Fridge humidity

[MattS]

What humidity should you be aiming for in a fridge?

I've just replaced my old fridge compressor with a new Isotherm G80 fridge kit, which is performing well (Although not being pushed hard in the middle of winter!) - but I've noticed the humidity in the closed fridge is up at 70%ish.

Is this normal? Do others do anything to try and keep the humidity in the fridge compartment down?

 

[Spirit (of Glenans)]

Warm air contains much more water vapour than cold air ( the mixing of the two, on a large scale, is why we get rain and fog). Either your fridge is not working, or you are allowing warm air from the saloon to enter the fridge, then measuring the humidity of the result.

 

[William_H]

As said in a different way, humidity percent is a measure of the moisture in the air as related to the maximum amount of moisture the air can hold. (before falling out as dew)
So air at 20 degrees can hold a huge amount of moisture without seeming humid because there is a lot more capacity to accept more moisture. (low humidity%) if you take that exact same block of air and cool it, as in a fridge the air's capacity to hold moisture falls to the point where it becomes 100% humidity. I would say do not worry about humidity % in fridge if it were too low it would dry out food too much. ol'will

 

[geem]

Humidity measurement in a fridge is pretty irrelevant. Any moisture will condense on the evaporator plate and freeze. If you open the fridge door a lot you will grow your ice moster pretty quickly. If you have the fridge set quite warm you will likely get moisture dripping off the evaporator plate.

 

[MattS]

Thanks - that's helpful! And thanks for that explanation @William_H - that makes sense!

 

[luke collins]

That’s normal RH. In fact the higher the better so the closer the evap plate temp to the air temp the less moisture removal from the air. The reason for designing with high RH is so not to dry out products ie veg and fruit that contain lots of moisture. Does not affect beer and tins so most boaters are fine.

 

[MattS]

Thanks @luke collins - helpful.

 

[geem]

That’s normal RH. In fact the higher the better so the closer the evap plate temp to the air temp the less moisture removal from the air. The reason for designing with high RH is so not to dry out products ie veg and fruit that contain lots of moisture. Does not affect beer and tins so most boaters are fine.

We have a seperate 'warm' fridge for fruit and veg. We keep it at about 9degC. This seems to be a good average temperature for most fruit and veg to maximise the life. The main fridge has a 10 litre freezer inside it. This fridge gets down to about 2degC at the bottom and about 4 at the top. Nice cold beer at the bottom. It's our storage for anything but fruit and veg that deteriorate at the lower temperatures

 

[MattS]

I don’t quite have the space for 2 fridges unfortunately ? mine’s a fairly small converted cool box on a 28ft boat. Reasonably good insulation, but I wouldn’t say amazing - internal temp seems fairly responsive to the outside ambient temp. Have recently installed a new Isotherm GE80 kit which is obviously working much better.

I’m reading 2.5C on the bottom and 4.5-6C at the top of the compartment at the mo