furnace upgrade?

we want to use our TM in cold weather.. do we need to upgrade the current 16,000 BTU furnace?

thanks for any feedback?

How cold? But, I don't think so reguardless. We have been out while in the mid 20's and had no problems, in fact we took turns getting up to turn the heat down.

When we have shore power, we heat using a small electric space heater and it keeps kicking off and on. These things really do keep the weather out pretty well.