Filters every two weeks? Sounds like a lot. Who actually does that?

Editorial guide · Updated 18 September 2026

In short Short answer: two weeks is what all manufacturers say (Daikin, Mitsubishi, LG, Panasonic) and the US DOE says monthly to bi-monthly in season – and the difference is not 'how the filter looks' but how much fine dust passes it once loaded and sticks to the wet evaporator, and how much extra the unit uses with a clogged filter (5–15%). The realistic compromise: every two weeks in July–August, monthly the rest of the time.

This page explains a situation in an editorial format. It is not an open discussion board or a verified customer review. Contact us on WhatsApp about your own appliance.

Situation discussed

Otopeni, house, 2 Panasonic units. I read in the manual 'clean the filters every two weeks'. Seriously? I wash them twice a summer and they look fine. What is the real rhythm, the one that actually matters, and what happens if not?

Editorial explanation · Revizie AC

What is really happening

A clean filter has two roles: it holds dust before the evaporator (filter efficiency and room particle concentration are the main drivers of coil fouling rate) and lets air through – a loaded filter cuts airflow, the unit cools less and runs longer. 'Looks fine' twice a summer means it sat loaded for 6 weeks each time. Sponge-type filters (on some models) are the worst: they hold 3–5 times more microbial mass than polyester ones and become a source themselves. Five minutes every two weeks is the cheapest item in the whole maintenance.

Maintenance follows actual use — Start with the manufacturer’s instructions.
Consider operating hours, environment and observations.
Plan checks and record completed work.
One fixed interval does not suit every unit and home.

What the studies say

Daikin, Mitsubishi Electric, LG and Panasonic recommend cleaning the indoor unit's dust filters every 2 weeks. [Daikin, 2023]
US DOE: filters should be cleaned or replaced every month or two during the cooling season, more often with constant use, dust or pets. [US Department of Energy – Energy Saver, 2024]
Replacing a dirty, clogged filter with a clean one can lower an air conditioner's energy consumption by 5–15% (US DOE). [US Department of Energy – Energy Saver, 2024]
Filter efficiency and indoor particle concentration are the most important factors determining how fast the evaporator fouls. [Lawrence Berkeley National Laboratory / , 2002]

What we do on site

At the annual visit we show you how to remove and refit the filters on your model (some Panasonics also have fine filters that are replaced every 6 months–3 years).
We wash the filters in lukewarm water with neutral detergent and dry them in the shade; if they are warped or torn, we tell you to order new ones (they are cheap).
The rest of the protocol: sealed double cover, alkaline detergent, adjustable pressure wash of evaporator, roller, pan and hose, sanitising, outdoor unit in place. See current rates on the Prices page.

What you can do yourself

Set a recurring phone alarm: 'AC filters' every 14 days, May–September.
Lukewarm water, a drop of dish soap, dry in the shade – not in the sun, not with a hairdryer.
With a dog/cat or a building site nearby, weekly.

What NOT to do

Do not refit wet filters – they mould on the spot.
Do not wash them with solvents or in the dishwasher.

Prevention

Filters every two weeks at peak season, monthly otherwise; internal sanitising yearly.

When to call us

0764 012 943, WhatsApp, Monday–Saturday 08:00–20:00; Otopeni is in our area.

Clean air conditioner with the louver open, in natural light

Ask your question Report an error

← I had it sanitised in March – do I need another at the end of summer?My electricity bill rose 30% this summer – could it be the dirty unit? →

Related threads

Editorial guide · How often

I had it sanitised in March – do I need another at the end of summer?

Explanations and useful checks for this situation: I had it sanitised in March – do I need another at the end of summer?

Answered by technicianRead →

Editorial guide · How often

Small office with 4 staff in Pipera – how often do we sanitise the two units?

Explanations and useful checks for this situation: Small office with 4 staff in Pipera – how often do we sanitise the two units?

Answered by technicianRead →

Editorial guide · How often

How often should sanitising be done? Does it depend on how much I use it?

Explanations and useful checks for this situation: How often should sanitising be done? Does it depend on how much I use it?

Answered by technicianRead →

Editorial guide · How often

Allergic child, unit in his bedroom – does it really need twice a year?

Explanations and useful checks for this situation: Allergic child, unit in his bedroom – does it really need twice a year?

Answered by technicianRead →

Editorial guide · Season

I use the unit for heating in winter too – does autumn cleaning still matter?

Explanations and useful checks for this situation: I use the unit for heating in winter too – does autumn cleaning still matter?

Answered by technicianRead →

Editorial guide · Cleaning

15-year-old unit, never cleaned inside – worth cleaning or should I replace it?

Explanations and useful checks for this situation: 15-year-old unit, never cleaned inside – worth cleaning or should I replace it?

Answered by technicianRead →

Preferences

Filters every two weeks? Sounds like a lot. Who actually does that?

What is really happening

What we do on site

What you can do yourself

What NOT to do

Prevention

When to call us

Related threads

I had it sanitised in March – do I need another at the end of summer?

Small office with 4 staff in Pipera – how often do we sanitise the two units?

How often should sanitising be done? Does it depend on how much I use it?

Allergic child, unit in his bedroom – does it really need twice a year?

I use the unit for heating in winter too – does autumn cleaning still matter?

15-year-old unit, never cleaned inside – worth cleaning or should I replace it?

Read also