Literally two weeks ago, one of my best friend's wife goes to a property that I told him not to buy, 5 squatters were partying in it, heat was up high to 90, and he ended up fixing what they broke and spent 10K. 

If it's electric then they should not be taking the covers off the heating elements and messing with it.  

Both central heat and air system have been checked.

Do you have separate utilities, specifically heat?

Heating? 

It does not need hotwater as it heats up the water and uses that.My question is.

@Ian TudorThe park acrosss the street is quite a bit nicer with a double wide compatible lot, heated pool, clubhouse, water included in lot rent, and within a gated 55+ community.

Have provisions in your Lease like no going on the roof, cannot shut off the heat, no parking on the front lawn, etc.

I have used a different product that has a lower temperature requirement but that product will most likely be more expensive. 2. temporary enclose and heat the surface to the minimum temperature, install product, keep heating till its cured, then remove the temporary enclosure.

Community is building resort style pool, gym and yoga center, hike and bike trails, dog park - all included in HOA fees which is not high.