Can anyone recommend a good furnace/duct cleaning place that doesn't charge a fortune? I saw a groupon that was regular $399 on sale for $49 which I'm hesitant to purchase so I thought I'd ask here first. This is the first year in my house and the previous owners had some type of Siberian cats and I just turned the heat on. So I just want to make sure everything is clean as I have asthma. TIA!