This upgrade to our 334 improved thermal stability and accuracy but the biggest improvement is using a fan to lightly circulate the air around the TT. A 5ver may not have this issue but we struggled with this TT getting air temp consistent. Mounted a Vornado fan in the master br, and use a lasco wind machine on low in the kitchen. Our heater is in the rear bunkhouse, even with back duct closed off. It gets hot as hell back there shutting the thermostat off while the front master br is cold. AC is the same which uses ceiling ducts so the duct work is fine, it's just our layout and having a 37' TT.
East Bound & Down- We Love Camping :)