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Almost 5-fold Difference in Post-renovation Formaldehyde Removal and Cleaning Service Charges Consumers Should Note the Limitations of Different Types of Formaldehyde Removal Agents

  • 2023.10.16

To create an ideal home-sweet-home, renovation and decoration should not be overlooked. However, paints, adhesives, sealants, and newly purchased furniture all increase indoor formaldehyde concentration in newly renovated flats, so many consumers choose to engage formaldehyde removal services. Moreover, some would seek the services of cleaning companies to clean dust-filled flats after renovation. The Consumer Council has collected information on the charges and terms and conditions of 23 companies in the market that provide household formaldehyde removal and/or post-renovation cleaning services, and found varying calculation methods and a vast range in charges from $1,202 to $7,000. Consumers should also make careful comparisons on the scope of services, materials used and other details in order to choose the most suitable service provider.

In August this year, the Council surveyed service charges and terms of use from 56 companies providing household formaldehyde removal and/or post-renovation cleaning services. 23 companies responded to the enquiries, of which 19 provided both formaldehyde removal and post-renovation cleaning services, while the remaining 4 provided only one type of service.

Charges for Formaldehyde Removal Varied by Almost 5 Times

Formaldehyde is a volatile, colourless gas with an irritating odour, and has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) many years ago. Newly manufactured wood products such as flooring and furniture, and some fabrics may release higher concentrations of formaldehyde. Formaldehyde may also be released from glues, paints, floor coatings, plasterboards, ceiling tiles, and wood siding used in renovations. High concentrations of formaldehyde can irritate the eyes, nasal passages, and respiratory tract, causing redness and swelling of the eyes, tears, itchy or sore throat, and even respiratory difficulties and allergic reactions. Prolonged exposure to moderate levels of formaldehyde may also aggravate asthma symptoms. Formaldehyde emission is generally higher when indoor temperature and humidity are higher.

17 companies which provided formaldehyde removal services charged a total sum according to the area of the flat and/or the pieces of furniture, starting from $800; another 3 companies charged per square foot ranging from $2 to $7 each. Furthermore, some companies allowed consumers to choose the type or efficacy of formaldehyde removal sprays (e.g. general formaldehyde removal spray or anti-mould and anti-bacterial formaldehyde removal coating, etc.) before charging according to the size of the unit, while a small number of companies set a minimum charge ($1,400 to $3,000). All in all, there are considerable charge discrepancies among companies, for example for a unit with 601 square feet to 800 square feet of usable floor area, basic charges among different companies ranged from the lowest of about $1,202 to the highest of $7,000, a difference of nearly 5 times.

These companies usually measure formaldehyde levels in a flat before the actual formaldehyde removal process. Among the 23 surveyed companies, 4 did not charge an inspection fee, 1 indicated they would charge a $1,000 inspection fee if service is provided in remote areas such as outlying islands, while the remaining 19 companies charged inspections either as a one-off fee (from $500) or by square foot (from $1.5 per square foot). 11 companies offered deduction of inspection fee from final charges if customers used their services. Besides, 6 companies offered other concessions to customers, such as discounts on the whole bill or inspection fee, cash rebates, etc.

Photocatalytic Decomposition of Formaldehyde May Be Impaired by Insufficient Irradiation

Consumers Should Also Be Aware of Secondary Contamination

To achieve the best results in formaldehyde removal, it is usually necessary to remove dust from furniture, or do some simple cleaning before applying the chemicals. Technicians will first measure formaldehyde levels at different locations of a flat before the process to assess the source of formaldehyde emission, then apply formaldehyde removal spray on all walls, ceilings, and surfaces and interior of furniture.

The surveyed companies commonly used “photocatalysts” and “non-photocatalysts” preparations as formaldehyde removing agents. Photocatalytic materials utilise photocatalysts in combination with light to induce photocatalytic decomposition, breaking down formaldehyde and other volatile organic compounds (VOCs). Currently the most widely used photocatalyst is titanium dioxide (TiO2). When these photocatalytic materials are exposed to an appropriate and sufficient intensity of irradiation, reactive oxygen species are produced to react with air pollutants on the surface of the material, converting them into water and carbon dioxide. However, without appropriate and sufficient light exposure, the effects of these catalysts are limited. In addition, degradation rate will be significantly reduced in an environment with low VOCs concentration. On the contrary, if oxidation is incomplete, there is a chance that substances more harmful than the original VOCs would be formed. For instance, they could be converted and cause secondary formation of formaldehyde, or be converted into acetaldehyde, which is another chemical with a pungent smell, irritating to the eyes and mucous membranes, and also carcinogenic. Generally, if companies adopt a combination of methods to remove formaldehyde, such as using an air pump to increase indoor ventilation after spraying formaldehyde removing agents, it could theoretically reduce the effects of “secondary contamination”.

On the other hand, some companies use “non-photocatalysts” (also known as “air catalysts”) to remove formaldehyde. Theoretically, “non-photocatalyst” materials mainly make use of oxygen in the air to decompose formaldehyde and other VOCs through catalytic oxidation. However, the type and physicochemical properties of the catalyst, as well as its stability, indoor temperature and concentration of air pollutants may severely affect its degradation efficiency. The presence of other pollutants may also cause deactivation of the catalyst.

According to an expert in biological and chemical technology, formaldehyde will continue to be released from furniture or paint even after the removal process has been completed, and may accumulate in indoor environments to harmful concentrations, thus consumers should pay extra heed and keep the interior space well-ventilated.

Furthermore, when choosing a service, consumers should pay heed to whether a warranty period is offered, within which consumers could request a review of the formaldehyde concentration by the service provider. If the index is found to be higher than safety standards, consumers could request provision of the same service free of charge. Even after the formaldehyde removal process, formaldehyde could still be continuously emitted from furniture or paint. If the service has warranty, consumers could request the company to retest the formaldehyde levels within the warranty period. 

Most Post-renovation Cleaning Excludes Waste Disposal

Even if formaldehyde removal is not required, flats are usually covered with dust after renovation, and many consumers would choose to hire a cleaning company for a deep clean. In this survey, 20 companies provided post-renovation cleaning services, and all indicated that they would clear dust, clean windows, cabinet interiors and surfaces, windowsills, balconies, metal gates, appliance surfaces, surfaces of taps and showers, kitchen sinks, toilet basins, towel racks, stainless steel shelves and other small parts. However, 4 companies excluded the cleaning of certain common items including doors and door handles, ceilings, bathtubs/shower trays, shower panels, toilet bowls, crevices, walls and/or skirting. Regarding charges, companies set total charges according to the area of the unit, by each square foot, or by the hour and the number of service staff. Taking for example a flat with a usable floor area of 601 square feet to 800 square feet, the basic charges of 20 companies ranged from around $1,120 to $7,000, a difference of over 5-fold. As for payment methods, 7 companies allowed consumers to pay after completion of service, while the remaining 13 companies required consumers to pay a deposit of 10% to 50% or $500 to $2,000, with the remaining balance to be paid after the completion of service.

In case of accidental damages of furniture or objects in the flat by service staff during cleaning, apart from 1 company which denied all liability for damage, and 2 companies which offered restitution discussions with consumers depending on the situation, the remaining 17 companies had corresponding compensation plans, with a maximum compensation ranging from $200 to $1,000, or up to 30% of the service charge. Among them, 3 companies indicated provision of compensation by insurance or on a pro-rata basis without setting a maximum payout amount, which would give consumers more confidence.

Consumers should be aware that some companies with lower basic charges may not provide certain services, and may also impose minimum charges and surcharges for services delivered to remote areas such as outlying islands, on public holidays or before festivals. Consumers should also pay attention to whether the costs of cleaning supplies and tools are included in the basic charges. Some companies also stated that services did not include disposal of construction waste, furniture, and rubbish. If consumers are not satisfied with the standard of cleanliness, 16 companies would re-clean problematic areas free of charge.

As there are many service providers on the market and their charges and scope of services vary greatly, consumers should ask relevant companies for details and compare carefully, as well as paying heed to these tips:

  • Before confirming services, consumers should ask the company for documents including a contract and/or an invoice listing out the service details, such as the service items, basic and additional charges, and payment details, etc. If the company has provided pre-service points to note, consumers should understand the details before confirming the service, so as to protect their own rights;
  • Consumers should be mindful of the comprehensiveness of the test items provided by the company. Assessment of ideal indoor air quality should not be solely based on the concentration of formaldehyde, but also the concentrations of carbon dioxide, carbon monoxide, ozone, benzene, and other air pollutants;
  • Before carrying out the formaldehyde removal process, drawers, lockers, or wardrobes should be emptied while food, beverages, and cutlery should be put away to facilitate spraying of formaldehyde removing agents;
  • Residents and pets should leave the flat before the procedure, or wear masks if it is necessary to stay in the flat;
  • Do not move into the flat immediately even after service but open the windows to let the air circulate for a few days before moving in to ensure good indoor air quality;
  • Check whether the service comes with a warranty period.


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