Who We Are?

J SONS & CO. provides planned preventative maintenance (PPM) contracts and annual maintenance contracts (AMC) for commercial and residential air conditioning systems across London and Harrow or all over the UK. Quarterly servicing, half-yearly servicing, annual servicing, matched to the system type, operating hours, climate exposure and the regulatory regime that applies.

Our London engineers are F-Gas certified, REFCOM Elite registered, and NICEIC approved. Every PPM visit is documented with the F-Gas leak check record and refrigerant log that auditors, insurers and the HSE expect to see. 

Why Air Conditioning Maintenance Matters

A £25,000 commercial AC system has roughly the same maintenance economics as a £25,000 car. Drive it for fifteen years without an oil change, and the engine fails at year four. Service it twice a year, and the engine is still working at year fifteen.

Three things happen to an unmaintained AC system, in order:

Year one: efficiency drops silently. Filters clog. Coils foul with dust, grease and pollen. Refrigerant charge drops by 5–10% from microleaks. The system still cools but draws more power. The energy bill is 10–20% higher than it should be, and no one notices because there is no obvious fault.

Years two to three: components start to fail. Condensate drains block and trigger water damage. Fan motors run hot and seize. Capacitors fail. The first emergency call-out arrives, usually on the hottest day of the year. Each emergency repair costs roughly 5–8× what a service visit costs.

Years four to five: the system is replaced ten years early. Compressors fail. Refrigerant leaks become irreparable. The system is retired at year ten instead of year twenty. The avoidable replacement cost on a commercial install is typically £15,000–£60,000 in London.

A maintenance contract is the insurance policy that prevents this entire cascade. Industry data, confirmed by our own takeover surveys, shows that £1 invested in PPM saves £5–£8 in reactive repair costs.  What Is Included in a J SONS & CO. Service Visit

Every PPM visit at J SONS CO. follows a written, check listed procedure, the same procedure whether the engineer is in London. This is not a casual filter wipe. A full commercial AC service takes 45–90 minutes per unit and produces a written condition report.

Standard Inspection (Every Visit)

1. Filter inspection, clean or replacement: Pleated filters cleaned and reused where serviceable, replaced where degraded. Filter condition photographed for the service record.
2. Indoor coil inspection: Visual inspection for fouling, fin damage, biological growth, and condensate path obstruction.
3. Outdoor coil inspection: Visual inspection for fouling, fin damage, dust loading, and corrosion. Critical in London, where condenser fouling drives the largest single efficiency loss in the system.
4. Condensate drainage check: Drain pan inspected for biofilm and sludge, drain line flushed clear, condensate pump tested (where fitted).
5. Refrigerant pressure verification: High-side and low-side pressures measured against the manufacturer’s chart for the ambient temperature at the time of test. Deviation flagged.
6. Electrical inspection: Isolator tested, supply cable visually inspected, terminal torque check on incoming connections, contactors inspected for pitting, and capacitor microfarad value tested where accessible.
7. Fan motor and bearing check: Indoor and outdoor fan motors checked for noise, vibration, current draw against rated value, and bearing condition.
8. Thermostat and controller verification: Setpoint accuracy, sensor calibration, remote control function, BMS integration check, where applicable.
9. Performance test: System run under load. Supply air temperature measured at the grille, return air temperature measured at the intake, and temperature differential compared to specification.
10. Written condition report: Photographed, dated, signed by the engineer, emailed to the client within 24 hours of the visit.

Additional Tasks (Annually or as Required)

• Coil deep clean with approved chemical cleaner (annually for offices, quarterly for kitchens and dusty environments).
• F-Gas leak check using electronic refrigerant detector (UK mandatory frequency based on refrigerant charge per F-Gas Regulations).
• Refrigerant top-up where leakage has been identified, traced and repaired (we do not top-up without finding the leak first, this is illegal under F-Gas in the UK and bad practice everywhere).
• Belt replacement, fan bearing replacement, and capacitor replacement under the planned replacement schedule.
• Duct inspection and cleaning (typically every 18–24 months).
• BMS report download and analysis where the system has BMS integration.

AC Maintenance Contracts in London

How Often Should London AC Be Serviced?

For most commercial London installations, twice-yearly servicing is the right cadence, once in spring before the cooling season, once in autumn before heating-mode use (heat pump systems). This matches CIBSE TM44 guidance and SFG20 best practice for office, retail and most commercial environments.

Higher-cadence servicing is recommended for:

• Commercial kitchens, restaurants and dark kitchens quarterly (4 visits/year). Grease loading on condensers and indoor coils is severe; filter loading is heavy.
• Healthcare environments: quarterly. Indoor air quality is regulated, and clinical environments cannot tolerate filter degradation.
• Server rooms and data centres, quarterly minimum, monthly for critical infrastructure. Cooling failure means hardware damage.
• Heritage buildings, quarterly. Older buildings often have less stable internal environments, and concealed installations need closer monitoring.
• High-rise commercial buildings with over 250kW total cooling capacity, TM44 inspection every 5 years is mandatory under Building Regulations Part L.

F-Gas Compliance in London

The UK F-Gas Regulations 2015 set mandatory leak-check frequencies based on the refrigerant charge in each system, measured in tonnes of CO₂ equivalent (tCO₂e):

Every J SONS & CO. PPM visit includes the F-Gas leak check appropriate to the system. We maintain the F-Gas log for the system and produce it on demand for audits, insurance renewal, building inspections and ESG reporting. Operating a refrigerant system without the correct F-Gas record-keeping is a regulatory offence in the UK with civil penalties up to £200,000.

London PPM Contract Pricing

Indicative pricing fixed-price contract issued after a free site survey and asset register. Prices include scheduled visits, written condition reports, F-Gas leak checks, F-Gas log management, refrigerant pressure verification and priority response on reactive call-outs. VAT additional.

What is included as standard: scheduled visits, all consumables (filters, drainpan tablets, contactor cleaner), F-Gas leak detection and log keeping, written reports, asset register maintenance, priority emergency response within 4–24 hours by contract level, 10% discount on parts replacement, 10% discount on reactive labour outside contract scope.

What is typically additional: parts replacement (compressors, PCBs, fan motors, capacitors), refrigerant top-ups (after leak repair), coil chemical deep clean, ductwork cleaning, system upgrades or modifications.

London Reactive Call-Out Rates

For clients without a contract or for out-of-scope emergency work for contract clients:

• Standard hourly rate: £85–£125 per engineer hour (commercial)
• First-hour call-out charge: £110–£165 (includes travel to site)
• Out-of-hours rate: 1.5× standard (evenings, weekends)
• Public holiday and emergency response: 2× standard

Contract clients receive a guaranteed response time, a discounted hourly rate, and priority ahead of non-contract work.

What Differentiates a J SONS & CO. Maintenance Contract

Written checklist per visit. Not a tick in a box. Every visit produces a 1–2 page condition report with photos, pressure readings, electrical readings, observations and recommended actions. Emailed within 24 hours.

No mystery refrigerant top-ups. Refrigerant does not get used up in a sealed system. If pressure is low, there is a leak. We trace and repair the leak before topping up; this is the law in the UK under F-Gas.

The compliance log is managed by us. F-Gas log in the UK. Asset register kept current. Audit-ready at any time.

Fixed-price contracts. No “minimum visit” clauses, no surprise charges. The annual contract price is what you pay for the contracted scope. Variations are quoted separately and require client approval before work starts.

One contract across both countries. Multi-country clients with operations in both London and Harrow get a single master agreement, one named account manager, aligned reporting formats and consolidated invoicing.

Transparent reactive pricing. Hourly rates, call-out charges, and after-hours premiums are all published upfront in the contract. No surprises on the invoice.

Takeover surveys for existing systems. If you currently have a contract with another provider and want to switch, we run a documented takeover survey to establish the baseline condition of every asset. This protects both sides and stops you from inheriting blame for pre-existing faults.

Sectors We Maintain AC For

Offices, co-working spaces, corporate HQs, retail stores, supermarkets, restaurants, cafés, dark kitchens, hotels, boutique hotels, serviced apartments, schools, nurseries, universities, healthcare clinics, dental practices, GP surgeries, veterinary surgeries, private hospitals, gyms, leisure centres, hair salons, beauty clinics, warehouses, distribution centres, data rooms, server rooms, places of worship, listed buildings, embassies, residential apartments, villas and luxury private homes, across both cities.

Frequently Asked Questions

How often should commercial AC be serviced?

In London, twice a year is the standard cadence for typical commercial offices and retail. In London, quarterly is the standard for the same building types because of the climate. Higher-cadence servicing, bi-monthly or monthly, applies to kitchens, healthcare and server rooms in both cities.

What is F-Gas and why does it matter in London?

F-Gas (Fluorinated Greenhouse Gas Regulations 2015) is UK law governing the handling of refrigerants in AC and refrigeration equipment. It mandates leak-check frequency, record-keeping and engineer qualifications. Operating a system without compliant F-Gas record-keeping carries civil penalties up to £200,000. J SONS & CO. manages the F-Gas log as part of every London PPM contract.

What does PPM typically cost in London?

For twice-yearly PPM on a standard commercial AC unit, £240–£380 per unit per year. Quarterly PPM on restaurant or healthcare units, £420–£680 per unit per year. Server room monthly visits, £1,100–£2,400 per unit per year. Volume discounts apply for multi-site portfolios.

Is refrigerant top-up included in the contract?

No, and any contractor offering “free refrigerant top-ups” should be a red flag. Refrigerant does not get consumed in a sealed system. If the charge is low, there is a leak that must be traced and repaired before charging. In the UK, this is mandatory under F-Gas. Where a leak is found, we quote the repair and the recharge transparently.

Can you take over a maintenance contract from another provider?

Yes. We carry out a documented takeover survey of every asset, photographed, condition-rated, with a noted list of pre-existing faults. From that baseline, we issue the new PPM contract. This protects both sides: you get a known starting record, and we are not liable for pre-existing problems we did not cause.

Do you maintain systems you didn’t install?

Yes. The majority of PPM systems on our books were installed by other contractors before we took over. We work on every major brand Daikin, Mitsubishi Electric, Toshiba, LG, Panasonic, Samsung, Hitachi, Fujitsu, Trane, Carrier, York, GREE, Midea, SKM.

What happens if a unit fails between PPM visits?

Contract clients get priority emergency response with guaranteed response times, typically same-day within zone in London, within 4 hours in Harrow or all over the UK for hospitality, healthcare, retail and data clients. Out-of-scope repairs are quoted before work proceeds. Contract labour rates are discounted vs. non-contract clients.

Do you maintain VRF and VRV systems?

Yes. We hold the technical training for Daikin VRV, Mitsubishi Electric City Multi, Toshiba SMMS, LG Multi V, Samsung DVM S, Hitachi Set Free and Fujitsu Airstage. VRF maintenance is priced per indoor unit on a quarterly visit cycle in both cities.

Is duct cleaning part of an AC maintenance contract?

Standard PPM does not include duct cleaning because it is needed every 18–24 months rather than every visit. It is quoted separately when the duct inspection at a PPM visit shows it is due.

Request a Maintenance Contract Quote

For London PPM enquiries

Phone: +44 20 8050 7969

Email Address: info@jsonsco.com

Address: Wembley, London, United Kingdom, HA9 Emergency line 24/7 for contract clients.

Or use our contact form, and our PPM/AMC team will respond within one working hour during office hours with a tailored proposal.