Quote Originally Posted by random-cichlid
ok i just measured room it is pretty close to 5.7L x 2.9W x 2.8H
One side is already insulated and the roof is also insulated
I need some ideas on what i should use for insulation i want to go the cheapest way but still being efficient at the same time and im not to sure about how i shall heat the room whether it be a reverse system ac or a electric radiator what does the majority use
if your doing it on the cheap think thermal mass, the more tanks you have and the tighter you cram them together the warmer the room stays.

as Kath said batts are good but work better if you integrate them with other materials, ie a layer of foil insulation, then batts then more foil and maybe a plywood sheet or styrofoam to finish it up on the inside. such a system has almost 0 loss.

A radiator heater will give you 1 watt of heat for 1 watt of power (resistance heating an electric heater that converts electricity into heat).

An AC will give you up to 4w of heat for every 1watt of power, as all your doing is moving kinetic energy from the air outside into the air inside the fish room (on most domestic units this only works if the outside temp is above -12 degree celcius).

Seriously if its a new room, to set it up right will save you a fortune over the year especially with power prices on the up and up you'd be crazy not too.