We just discovered a problem with our furnace and so I wrote about getting a furnace tune-up before winter. The blower switch had gone out on ours and it's going to cost about $50 to fix. It's a do-it-yourself job for anyone who's relatively handy (luckily both sons and husband are). The tune-up we're leaving to HVAC professionals. That's a little more intensive job. But there's another DIY job you can and should do with your furnace, in fact all your appliances: clean or replace furnace filters. Dirty filters blow dust back into the air. This is not only messy, it's unhealthy and unsanitary. It wreaks havoc with allergies. Dirty filters pose fire hazards. Read moreDIY Furnace and Appliance Maintenance Tips