20 Gallon Tank Heater strength?

[Candace]

This winter is going to be lean, so the house will probably be in the low to mid 60’s (Fahrenheit). Will an aqueon preset heater at 100 watts work with lower temperature’s or should I get the preset 200 watt for my 20g long? (No adjustable heaters, I’ve not had good experiences in the past with them staying steady and accurate)

 

[John58ford]

If you are down in the low 60s in the room, but aiming for 78 in the tank, 10 watts per gallon will work the best. If you are running "cold" water or fish that are good at 68-74 you could use 5 watts per gallon and do well. 10 watts per gallon is a maximum, you could probably do ok with 7.5 per gallon with ~15 degrees room to tank difference.

If you want to get super efficient, you can foam board and tape the sides and back panels, use a well fitting glass lid, and a true hood helps too. If looks mean nothing, a set a top hood fashioned from the same insulating foam board will keep the heat from your light heat and excess tank heat in. Personally, I would probably do 10w per gallon and see how it does though.

 

[Candace]

If you are down in the low 60s in the room, but aiming for 78 in the tank, 10 watts per gallon will work the best. If you are running "cold" water or fish that are good at 68-74 you could use 5 watts per gallon and do well. 10 watts per gallon is a maximum, you could probably do ok with 7.5 per gallon with ~15 degrees room to tank difference.

If you want to get super efficient, you can foam board and tape the sides and back panels, use a well fitting glass lid, and a true hood helps too. If looks mean nothing, a set a top hood fashioned from the same insulating foam board will keep the heat from your light heat and excess tank heat in. Personally, I would probably do 10w per gallon and see how it does though.

I have tropical fish - I’ll get the 200w and do the foam around the sides, thank you! Luckily I already have a tight fitting glass lid.