I had 3 jobs between 600-800m2 EWI with 200mm insulation boards. When we started on the first the hand saw just didn't work, the hot knife was not long enough, the cut wasn't strait , and I decided to invest in hot wire cutter. The best think I did! Boarding was a dream! If you do insulatioon 100mm and above ,then is worth buying one,but if is less,then you will be alright with the hot knife. The smell on the other hand.......! When you choose hot wire make sure you know what do you want! In my case it needed to universal and easy to move around- no cables, and to be able to stand on its own and to be fixed to the scafold . Ended up buying one from Germany with battery and separate 230v cable. The best one I found at the time.The battery lasted good 3 days with extreme use. With the cutter you have and hot knife for free:RpS_thumbup:, which is not as quick as the 110v, but for the windows and small cuts is ok . One think you have to keep in mind is the boards have to be free of any dirt or ice, otherwise is very hard to cut through and very likely to brake the wire. Also don't tide the wire too much :RpS_blushing:. Happy shopping :RpS_thumbup: