Dynamats is excellent stuff. Price is pretty steep.
Our dog house fits good and tight all the way around. Seals good.
My current situation is .... does not appear that I can lift the carpet without damaging it.
So, short term solution is to use that foil insulation (like people put in their windows) under out custom fit floor mats. Will have to glue carpet protector that has the nubbins to keep it from sliding to the back of the insulation. Then put the floor mats on that. Don't believe this is the best solution, its the only option I have for now. Plan to continue a search for a better long term solution. Seems like with all the people who have this problem that someone have designed a solution for sale...or the Motor Home mfg's would install insulation before they install the carpet. Frustrating.