I conducted research; reviewed RV owner web sites where others have installed fans on their RV's. Some RV MFG’s are now installing these as OE. The question is placement; everyone has an opinion, but there is only one right answer. I installed the fan on the roof under my exhaust vent because heat rises; many HVAC and RV web sites recommend this installation; you must REMOVE THE HEAT for the fan to do its job to keep the fridge cool. DO NOT install to blow over or through the coils; this does not remove the heat. Placing a fan inside the RV behind the fridge only creates air turbulence; this does not remove the heat.
VENTING is the most important issue! The below web site explains venting and provides pictures. If your venting is poor, your cooling is poor.
http://www.fridge-and-solar.net/fridge_vent.htm
“Theoretically, perfect venting will create a draft that will remove heat from the cooling unit in even the warmest conditions. However, perfect venting isn't always that easy to achieve. The purchase of an add-on fan can solve a lot of problems in border line venting, but is not a cure all for terrible venting. The important thing to remember is that the fan should be installed above the cooling unit, preferably right at the roof vent. The purpose of the fan is to improve the draft, not to blow air onto the cooling unit.”
“The venting of an RV gas/electric refrigerator should be designed to not only provide a place for the warm air from the cooling unit to escape, but designed to actually create a draft that will remove expelled heat as efficiently as possible. Poor venting can cause the cooling unit to overheat and damage the cooling unit. When the cooling unit gives off heat, it causes air around it to warm. Warm air rises causing cooler air from the lower vent to enter the area and to extract more heat from the cooling unit and also rise. The greater the difference in temperature between the warmer air and the cooler air, the faster the air will rise. Narrowing the path of the air flow forces the cooler air through the cooling unit coils as it rises.”
Above my fridge I installed a backing to “prevent dead air space” which is a cause poor ventilation. The RV MFG had a backing in place but it was 5 inches short of coverage (poor workmanship and quality control). I removed the screen from the vent and replaced it with a removable and accessible screen.
I installed two fans for maximum ventilation. Additionally, I placed a fan inside the fridge to circulate the air. Yes! It works! My fridge is much cooler, maintaining 30F to 35F consistent during a camping trip in July 2012 during 100F plus days! I can make ice and maintain cold beer!
Attached is pictures showing before and after. The pictures show no backing above the fridge and the backing I installed; the placement of the two fans; the removable/access screen; fan products, inside fridge fan and roof fan.
1. Remove the top vent cover and cut and remove the screen
2. Correct any ventilation problems
3. Install under the vent cover as instructed, using the tabs on the fan assembly, slide the assembly between the roof and vent cover securely
4. Re-attach a removable/accessible screen
5. Do not use the thermostat (thermo switch) that goes to the heat tube (the fan MFG informed me this thermostat/thermo switch does not always work) install an on/off switch in the line
6. Place battery operated fan inside the fridge
7. Total cost $70