The useful task of the day: change the filter on the HVAC (Heating, Ventilation & A/C) system.
In the USA, well in California at least, we heat / cool homes by blowing hot or cold air through ducts to parts of the house. This is completely different from hot water radiators or underfloor heating. With this setup is you pull air from one part of the home (know as "The Return"), filter, heat / cool it, pump to other places (as far away from "The Return" if possible). This means you have a free whole-house air filter as long as you:
- Use a decent filter
- Replace it regularly
- Have a HVAC that allows you to just run the filter without any heat / cool
Filter manufacturers recommend you replace it every three months - of course they do - I find that every six is fine for us and set my thermostat to send me an e-mail reminding me to change it.
Filters come in different "strengths" depending on how much you want to filter. They all filter dust, pollen and the like. Higher grade ones also filter pet dander which as I don't have pets I've avoided. The top-grade ones also filter bacteria and viruses.
It won't take you long to figure out which grade of filter I just installed.