The seasonal cooling checklist

The whole argument of this page is timing. Every item below is easier, cheaper and more effective done before you need it.

1. Clean the filter. The highest-value maintenance on any air conditioner. A blocked filter starves the evaporator of airflow, so capacity falls and run time rises — you pay for it twice. The full routine.
2. Check the coil and fins. Behind the filter is where the finer material ends up. Bent fins and a dusty coil both cost you heat transfer.
3. Check the drain path. Condensate has to go somewhere, and a blocked path is a water problem before it is a cooling one — how drainage works.
4. Test it before you need it. Run the unit for an hour on a mild day. Finding a failure in April is an inconvenience; finding it in a heatwave is a week of waiting.
5. Replace evaporative pads. The cooling happens at the pad, and a degraded one takes most of the performance quietly.
6. Reverse ceiling fans to downdraft. Ten seconds, and it is the difference between a fan cooling you and a fan mixing the ceiling.
7. Check for wobble. A wobbling fan is a mounting or balance issue that gets worse, not better — how to fix it.
8. Shade the glass. The one intervention with no running cost at all, and the one that decides how hard everything else has to work.

• Filter, every two to four weeks. Check your manual, since intervals vary with filter type. This is the one recurring job that genuinely matters.
• More often with pets. Hair loads a filter and a grille far faster than dust alone.
• Watch for ice. A frozen coil means airflow or refrigerant trouble, and running through it makes things worse — what the symptoms mean.
• Drain and refill evaporative coolers regularly. Standing warm water is a maintenance commitment, not an optional one — the cleaning routine.
• Clean fan blades. Dust on a blade edge costs airflow and unbalances the fan — how, without breaking it.

1. Drain everything that holds water. Evaporative coolers, misting fans, condensate trays. Water left through a freeze is how these die — the shutdown routine.
2. Disconnect hoses from misting equipment. A hose left connected over winter can freeze and split, and the equipment goes with it.
3. Remove or cover window units. An installed window unit is a hole in the wall all winter, and a cover on the outside is the minimum — removing and storing one properly.
4. Clean before storing, not after. Dust and moisture left on a coil for six months is worse than either alone.
5. Reverse ceiling fans to updraft, slowly. Moving warm air off a high ceiling without making a draft.
6. Keep the extract fans running. Ventilation is a year-round job, and winter is when indoor moisture is highest.

Every item above is cheap in April and expensive in July, for reasons that have nothing to do with the work itself.

• Failures are found on your schedule. A unit that will not start is a mild annoyance in spring and a serious problem in a heatwave.
• Purchases get made calmly. The single worst decision in home cooling is a large unit bought in the third week of a bad August — $260 a year of running cost, decided under duress.
• Load reduction has to be in place first. Shading only works if it is up before the sun is on the glass, and that is a seasonal decision.
• Availability. Everything in this category is easier to obtain before the weather turns.