This works as advertised. Connect it, turn it on and there it is. There was no visible mold in our furnace and this is to be preventative, so I don't know if it gets rid of mold for sure. Other reviews I've read swear it works though.
It took about 2 hours for me to install. It requires drilling some holes in the furnace and splicing electrical wires. It's a good idea to have it professionally installed if you don't have experience doing that stuff.
I didn't like the magnet idea, so I took the magnet off and bolted it on. That makes it more difficult to change the light bulb though.
Please take the warning of eye damage seriously. There was a small light leak from our furnace. I just glanced at it for a second to put on duct tape over the seam and I was seeing spots for hours. Luckily the spots went away.
Bought back in December for summer in Florida. Went to install Monday the 22. All went well. Easy to find location with magnet or screw mount. Wiring was easy and job completed in a half hour. Went to plug in bulb, opened hard plastic and bulb was cracked. E-mailed company, representative there, es.tech asked for my address. Received bulb the 23 rd, plugged in and working well. Outstanding customer service coupled with great value makes this a no brainer!!