How to Check HCHO and TVOC After Home Renovation Using NOYAFA JMS11 or JMS12 Malaysia

Checking Indoor Air After Home Renovation

New paint, cabinets, flooring, wall panels, adhesive and furniture may release volatile compounds into indoor air. The smell may be especially noticeable when a renovated room remains closed for several hours.

The NOYAFA JMS11 and NOYAFA JMS12 provide a convenient way to perform an initial check for:

Formaldehyde—or HCHO
Total volatile organic compounds—or TVOC

The JMS12 also displays:

Temperature
Relative humidity

These portable instruments are useful for screening and comparison. They can help homeowners observe whether readings change between rooms, after ventilation or over several days.

However, correct measurement technique is essential. A single reading taken immediately after switching on the instrument may not represent the overall condition of the property.

Which Model Should You Use?

NOYAFA JMS11

Choose the JMS11 if you require a simple and economical detector for:

HCHO screening
TVOC screening
Occasional home checks
Comparing newly renovated and unaffected rooms
Checking furniture, cabinets or vehicle interiors

The JMS11 uses replaceable batteries and is suitable for straightforward testing without additional temperature and humidity measurements.

NOYAFA JMS12

Choose the JMS12 if you also want to record:

Room temperature
Relative humidity
HCHO
TVOC

The JMS12 is the more complete choice for repeated checks because temperature and humidity provide useful context when comparing measurements taken at different times.

What Should Be Checked After Renovation?

Potential sources of HCHO and TVOC may include:

Built-in cabinets
Particleboard furniture
Laminate flooring
Wooden wall panels
Adhesive
Sealant
Paint
Coating materials
Curtains and upholstery
Cleaning chemicals
New mattresses
Recently installed decorative materials

The presence of a strong smell may indicate volatile substances, but odour alone cannot identify a particular chemical or determine its concentration.

Similarly, the absence of a noticeable smell does not automatically confirm that the room contains no volatile pollutants.

When Should You Take the First Reading?

A newly renovated room may produce unstable readings while paint, adhesive and other materials are still drying.

An initial check may be conducted after the main renovation work has finished, but it should not be treated as the final result.

For a more useful evaluation, perform several checks:

Before ventilation
After ventilation
At the same time on another day
In different rooms
Near new materials
Away from the suspected source

Repeated measurements make it easier to identify patterns.

Step-by-Step Testing Method

Step 1: Remove immediate interfering products

Before testing, avoid using:

Perfume
Air freshener
Alcohol-based sanitiser
Cleaning spray
Insecticide
Aerosol products
Strong solvent

These products may temporarily affect semiconductor gas sensors and produce elevated readings.

Step 2: Prepare the room

Decide whether you are testing:

The room under normal occupied conditions
The room after it has remained closed
The effect of ventilation

Record the condition so the result can be compared correctly later.

Do not compare a closed-room reading with another reading taken while every window and door is open without noting the difference.

Step 3: Switch on the instrument

Turn on the JMS11 or JMS12 in a clean, ventilated environment whenever practical.

This helps reduce the influence of pollutants that may have accumulated around the sensor during storage.

Step 4: Place the tester correctly

Position the detector in an open area where air can flow through its ventilation openings.

Avoid placing it:

Directly on a newly painted surface
Inside a cabinet during the first general room test
Immediately beside an adhesive joint
In front of an air-conditioner outlet
Beside an open window
In direct sunlight
Above an open chemical container

The purpose of the first test is to understand the general room condition rather than measure the strongest possible concentration at the source.

Step 5: Allow the reading to stabilise

Do not make a decision based on the number displayed immediately after entering the room.

Allow sufficient time for the sensor to respond to the surrounding air. Keep the tester in the same location during this period.

Step 6: Record the reading

For the JMS11, record:

HCHO
TVOC
Location
Time
Door and window condition

For the JMS12, also record:

Temperature
Relative humidity

Step 7: Test several locations

A practical sequence for a renovated bedroom is:

Centre of the room
Near the new wardrobe
Near the flooring
Beside the bed or normal breathing area
Another room without recent renovation

This helps determine whether an elevated reading appears throughout the room or mainly near one material.

Step 8: Ventilate and repeat

Open the doors and windows to increase fresh-air exchange. If available, use suitable mechanical ventilation.

After ventilation, repeat the measurement at the same location.

Use the same instrument and similar measurement duration to make the comparison more meaningful.

How to Compare Before and After Ventilation

A simple test record may look like this:

Location	Room condition	HCHO	TVOC	Temperature	Humidity
Bedroom centre	Closed	Record reading	Record reading	JMS12	JMS12
Bedroom centre	After ventilation	Record reading	Record reading	JMS12	JMS12
Near wardrobe	Closed	Record reading	Record reading	JMS12	JMS12
Unrenovated room	Normal	Record reading	Record reading	JMS12	JMS12

If the reading falls after ventilation and rises again after the room remains closed, an indoor source may still be releasing volatile compounds.

This observation does not identify the exact material. Further investigation may be required.

Should You Test Inside a Cabinet?

Testing inside a cabinet can be useful, but it should be treated as a source-investigation test, not a measurement representing the entire room.

A closed cabinet may accumulate a higher concentration than the occupied area of the room.

Use two separate checks:

First, measure the general room.
Then, check inside or immediately beside the cabinet.

Clearly label the readings so they are not compared as if they were taken under identical conditions.

Why Are the Readings Higher During Hot Weather?

Higher temperatures may increase the release rate of volatile compounds from some materials.

A room that has remained closed during a hot Malaysian afternoon may therefore produce a different reading from the same room early in the morning.

This does not automatically mean that the tester is inaccurate. It may reflect a genuine change in the room environment.

The JMS12 is particularly useful for this comparison because it displays temperature and humidity alongside HCHO and TVOC.

Why Does the Reading Increase When the Air Conditioner Is Switched Off?

Several conditions may change when the air conditioner is turned off:

Room temperature may rise.
Air circulation may decrease.
Fresh-air exchange may remain limited.
Volatile compounds may accumulate.
Humidity may change.

Record whether the air conditioner was operating during every test. Measurements should be compared under similar conditions whenever possible.

Why Does the Reading Increase Near Cleaning Products?

Many cleaning products release volatile compounds. Perfume, sanitiser, detergent, floor cleaner and aerosol spray may affect the TVOC response.

If cleaning was recently completed:

Remove the chemical products from the test area.
Ventilate the room.
Allow the environment to stabilise.
Repeat the measurement.
Compare the new reading with the earlier result.

A sudden temporary increase does not necessarily mean that renovation materials are the only source.

Can JMS11 or JMS12 Confirm That a Room Is Safe?

The JMS11 and JMS12 are suitable for initial screening and comparative checks.

They should not be used alone to issue a formal declaration that a room is safe, compliant or completely free from pollutants.

Professional assessment may be required when:

Occupants experience persistent discomfort
Readings remain elevated after ventilation
A formal report is required
The property is involved in a legal dispute
Employee exposure must be evaluated
Regulatory compliance must be demonstrated
A specific chemical must be identified

Portable semiconductor detectors respond to environmental conditions and potentially interfering gases. Laboratory or professional testing uses different sampling and analytical methods.

What Should You Do If the Reading Remains High?

If the reading repeatedly remains elevated:

Increase ventilation

Improve outdoor-air exchange by opening suitable doors and windows or using mechanical ventilation.

Remove suspected products

Temporarily remove movable items such as new furniture, cleaning chemicals or stored solvent products and repeat the test.

Isolate the suspected area

Compare the affected room with another area that has not been renovated.

Record a trend

Take readings over several days under similar conditions.

Seek professional assessment

If the issue continues or occupants experience health concerns, consult an appropriate indoor air quality or environmental professional.

JMS11 or JMS12 for Renovation Checks?

Choose the NOYAFA JMS11 if:

You need basic HCHO and TVOC screening
You only perform occasional checks
You prefer replaceable batteries
Your main priority is affordability

Choose the NOYAFA JMS12 if:

You also need temperature and humidity
You want a more complete test record
You perform repeated room inspections
You prefer rechargeable operation
You want to compare changing environmental conditions

For repeated renovation checks, the JMS12 is generally the more informative model. The JMS11 remains a practical entry-level choice.

Buy NOYAFA Air Quality Testers in Malaysia

MTM Precision supplies the NOYAFA JMS11 and JMS12 for indoor air quality screening in homes, offices, rental properties and renovated premises.

JMS11 and JMS12 availability
Suitable model for renovation checks
Alternative PM2.5 and CO2 monitors
Product specifications
Basic operating guidance
Delivery throughout Malaysia
Collection from our Puchong showroom

Contact MTM Precision

MTM Precision Sdn. Bhd. (744811-A)

Telephone: +603-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com / enquiry@mtmpre.com.my
Website: www.mtmpre.com.my

Showroom & Service Centre:
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia.