Approximately four weeks ago, my husband installed an all-house humidifier. Approximately two weeks ago, we started hearing an annoying rattling hum from the cold air duct returns on the main and second floors. If we remove a filter (from either floor, it doesn't matter which) the rattling stops. Is this because of the humidifier? Is it because we are using the wrong type of filters (90-day types that filter just about everything under the sun)? We changed the filters when my husband installed the humidifier and last weekend so we believe they aren't dirty enough to be clogged. It is so disruptive that no one in the house can sleep without shutting their doors. And of course that does nothing for the daytime disturbance. Does anyone have suggestions?

Hi, Our son and daughter-in-law, just out of school, have just bought a small (<2000 sq ft) ranch-style house in southern California, built in the 70s. The furnace doesn't seem to make the place warm enough, so they called a furnace repair company to see what should be done. They were told they need a new furnace, a new central air-conditioner, and all new ducting because their duct work has asbestos. It will cost a fortune! We've never seen the house so we can't judge whether they've been given accurate information. I have two questions for any of you who may be able to offer advice: #1 - Would a heat pump work to both heat and cool in Orange County,CA? and #2 - is there any way we can advise the kids how to choose/judge a heating and air conditioning company? Ratings, professional organizations, etc.? We'd hate to see them get into a mess. Thanks for whatever thoughts you have.