The size of your home influences the choice and quantity of formaldehyde removal products. Larger spaces may require multiple air purifiers or specific technologies to address formaldehyde concentrations effectively.
Reference Guide:
Where can Formaldehyde be found typically? 
3-Room HDB Layout (60 to 65 square meters):
4-Room flat HDB (90 to 110 square meters):
Recommended usage for wardrobes:
Recommended usage for kitchen cabinets: