMES IN 2025. AN MVHR SYSTEM CONTINUOUSLY EXTRACTS STALE, HUMID AIR FROM WET ROOMS (KITCHEN, BATHROOMS, UTILITY) AND SIMULTANEOUSLY SUPPLIES FRESH, FILTERED AIR TO LIVING AND SLEEPING ROOMS — RECOVERING 85-95% OF THE HEAT FROM THE OUTGOING AIR BEFORE EXHAUSTING IT. KEY MVHR PRODUCTS SPECIFIED IN LONDON IN 2025: ZEHNDER COMFOAIR Q350 — THE MOST SPECIFIED PREMIUM MVHR UNIT IN LONDON RESIDENTIAL AND PASSIVHAUS PROJECTS; EFFICIENCY 93%, NOISE LEVEL 23 DB(A) AT LOW SPEED; INTEGRAL SUMMER BYPASS; AVAILABLE FROM ZEHNDER UK (COVENTRY). VENT-AXIA SENTINEL KINETIC PLUS — THE MOST WIDELY INSTALLED MVHR UNIT IN LONDON RESIDENTIAL RENOVATION AT MID-RANGE PRICE POINT; 89% EFFICIENCY; COMPACT BOX UNIT SUITABLE FOR SMALLER LONDON LOFT AND CUPBOARD PLANT SPACES; AVAILABLE FROM VENT-AXIA DISTRIBUTORS ACROSS LONDON. TITON HRV1.5 Q PLUS MVHR — A FURTHER UK-MANUFACTURED ALTERNATIVE; 85% EFFICIENCY; POPULAR IN LONDON NEW-BUILD PROJECTS MANAGED BY LONDON PRINCIPAL CONTRACTORS. DUCTWORK — MVHR REQUIRES A DUCT DISTRIBUTION SYSTEM (RADIAL LOW-PRESSURE DUCTWORK USING VENTILAITON PRODUCTS UK VP RADIAL SYSTEM, OR SEMI-RIGID 75MM DUCT TO ALL ROOMS); IN LONDON RETROFIT PROJECTS, DUCT RUNS ARE TYPICALLY CONCEALED IN NEW CEILING VOID, ROOF SPACE OR FLOOR VOID.

DECENTRALISED MECHANICAL EXTRACT VENTILATION (DMEV) PROVIDES CONTINUOUS LOW-RATE EXTRACT VENTILATION FROM INDIVIDUAL ROOMS WITHOUT THE NEED FOR A CENTRAL UNIT OR DUCTWORK DISTRIBUTION. EACH UNIT IS INSTALLED THROUGH THE EXTERNAL WALL OR WINDOW OF THE ROOM IT SERVES. KEY DMEV PRODUCTS FOR LONDON IN 2025: VENT-AXIA LO-CARBON TEMPRA — THE MOST INSTALLED DMEV PRODUCT IN LONDON BATHROOM AND KITCHEN EXTRACT VENTILATION UPGRADES; IT RUNS CONTINUOUSLY AT LOW SPEED (6-8 L/S AT TRICKLE RATE) AND BOOSTS TO 22 L/S WHEN TRIGGERED BY HUMIDITY SENSOR; THROUGH-THE-WALL INSTALLATION; MEETS BUILDING REGULATIONS PART F ADE CONTINUOUSLY RUNNING EXTRACT REQUIREMENTS. NUAIRE CYFAN — THE NUAIRE CYFAN IS A DMEV UNIT WIDELY USED IN SOCIAL HOUSING AND PRIVATE SECTOR LONDON BATHROOM VENTILATION; RUNS AT 6L/S CONTINUOUS. TITON TRIMVENT XCITE 4000 — A COMPACT DMEV UNIT TYPICALLY USED IN LONDON FLAT CONVERSIONS WHERE WALL THICKNESS IS LIMITED; THROUGH-WINDOW OR THROUGH-WALL INSTALLATION. RAVEN AIRMASTER — THROUGH-THE-WALL DMEV FOR LONDON PROPERTIES WHERE EXTERNAL WALL DEPTH ALLOWS; POPULAR IN LONDON HOUSING ASSOCIATION RETROFIT PROJECTS. DMEV IS A COST-EFFECTIVE PART F COMPLIANCE SOLUTION FOR LONDON BATHROOM AND KITCHEN VENTILATION UPGRADES IN EXISTING PROPERTIES WHERE MVHR IS NOT PRACTICAL.

POSITIVE INPUT VENTILATION (PIV) IS THE MOST COST-EFFECTIVE WHOLE-HOUSE VENTILATION SOLUTION FOR EXISTING LONDON PROPERTIES WHERE DAMP, CONDENSATION AND MOULD ARE A RECURRING PROBLEM BUT MVHR INSTALLATION IS NOT PRACTICAL OR AFFORDABLE. A PIV UNIT DRAWS FRESH AIR FROM THE LOFT SPACE (WHERE IT IS DRIER AND LESS CONTAMINATED THAN INDOOR AIR), CONDITIONS IT SLIGHTLY (SOME UNITS INCLUDE A SMALL HEATING ELEMENT TO AVOID COLD DRAUGHTS), AND SUPPLIES IT INTO THE HALL OR LANDING AT LOW VELOCITY — GENTLY PRESSURISING THE HOUSE SO STALE, HUMID AIR IS DISPLACED THROUGH NATURAL LEAKAGE PATHS. KEY PIV PRODUCTS IN LONDON IN 2025: VENT-AXIA POZIDRY PRO PIV — THE MOST INSTALLED PIV UNIT IN LONDON PRIVATE SECTOR HOUSING; MOUNTS IN THE LOFT, SUPPLY UNIT GOES IN THE HALLWAY CEILING; ENERGY CONSUMPTION 12-17W; INCLUDES BUILT-IN HEATER FOR WINTER CONDITIONS. NUAIRE DRIMASTER ECO HC — THE NUAIRE DMEV AND PIV RANGE IS WIDELY USED IN LONDON SOCIAL HOUSING AND HOUSING ASSOCIATION STOCK; THE DRIMASTER ECO HC IS A LEADING PIV UNIT FOR LONDON HOUSES AND FLATS.

BUILDING REGULATIONS PART F (MEANS OF VENTILATION) APPLIES TO ALL LONDON BUILDING REGULATIONS WORK INVOLVING ROOMS THAT REQUIRE VENTILATION. THE KEY REQUIREMENTS FOR LONDON RESIDENTIAL PROPERTIES: BACKGROUND VENTILATION — ALL HABITABLE ROOMS IN LONDON PROPERTIES MUST HAVE BACKGROUND VENTILATION (4000MM² EQUIVALENT AREA PER ROOM) — THIS IS TYPICALLY PROVIDED BY TRICKLE VENTS IN WINDOW FRAMES (RAVEN, AIRMASTER, GIESSE TRICKLE VENTS IN WINDOW FRAMES); WHERE WINDOWS ARE REPLACED IN LONDON WITH SEALED UNITS, TRICKLE VENTS MUST BE RETAINED OR A MECHANICAL ALTERNATIVE PROVIDED. EXTRACT VENTILATION — KITCHENS AND BATHROOMS/EN-SUITES MUST HAVE EXTRACT VENTILATION AT A MINIMUM RATE OF 30 L/S (KITCHENS) OR 15 L/S (BATHROOMS) INTERMITTENTLY, OR 6-8 L/S CONTINUOUSLY. THIS IS MET BY A DMEV, MVHR OR INTERMITTENT FAN WITH HUMIDITY SENSOR AND OVERRUN TIMER. WHOLE-DWELLING VENTILATION RATE — FOR PART F COMPLIANCE, THE WHOLE DWELLING BACKGROUND VENTILATION RATE MUST BE SUFFICIENT FOR THE OCCUPANCY; MVHR OR PIV SYSTEMS ARE USED TO MEET THIS IN AIR-TIGHT LONDON RENOVATION PROJECTS.

MECHANICAL VENTILATION SYSTEM COSTS IN LONDON IN 2025: DMEV (SINGLE VENT-AXIA LO-CARBON TEMPRA UNIT, SUPPLY AND INSTALL, THROUGH-WALL CORE DRILL IN LONDON TERRACE, WIRING BY LONDON ELECTRICIAN) — £200-£400 PER ROOM; TYPICAL LONDON BATHROOM DMEV — £200-£350; PIV SYSTEM (VENT-AXIA POZIDRY PRO PIV OR NUAIRE DRIMASTER, SUPPLY AND INSTALL IN LONDON TERRACE INCLUDING LOFT INSTALLATION AND HALLWAY UNIT) — £600-£1,200 FULLY INSTALLED; MVHR (ZEHNDER COMFOAIR Q350 OR VENT-AXIA SENTINEL KINETIC PLUS, FULL HOUSE SYSTEM WITH DUCTWORK TO ALL ROOMS, SUPPLY AND INSTALL IN A 3-BED LONDON SEMI-DETACHED OR TERRACE AS PART OF A MAJOR RENOVATION) — £5,000-£12,000; MVHR IN A LONDON NEW-BUILD (PART OF NEW BUILD PROGRAMME, DUCTWORK IN CEILING VOIDS) — £3,000-£7,000.