Germination heat source

[durable_now]

I have heard suggestions that you could use a waterbed heater for seed germination so I checked around and a friend of mine that owns a waterbed says
the instructions states that you should not turn on the heater untill the matress is full of water so this suggests to me that there should be a mass on the heater to absorb the heat & I don't think that a bunch of small container would provide that mass.The heat range is from 60 to 99 & that makes me believe that a 80 degree setting woud cause any harm even if nothing was on top of the mat except that the mat may have to have something on top of it to pull the heat away from the mat .If anyone has used one of these PLEASE let me know your results.I need cold hard facts 'cause I don't want to hook this thing up & 2 hours later go back & see smoke & flames shooting up to the ceiling from over heating.I have been using small heating pads for years & no problems BUT???.Any bonafied info will be GREATLY appreciated