Preparing to process the turkeys in chilly mid-November (high around 20) forced us to think carefully about how we handled getting the scalding water to temp and keeping it there.
We made two changes that I think were massively helpful, and will even be worthwhile for warm-weather processing.
First, I insulated the scalding bucket (a large metal trash can) with water heater insulation. 
Second, rather than heat the water all from cold or manually carry buckets from the stove, we filled the tank with hot tape water from a faucet with a hose fitting. So we started at 120 deg. rather than 40 deg., which probably shaved about 43 quintillion hours (rough guess) off of our heating time. We then used the scalding water controller to bring it up to temp before even moving it outside. 
This did mean I needed to move a full 30 gallon bucket, but the hand truck and some tie-down straps made that not too big of a problem, and certainly worthwhile.
