Doing the calculations consider the fact that the basic RV AC unit requires around 4000 watts of power. A quiet camping Honda generator only puts out about half that.  I saw one camper who had two of those connected in parallel. So we need all of that for AC unless you are going to splurge for an elaborate solar and battery bank system. Then for heat you need something like a Mr. Heater buddy space heater that runs on propane. Here’s a rundown for the typical prices for all of this.  

This means you need 2600 bucks up front just for heat and AC. However we haven’t added up the cost of propane and gas. The generators are guaranteed for 10 years so we’ll just use this as a guesstimate. I live in the Midwest where we typically have about 4 months of high temps and 4 months of low tempts. The spring and fall are manageable. The generators only use about 1 gallon of gas a day so that works out to around 120 gallons a summer or 1200 gallons over the life of the generator. But we are using two so we’re talking 2400 gallons. At $2 a gallon (roughly) that is an additional $4800. Also the propane heater uses about 2, 1pound tanks a day at about $4 a tank which works out to about $9600 over ten years. That comes to a grand total of $17,000 dollars spent to stay warm and cool for the next ten years. The reason I worked it all out like this is because I wanted to break it all down to expense per day. That sounds like a lot of green but it really only works out to around $7 dollars a night. Here’s the funny thing. My four cylinder engine in my vehicle only burns about a fourth of a tank of gas sitting in idle for 16 hours. It’s only got a 12 gallon tank which means I only use about 3 gallons of gas doing this. At 2$ a gallon this means I actually save about a $1 dollar a day just using the already existing heater and AC provided in the vehicle. So in light of all of this figuring I opted to not do anything but just to use the vehicles heating and air conditioning with the engine in idle.  Plus I don’t have to worry about my generators getting stolen or the hassle of installing a second AC unit. My vehicle had those annoying day runner lights that came on while the engine was running and to fix that I just located the fuse and popped it out. Now at night the lights only come one when I want them on and with the engine running you can’t even hardly tell its running. I hope this helps.