I installed the heat strip that I bought on the internet. I think it works OK. it can take the chill off in the morning but its not going to put out a lot of heat. The down side is the noise from running the overhead AC fan. I dont regret installing it. We use a 1500 watt ceramic heater for more heat trying to avoid using the LPG furnace. So far since we had our 2008 HTT we have not used the LP furnace, however the coldest temp we camped in was in the hi 40's.
Jim & Kathy
Bailey, waiting at the Rainbow Bridge
Gracie, a rescued Beagle
2007 Chevy Tahoe
2008 FR Surveyor 233T