covering fridge vent when switching to compressor type refrigerator

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Billy D.

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Dec 9, 2015
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My Norcold three way fridge is dead and I?m going to switch to a compressor fridge.
I won?t be needing the lower vent anymore, and it leaks when it rains, so I want to cover the hole. I was thinking of a large square piece of 1/4" thick PVC sheet sealed to the outside of the coach with butyl putty and some stainless screws. The coach is fiberglass/gelcoated.

Any recommendations?
What do others do to blank off their fridge vents when switching to compressor type?

Thanks!
 
Lots of alternatives. I'm thinking I will keep the old vent panel but close the grill portion with fiberglass cloth (roving) and epoxy. My fridge vent is three-color  match for the coach paint scheme, so I want to preserve it. I've seen real siple solutions too, basically duct tape over the openings (applied from the inside, for cosmetic reasons).

Don't ignore the roof vent. It may keep water out, but you probably don't want hot/cold air entering that way either.
 
Before completely closing off the vent openings, consider that a residential compressor fridge also generates heat that needs some place to go besides inside the RV. In hot weather, having at least the fridge roof vent open will help reduce the load on the A/C system. I also leave one of the lower vent strips open in warm weather to allow some convection cooling behind the fridge. If your fridge is vented to the inside of your RV at the bottom, then there isn't much you can do, but it still needs an air source at the back to facilitate the heat transfer.
 
Thanks for the responses, guys.

I?m going to be installing a small dorm style fridge, probably 4 cu ft maximum, so I don?t expect to be generating too much heat. Maybe that?s wishful thinking, though? Some sort of convection might be in order. I?m just eager to delete the lower vent because it has been a cause of persistent water intrusion, and it?s yellowed an unsightly.

I plan on retaining the upper fridge vent even though it?s a mouse paradise. :(
 
Dutch is correct. Looking at my own fridge it wouldn't have sufficient rear ventilation to work properly. Knowing enough about refrigeration, I know that insufficient air circulation will over work and shorten the life of a residential refrigerator. Caulk up the leaks and leave one slot open on the sidewall vent. You could also remove the roof vent cover and reduce the opening there as well, then replace the cover. End result is an aesthetically pleasing functional modification.

You posted while I was typing. If the dorm size fridge has a couple inches clearance behind it and the space it goes into is taller than it and you don't intend to close off the the space above it, it will probably have enough air circulation. You might want to remove the roof vent cover and seal that up, then replace the cover. That way you don't have a chimney sucking heat or AC out of your rig, not to mention access for insects and rodents. You would basically have an open window with a fridge that doesn't fill the original space.

Bill
 
Put a piece of metal screen in the roof vent opening to keep mice and other critters out.  It will reduce the efficiency of the vent but you'd do the same thing by blocking part of it off.
 
Don't forget that you need to occasionally clean the dust bunnies out of the heat exchanger of a residential refer.  Some have an access panel in front (good choice) and others have it in the rear.

I clean mine at least twice a year.  But I have two fur kids, aka shed-o-matics, who make it necessary.
 
You guys have some great ideas! Thanks. A few things for me to consider still.

Good tip about the dust bunnies? I have a Golden too. He?s 110 lbs and hairy. VERY hairy. He looks exactly like your avatar. Great dogs.
 
A residential fridge is designed to vent internally, usually with air flow underneath, up the back, and out the front at  the top. Some do it all at the bottom, and a few shed heat via the sidewalls instead. Best to follow the fridge manufacturers installation specs for clearances.

in my opinion outside venting is bad news unless you have sealed the entire fridge surround and vent solely with outside air. If not sealed from the interior of the RV, you get heat in the summer, cold in the winter, and bugs or critters all the time.
 
Gary, you must have seen fridges with the coils on the back? And our new Haier fridge has enclosed coils on the bottom that vent out the back. There is no front vent, and the cabinet is completely sealed from the interior around its perimeter. The fridge heat adds no A/C load in hot weather, although it might be nice to have that heat load inside in the winter.
 
Samsung RF18 says to maintain 2 inches clearance around sides and back for ventilation.
 
Billy D. said:
You guys have some great ideas! Thanks. A few things for me to consider still.

Good tip about the dust bunnies? I have a Golden too. He?s 110 lbs and hairy. VERY hairy. He looks exactly like your avatar. Great dogs.
Click to expand...

We have two.  The one in the picture is a petite little girl at only 63 pounds.  Out other girl is 75.  They have elevated shedding to an art form.
 
and the cabinet is completely sealed from the interior around its perimeter.
Click to expand...

That's the key. RV fridges are designed to be sealed around the edges of the cabinet, which allows for their external venting. Residential fridges are not designed to be installed that way, but you can do so if you take time to understand how it disposes of its excess heat.  The key is that there has to be air flow, an inlet source and a place for it to go. You should not have the inlet inside and the exhaust outside, unless you want to leave a window open to complete the circulation path. You can't continually suck air out of the interior unless there is some way for air to get back in (but maybe there are enough air leaks to do that). Lack of good circulation will result in fridge cooling problems and shorter compressor life. Symptoms of that could be anywhere from minor erratic cooling to a major early life failure.

I'm pretty sure your Haier manual contains this warning - all that I have seen have it:

This refrigerator should not be recessed or built-in an enclosed cabinet. It is designed for freestanding installation only.
Click to expand...

The 12.2 cu ft Haier specifies these free-space requirements:

Sides: 3/4"
Top: 1"
Back: 1"


Yeah, I remember the coils on the back. It's oldtime tech and rarely, if ever, seen on a recent model fridge.
 
Gary RV Roamer said:
That's the key. RV fridges are designed to be sealed around the edges of the cabinet, which allows for their external venting. Residential fridges are not designed to be installed that way, but you can do so if you take time to understand how it disposes of its excess heat.  The key is that there has to be air flow, an inlet source and a place for it to go. You should not have the inlet inside and the exhaust outside, unless you want to leave a window open to complete the circulation path. You can't continually suck air out of the interior unless there is some way for air to get back in (but maybe there are enough air leaks to do that). Lack of good circulation will result in fridge cooling problems and shorter compressor life. Symptoms of that could be anywhere from minor erratic cooling to a major early life failure.

I'm pretty sure your Haier manual contains this warning - all that I have seen have it:

The 12.2 cu ft Haier specifies these free-space requirements:

Sides: 3/4"
Top: 1"
Back: 1"


Yeah, I remember the coils on the back. It's oldtime tech and rarely, if ever, seen on a recent model fridge.
Click to expand...

Our Haier 10 cu ft manual says:

"The following are recommended clearances around the refrigerator:

Sides...... 1"  Top...... 1"  Back...... 2"

Of course we have much more than the recommended 2" behind the fridge, and with the roof vent open, there's no need for the side or top clearances to dissipate the heat from the rear fridge opening to the compressor and coils. Air for circulation comes in through the single open section of the standard three slot RV fridge vent cover at the bottom of the cavity. In really cold weather, I do close off the bottom vent completely to keep the fridge within its optimum operating temperature range though.

 
I'm not familiar with your Haier and yield to your judgment on the venting for it, but some [many?] fridges absolutely require air flow underneath. The Whirlpool in our stick house, for example, has the sole radiator underneath and does not shed any heat at all via the rear wall. Air has to flow in underneath and then rises at the back to escape at the top.  Our U-line under-cabinet icemaker/fridge is much the same except it has a fan that pushes the heated air back out the front.

The GE & Hotpoint (essentially identical) models I am looking at for the coach also appear to have their heat exchanger underneath, but I haven't gotten a definitive answer on those yet. The back walls are smooth and flat, with no fins and no air openings.
 
You guys are really helpful. Thanks! Couple questions, if you don’t mind…

My 4 cu ft Norcold was plenty big enough for us, and I’ll probably be looking for something in that size range in a 110V compressor fridge. Is the heat generated by a smaller fridge notably less than a larger fridge? Say 4 cu ft versus 10 cu ft?

I’d prefer to not vent it to the outside at all because I’d love to seal off the existing vents. I’d prefer to just go with the recommended cabinet clearances. But I’d have to rethink that if it generates “a lot” of heat. I’m sure it’s impossible to quantify, but how much heat are we really talking about? My coach is a small 21 ft class C, if that helps.

Also, I’ll likely be using an inverter, which will create even more heat. (I know the inverter approach is less efficient and creates more heat than using a DC compressor fridge, but AC refrigerators are much cheaper and that will allow me to budget a lot more for my upcoming solar setup).

Any thoughts or opinions are greatly appreciated!
 
When we lived in a sticks and bricks house, the kitchen floor was ceramic tile. The cats, dog and our bare feet knew that the floor in front of the fridge was comfy warm in the winter. The heat exchanger was underneath the fridge, not on the back. AS far as the question, whether a smaller fridge puts out more heat or not, an educated guess would be less heat. Everything would be smaller, the compressor, the heat exchanger and the space it has to cool.

Bill
 
I don't think you have to worry about the amount of heat generated by a compressor type refrigerator.

Both absorption and compressor refrigerators remove the same amount of heat from the box, the difference is an absorption fridge has to start with several hundred watts worth of heat to run the cooling process.  This heat, along with the heat removed from the interior, has to be dissipated outside the refrigerator.

A compressor fridge only uses about 50-70 watts to run it's compressor, so it produces much less waste heat.

You still have to provide airflow to dissipate the heat, but it's not enough to materially raise the temperature of an RV's interior.
 
Agree with Lou - the heat comes primarily from heat removal from the inside of the box. The modern compressors are highly efficient and don't waste much heat (watts). Plus,  "Energy Star" fridges are also well-insulated so that the compressor doesn't have to run much, reducing the heat exchange workload. As long as you don't keep the door open a lot, there isn't all that much heat to shed.
 
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