Who We Are ?

J SONS & CO. designs and installs ventilation systems across London and all over the UK. Mechanical Ventilation with Heat Recovery (MVHR), mechanical extract systems, kitchen extract canopies, toilet and washroom exhaust, smoke ventilation, positive input ventilation and full commercial ductwork in London. 

Our London engineers work to Building Regulations Part F (Approved Document F 2022), CIBSE TM52 and the BSRIA Air Tightness and Ventilation Test Standard. 

Why Ventilation Matters?

Ventilation is the most underrated building service in commercial and residential construction. Heating gets attention because cold buildings are uncomfortable. Cooling gets attention because warm offices are unproductive. Ventilation gets attention only when something goes wrong, such as condensation, mould, sick building syndrome, kitchen smoke leaks, restaurant complaints, or building control rejection at completion.

The cost of getting ventilation right at the design stage is a small fraction of the cost of getting it wrong. Three real outcomes from inadequate ventilation that we see regularly:

Condensation and mould: modern airtight construction without adequate background ventilation produces interstitial condensation within months. Once mould takes hold, remediation costs typically exceed the original ventilation system cost by 5–10×.

Building control rejection at handover: Part F (UK)  require commissioned ventilation test results at completion. Failure to meet airflow rates means the building cannot be signed off. Refits on completed projects are expensive.

Indoor Air Quality complaints: sick building syndrome, employee absenteeism, retail customer complaints, and hotel guest complaints. All trace back to inadequate fresh air supply, recirculated stale air, or contaminated filtration.

J SONS & CO. designs ventilation to meet the regulatory minimum and the performance the building actually needs. These are not always the same thing.

Types of Ventilation Systems We Install

Mechanical Ventilation with Heat Recovery (MVHR)

MVHR systems extract stale, moist air from kitchens, bathrooms and utility rooms (“wet rooms”) and supply fresh, filtered air to bedrooms, living rooms and other habitable spaces. A counter-flow heat exchanger transfers up to 92% of the heat from the outgoing air to the incoming air, meaning the system delivers fresh air without heat loss.

The default whole-dwelling ventilation strategy (System 3 under Part F) for airtight new-build housing, modern apartments, and refurbished period properties where airtightness has been improved. Also widely specified in offices, schools, healthcare and commercial spaces under Part F Volume 2.

Preferred manufacturers: Vent-Axia, Domus, Zehnder, Brink, Vaillant recoVAIR, Mitsubishi Lossnay, BPC Ventilation, Greenwood.

Mechanical Extract Ventilation (MEV)

A continuously-running centralised extract system serving multiple wet rooms through ducted extract grilles to a single fan unit. Lower capital cost than MVHR (no heat recovery), suitable where heat recovery is not required or where retrofit constraints make MVHR impractical.

Often specified in refurbishment projects, social housing renewals and properties where MVHR cannot be retrofit-fitted. Compliant with Part F System 2.

Decentralised Mechanical Ventilation (dMEV / dMVHR)

Individual single-room ventilation units are installed through external walls. Each wet room has its own continuously-running unit, kitchen, bathroom, and utility. dMEV without heat recovery is cheaper; dMVHR with single-room heat recovery is more energy-efficient.

Best suited to flats, conversions, listed buildings, and refurbishments where running centralised ductwork is not practical.

Positive Input Ventilation (PIV)

A single loft- or ceiling-mounted unit that introduces filtered air at low pressure into a dwelling, pushing stale air out through trickle vents, window frames and natural gaps. Used in older properties suffering from condensation where full MVHR is not practical. Lower installation cost, simpler to retrofit.

Intermittent and Continuous Extract Fans

Bathroom and kitchen extract fans, humidity-controlled, PIR-controlled, timed, or constantly-running low-flow. Compliant with Part F System 1 in the london, plumbing and ventilation regulations in the Harrow. Brand selection is driven by noise rating (dB(A)), airflow (l/s or m³/h) and aesthetic.

Preferred manufacturers: Vent-Axia, Manrose, Xpelair, Greenwood, Envirovent, Airflow, Soler & Palau, Systemair.

Air Handling Units (AHU)

Larger central air handlers connected to district cooling or building chilled water networks, conditioning and delivering air to multiple zones across high-rise commercial and residential buildings. 

Kitchen Extract Systems

Commercial kitchen ventilation, extract canopies, ductwork, in-line fans, grease filtration, ecology units (UV-C and ozone), make-up air units, and fire suppression interfaces. Designed and installed to:

UK: DW/172 BESA standard, Part F, kitchen ventilation, safe handover documentation, gas safety interlocks.

Light-touch single-canopy restaurants up to multi-zone hotel central kitchens with ecology units and roof-mounted ducted exhaust.

Toilet and Washroom Exhaust Systems

Dedicated ducted exhaust from toilet cubicles, washrooms and shower rooms. Constant or PIR-triggered. Negative pressure relative to adjacent spaces to prevent odour migration. Compliant with Part F minimum extract rates (UK).

Smoke Ventilation and Pressurisation Systems

Stair-pressurisation, lobby-pressurisation, corridor extract, atrium smoke clearance, and basement smoke ventilation. Critical fire-safety infrastructure in any building over 11m in the london.

UK: BS EN 12101 series, Approved Document B fire safety, smoke ventilation control panels.

Ductwork Design, Fabrication and Installation

Galvanised sheet metal ductwork to DW/144 london . Spiral, rectangular, semi-rigid and flexible ductwork. Acoustic insulation, fire dampers (BS 476-20 / UL listed), volume control dampers, balancing dampers, attenuators, grilles, diffusers and air valves.

In both cities, our ductwork installations are leak-tested to DW/143 air leakage classes A, B or C as specified, with commissioning certificates issued at handover.

Our Installation Process

Every ventilation project, a 5-bedroom MVHR retrofit in Hampstead , follows the same six-step process.

1. Free site survey and design intent review. Building drawings reviewed, site walk completed, Mechanical and Electrical (M&E) coordination documented. Existing ductwork (if any) condition-surveyed.
2. Design and calculations. Air change rates calculated per room type to Part F in london. System sizing, duct route design, equipment selection, noise calculation, and electrical loading.
3. Fixed-price quotation. Itemised: equipment, ductwork, insulation, dampers, controls, electrical work, commissioning, certification, warranty.
4. Programme and RAMS. Programme of works, fire risk method statement (for ducting works in occupied buildings), permit-to-work processes (for confined spaces, working at height, hot works on ductwork).
5. Fabrication and installation. Ductwork fabricated to drawings, off-site spiral and rectangular, on-site connections. Equipment installed, ducted, insulated, dampers fitted, controls wired.
6. Commissioning, testing and certification. Airflow is measured at every grille and balanced to design figures. Leak testing on ductwork. Noise testing. Filter installation. Controls programmed. Building Regulations compliance certificate london. Full O&M manual and asset register handed over.

Ventilation Installation in London

UK Regulatory Framework: Building Regulations Part F

Part F is the single most important regulation governing ventilation in the UK. Updated in June 2022 as part of the Future Homes and Buildings Standard, it sets four ventilation system options:

For any new-build dwelling or significant refurbishment, the choice is almost always System 3 or System 4, driven by the property’s airtightness (measured at air pressure test) and the energy strategy.

Approved Document F Volume 1 covers domestic ventilation. Volume 2 covers non-domestic buildings, offices, retail, schools, and healthcare. Both volumes set minimum extract rates per wet room, minimum air supply rates per occupant, and minimum air change rates for specific room types.

Other UK Standards That Apply

• CIBSE TM52 / TM59, Overheating risk assessment for residential and non-domestic buildings.
• BS 5720, Code of practice for mechanical ventilation in buildings.
• DW/144 HVCA ductwork specification for sheet metal ductwork.
• DW/143  Ductwork air leakage testing standard (Classes A, B, C).
• DW/172  BESA standard for commercial kitchen ventilation.
• BS EN 12101  Smoke and heat control systems.
• Approved Document B: Fire safety, including smoke ventilation requirements.
• CIBSE TM44  Air conditioning energy assessments (affects ventilation in mixed systems).

London Ventilation Installation Costs

Indicative pricing. Fixed-price quote after free site survey. VAT additional.

London Service Coverage

All 32 London boroughs and the City of London, Central London, Canary Wharf, Mayfair, Soho, Shoreditch, Holborn, King’s Cross, Camden, Westminster, Kensington, Chelsea, Hammersmith, Fulham, Battersea, Vauxhall, Wandsworth, Clapham, Greenwich, Stratford, Wembley, Croydon, Bromley, Romford. M25 corridor on request: Watford, St Albans, Slough, Reading, Guildford, Sevenoaks, Dartford.

Ventilation Brands We Install

MVHR / MEV (UK): Vent-Axia, Domus, Zehnder, Brink, Vaillant recoVAIR, Mitsubishi Lossnay, BPC Ventilation, Greenwood, Nuaire, Titon, Aereco.

Extract fans : Vent-Axia, Manrose, Xpelair, Greenwood, Envirovent, Airflow, Soler & Palau, Systemair, Helios.

Kitchen extract: Halton, Britannia Living, Caple, Halton, Captive-Aire, NorPole.

Fire-rated smoke fans: Systemair, Soler & Palau, Casals, Flakt Group, Howden.

Ecology units / UV-C: Halton M.A.R.V.E.L., Captive-Aire ecology, Esco-Pure, Plasma Air.

Filters: Camfil, AAF (American Air Filter), Filtration Group, MANN+HUMMEL.

Controls and BMS interface: Trend, Cylon, Distech, Honeywell, Siemens, Belimo (damper actuation).

Sectors We Install Ventilation For

Offices, co-working spaces, corporate HQs, hotels, boutique hotels, serviced apartments, restaurants, cafés, dark kitchens, central production kitchens, supermarkets, retail units, shopping malls, schools, nurseries, universities, hospitals, healthcare clinics, dental practices, GP surgeries, veterinary surgeries, care homes, gyms, leisure centres, spas, hair and beauty salons, warehouses, distribution centres, food production facilities, data rooms, server rooms, places of worship, listed and heritage buildings, embassies, residential apartments, villas, high-rise residential towers, basement carparks and plant rooms.

Why Commercial and Residential Clients Choose J SONS & CO.

Design-led approach. Every project starts with proper air change calculations and equipment selection, not pulled off a previous job’s spec.

Ductwork to DW/144 / SMACNA standards. Off-site fabrication, where the programme requires it, on-site for retrofit projects. Leak-tested to the specified DW/143 class.

Kitchen extract specialism. From single-canopy restaurants to multi-canopy hotel central kitchens, with full ANSUL/Amerex fire suppression integration in DW/172 compliance in London.

Commissioning as a deliverable, not an afterthought. Every grille is balanced. Every duct is leak-tested. Every fan speed recorded against design. Documented and handed over.

No subcontracting on core ductwork. Ductwork fabrication and installation in-house. Quality, programme and accountability stay with us.

One contractor for multi-system projects. HVAC + ventilation + heating + controls one quote, one programme, one warranty.

Frequently Asked Questions

What are Building Regulations Part F?

Part F is the section of the UK Building Regulations governing ventilation. It sets minimum extract rates from wet rooms, minimum air supply rates per occupant, and minimum whole-dwelling ventilation rates depending on the building’s airtightness. Approved Document F (updated June 2022) sets four ventilation system options, Systems 1, 2, 3, and 4, covering everything from basic extract fans to full MVHR.

When do I need MVHR vs MEV?

MVHR (System 4) is required or strongly recommended for airtight new-build and certified low-energy properties; it recovers up to 92% of the heat from extracted air. MEV (System 3) is suitable for less airtight properties and refurbishments where retrofitting MVHR ductwork is impractical. Air pressure test results from the design stage determine which system the building actually needs.

What does an MVHR system cost in London?

A 1-bed flat MVHR installation typically costs £3,500–£6,500. A 3-bed house £5,500–£9,500. A 4–5 bed house £8,500–£14,500. Commercial MVHR for small offices £12,000–£28,000. Pricing is fixed after a free site survey.

Do you handle commercial kitchen ventilation?

Yes, both single-canopy restaurant installations and multi-canopy hotel central kitchens. In London, we install DW/172 BESA standard with gas safety interlocks. 

Do you install smoke ventilation systems?

Yes, stair pressurisation, lobby pressurisation, atrium smoke clearance, basement smoke ventilation, and corridor extract. In London, to BS EN 12101 series and Approved Document B.

Is ductwork cleaning included in maintenance?

Standard PPM does not include duct cleaning because it is needed every 18–24 months rather than every visit. It is quoted separately when inspection at a PPM visit shows it is due, typically £6–£18/m in London.

Can MVHR be retrofitted into an existing house?

Yes, in most cases. Semi-rigid ducted MVHR systems are designed specifically for retrofit and can be routed through ceiling voids, joist voids and bulkheads. Costs are higher than new-build MVHR (where ductwork goes in pre-plaster), but it is viable for most properties. We carry out a feasibility survey before quoting.

Do you commission systems installed by other contractors?

Yes. We carry out independent commissioning and Part F compliance certification for MVHR, MEV and commercial ventilation systems installed by others. This is useful for self-build clients, developers, or when the original installer is no longer available. Costs from £450 for residential MVHR commissioning in London.

Request a Ventilation System Quote

For London projects

Phone: +44 20 8050 7969 London

Email: info@jsonsco.com

Address: Wembley, London, United Kingdom, HA9.