Besides wrapping a blanket around your beloved brew baby in the cooler months, there is the option of more reliable heating. The Brew Shed stocks both heat pads and heat belts. Both come from reputable suppliers. Both are set to run at a set temperature with no thermostat to switch it on and off. This is a good thing for two reasons. 1) Thermostats can break, so not having an extra part is better for longevity. 2) Consistency is key. Your brew will be much better if you can maintain a constant temperature instead of it going up and down.
The temperature is set at around 28 on both appliances. This is a good temperature for cold weather brewing because due to heat loss and ambient temperatures it will not heat the entire brew all the way through at 28. It will more likely be around 24 ish.
Heat pads are made to take the weight of the fermenter complete with wort in it, so around 25-30 kgs. If you do a double brew in a 60l fermenter you should think about using a heat belt.Also if you have a Stainless steel fermenter with a plastic base then a belt is best.
The heat pad gives an even distribution of warmth due to heat rising through the brew, and is more efficient because almost the entire heating surface area is in contact with the fermenter.
The brew belt on the other hand has one side always exposed to the air and only heats at the level of which it is placed on the fermenter. The brew does circulate however due to the activity of the yeast. A con of the brew belt is that the plastic sleeve which the element sits in can become brittle after time, the heat pads seem to be sturdier for use winter after winter.