As we are having to strip down Cal's warm air heating system to service it and replace the air intake unit we have decided that it is time to also replace the ducting and whilst we are at it add some insulation to the new ducting to reduce heat loss in the ducting runs. Which in theory should result in warmer air coming from the vents, well that is the theory anyway.
We shall have to see if it works in practice as well as the manufacturers claim. Their claim is up to 40% warmer air coming from the vents. If true this will make it a worthwhile addition. If not we have probably just made ourselves a load more extra work for this coming weekend!