Hi, Klover,
in case you should happen to check back, I'd just like to toss in 2 cents worth of; not thinking Bronzecat or anyone else meant to attack you, but was pointing out previous advice given; I've seen a number of people make multiple posts when their old one disappears and that doesn't seem to be an issue; and most people here are happy to help.
I think it was just being pointed out that without a thermometer, it's not possible to even guess at temps. in aquaria, because the perception of heat or cold to the touch is very subjective and degrees of inaccuracy vary widely.
That, and it only seems to be possible to keep bettas warm enough without a heater when the room's hot enough to make a dog pant and jump off the bed to go sleep in the hall. (My subjective measurement involves pet reactions, lol...)