I'm going to make the short and sweet.
Bought the best pair they made at NWTF. Got them in the mail 4 weeks later than they were suppose to arrive. After I got them I'm pretty sure they didn't design them for my heating needs as I had trouble with them from day one. So I made three attempts to get help with them with no response. So I packed them up and sent them back asking for a refund. Guess what I had a response immediately. All they wanted to do was say how I had not tried to reach them and that the 30 day return policy had come and gone. I tried to be reasonable but they had no interest in working with me. All they wanted to do was blame me and all but said I was out of luck. Because they wouldn't respond I ended up going a different direction with a local company which I recommend you all to do. This company will not stand behind their product. If you look hard you will find many reviews just like mine. Wish I had done my homework.