What temp should a fridge be at?

[GreenHeaven]

The new Isotherm digital display has an adjustable range presuming I know what temp i want my fridge at...

[paulajayne]

Fridge between 0 and 5 degrees Centigrade
Freezer -18 Centigrade and colder.

Aim for circa 4 on the fridge and -18 on freezer.

Colder is more power usage.

[Rumrace]

Someone told me to keep them full of water bottles so the don’t try to chill air as you empty their contents. I’ve also read the preset from the factory is too high on most. ????

[rslifkin]

A full fridge will cycle more slowly and hold temperature more consistently, so it will work a little better and be more efficient. But as long as there's enough stuff in there, it doesn't need to be totally full.



In general, 35 - 38* F is a good range for a fridge. Definitely no warmer than 40* F. 0 - 10* F for a freezer. Freezer temps can be a little warmer, but it won't keep ice cream hard and you won't be able to store meat, etc. for as long as you can at lower temps.

[GreenHeaven]

Originally Posted by paulajayne

Fridge between 0 and 5 degrees Centigrade
Freezer -18 Centigrade and colder.

Aim for circa 4 on the fridge and -18 on freezer.

Colder is more power usage.

Impossible. in 34c this thing cant even get below 15c running day and night

[HankOnthewater]

Originally Posted by GreenHeaven

Impossible. in 34c this thing cant even get below 15c running day and night

I agree with paulajayne's suggested temperatures. I must say i select the temps in celcius at -15 for freezer, and 6 degrees for the fridge, just to save a little on electricity consumption.

If can you only cool the fridge to 15 degrees celcius, then I think your fridge may not be working properly. Is the compressor running fulltime? If not, then your temperature reader might be faulty.

[rslifkin]

Originally Posted by GreenHeaven

Impossible. in 34c this thing cant even get below 15c running day and night

If that's as cold as you can get, the fridge isn't working properly or is just inadequate for hot weather. 40* F / 4.5* C is the upper limit for safe food storage in a fridge for more than a few hours.

[sailingharry]

As a functional balance between energy consumption and ideal temperatures, we run our freezer at about 15F (-9C) and our fridge at about 37F (2-3C). Refrigerated foodstuffs seem to last plenty long, and freezer food stuff definitely lasts a couple of months. It makes ice cubes just fine, and ice cream is pleasantly firm. We can lower the temperatures, but that of course consumes more power.

Our unit, a Sea Frost, has an adjustable expansion valve. Adjusting that dramatically improved my ability to reach low temperatures in the freezer.

Low Freon charge can result in poor functionality. But the only way to have that is a leak, which is fairly unusual. And correctly charging marine refrigeration units is very delicate. In fact, about the only way to effectively do it is to completely drain it, and then recharge with a scale to provide the correct weight of freon.

[s/v Jedi]

We have experimented with temperatures for many years. Accepting a higher temperature means food spoils sooner, so there is no free lunch

My recommendation still allows frozen food to keep for 6 months. A vacuum packed beef tenderloin looks and tastes as good as fresh after 6 months in the freezer. Vacuum packing is the key, can’t skip that.

So we use 5 degrees Celsius for the fridge and -14 degrees Celsius for the freezer. When the freezer is tuned well (correct refrigerant charge for climate you’re in) it can still keep a 50% duty cycle in the tropics.

Fridge power consumption is for the most part dependent on the number of times it is opened during the day and how many warm items are placed in it.

[rslifkin]

Originally Posted by sailingharry

As a functional balance between energy consumption and ideal temperatures, we run our freezer at about 15F (-9C) and our fridge at about 37F (2-3C). Refrigerated foodstuffs seem to last plenty long, and freezer food stuff definitely lasts a couple of months. It makes ice cubes just fine, and ice cream is pleasantly firm. We can lower the temperatures, but that of course consumes more power.

Our unit, a Sea Frost, has an adjustable expansion valve. Adjusting that dramatically improved my ability to reach low temperatures in the freezer.

Low Freon charge can result in poor functionality. But the only way to have that is a leak, which is fairly unusual. And correctly charging marine refrigeration units is very delicate. In fact, about the only way to effectively do it is to completely drain it, and then recharge with a scale to provide the correct weight of freon.

I'd call that a pretty much perfect fridge temp. And a good compromise for the freezer, as most of us don't keep things in a boat freezer as long as we might in a house. So at 15* F things will still last plenty long enough, just not quite forever like that might at 0* F or colder.

[wingssail]

Originally Posted by GreenHeaven

Impossible. in 34c this thing cant even get below 15c running day and night

I'd guess that you either have too large of a box, poor insulation, or low freon.

(and the water temp is more important than the air temp).

Our small box with 5" insulation and using the lowest price, simplest, air cooled Dometic ice box conversion unit keeps a temperatures of 35F and 9F in the freezer which is cold enough for meat to stay solidly frozen indefinitely and the critical requirement of making ice cubes. Ice cream is not an issue because any container of ice cream which is not consumed instantly upon opening is too big to fit in the freezer anyhow.

Our unit uses about 50Ah in a 24 hour day in 90F degree days with 72F degree sea water surrounding the boat.

[wingssail]

Originally Posted by sailingharry

...Low Freon charge can result in poor functionality. But the only way to have that is a leak, which is fairly unusual. And correctly charging marine refrigeration units is very delicate. In fact, about the only way to effectively do it is to completely drain it, and then recharge with a scale to provide the correct weight of freon.

Sailing Harry, slow freon leaks are common especially with owner installed units. We've had them and others I know have come back to their boats after a long absence have found their refrigerators need recharging.

Recharging is not rocket science. After paying a technician a couple of times I decided to do it myself. I brought an inexpensive set of hoses and gauges and a bottle of refrigerant at an auto supply store. You just attach the hose and inject a squirt of gas. It usually takes very little to restore full performance. To much gas and it does not work so you let little amounts out until it works well. I've done it twice in five years and since I snugged down my fittings two years ago it has had no further leaks. You can search for leaks by feeling the hoses and fittings. They will be oily if leaking.

A couple of people I know have punctured the evaporator plates with sharp knives and I've seen that fixed by external application of epoxy on the leak.

[sailjumanji]

We've installed the ITC on both our Isotherm CL130 Elegance upright refrigerator, and our Isotherm in-counter freezer. Several things to note. First, you need to calibrate the thermostat on the ITC. I found the easiest way is one of the small bluetooth units that records and plots temp, that you can leave in the unit. There is an app to download the data so you don't have to open the door. This makes calibration very easy.

Note that the setpoint on the ITC is the temp that you want it to reach and turn off. For instance, we set our refrigerator to turn off compressor at 35 deg. It then rises to 40 deg F (5 deg F higher), and then the compressor comes back on. We set the freezer at 16 deg F, and it has the same range and compressor comes back on at 21 deg F. I don't remember which one we purchased, but it was relatively inexpensive and access thru an app on your phone. This also measures and graphs humidity, and as such makes it super easy to determine how much your unit is cycling.

After setup, both of the ITC units we have worked quite well. It lets my wife know exact temp inside each box without having to open the door to see a thermometer. Plus the Isotherm CL130 had a design issue whereas the thermostat was located on the bottom of the freezer cold plate/compartment. When ice started to form, it would encase the thermometer. As such, the thermometer was at a colder temp than the interior. The ITC thermometer is mounted lower, and on the back wall. So it measures air temp regardless of how much cold plate frosting there is.

Word of caution. Isotherm recommended that we mount the ITC thermostat for the freezer above the food level. And in the fridge, leave air space around it. Otherwise the thermostat does a very good job of measuring the temp of whatever you have leaned against it! Like a warm beer, or fish you are trying to freeze!

We've used two of the ITC's for about two years, without any failures. Oh, and as for temperature, our freezer box can get down to a 12 deg F set point, but we found that the 16 deg F had it running much less and everything is still frozen solid. (That pic is of our fridge when were shoving off on a four month cruise!) The upright fridge is much less efficient, and needs good air exchange to achieve the 35 deg F. If we shut up the boat, the saloon gets very hot and the fridge will run continuously at around 37 deg, and sometimes as hot as 39 deg F. Internal temp in the saloon gets over 100 deg F.