50W heating system too much for 5 gallon cistern?

Might sound like a stupid query but my room gets really cold during the winter. While I'm at school we leave the house kiln off and the room temp drops to around 30-40 degrees.
I would have gotten a 25W but PetSmart apparently don't market any marineland ones under 50W. My mistake.
Do I have to return it? :[
i use a 55 watt in my 5 gallon

as long as its a heaterstat (turns of when it get to the right temp) you should be ok
50 watts is in recent times fine for a 5 gallon tank. A general rule of thumb is 5 watts per gallon of water; but the piece to consider for an aquarium heater is that you have enough dimensions to heat the water. You can't really get to much size, because the heater will only raise the dampen temperature to the point that you set it to.
Answers:    It will be fine, the thermostat will turn it off once the cistern gets warm enough. The bigger oven will just run for a shorter time.

If your room is getting that cold I would suggest you SHOULD have a 50w furnace, a smaller one may struggle to keep the temp up.

I have run a 50w in my 5gal, no worries.

Ian
50w will be fine. i also have a 50w furnace in my 5 gal which contains a betta. it keeps the temp exactly at 78. in recent times make sure to check the temp in luggage u got a malfunction one.
Eh, 25 would be a bit better, as even in a cold room in such a small body of wet it shouldn't be too hard to heat up.

You could use a 50w, just save it set a little lower, keep a thermometer in at hand and make sure to check periodically.
dude your gonna cook ur fish wit 50W heater just get a 10g reservoir for 15bucks its better then killin ur fish
What is protein skimming?   Can anyone describe me the moniker of these fish ?   If I use the Betta Plus river treatment for my betta's river, do I still hold to make tracks the sea out 24 hrs?   Would these fish be at odds together?