Turn Freezer off at Night?

QrizB

JohnSwift10 said:

One of my neighbours has their upright freezer in their garage and he has bought a plug in timer and set it to switch the freezer off from midnight to 08:00 hours.
Anyone have any idea if he will save any electricity?

I don't think he'll save any appreciable amount of electricity, certainly not enough to recover the cost of the timer.
And he risks shortening the life of his freezer.

Benny2020

Keeping the freezer full should help.

Ultrasonic

EssexHebridean said:

Ultrasonic said:

EssexHebridean said:

If he really wants to save energy then moving the freezer into the house would possibly do so.

Why do you say this? I'd expect the garage to be better as it's colder?

Going back to the original question, freezer manufacturers obviously do their best to optimise efficiency. If it would save electricity to not actively cool overnight they do this already.

I believe the theory here is that modern fridges and freezers are optimised to work best at “normal indoor” temperatures and at temperatures above or below those they are less energy efficient. Don’t ask me about the physics behind that though! I know my parents were warned that by having their freezer in the (brick built, insulated but not heated) shed  they would potentially find that it used more energy AND might have a shortened lifespan, though.

This article gives some info. that at least sounds plausible to me (I'm a physicist as it happens but not a freezer specialist!)

https://garagetransformed.com/freezer-in-garage/

Verdigris

Very marginal saving, possibly. Little risk of food poisoning.

I had a freezer break down, a couple of years ago, and couldn't get a replacement for about a week. I was amazed how little food I had to chuck away, and most of that was stuff I should have chucked out anyway, if I kept better order. Despite opening the freezer, numerous times, to get stuff out to eat, everything left was still frozen when the new freezer arrived. It may not have been at minus 18 but it was certainly sub-zero.

I have not died of, or indeed suffered, from food poisoning, in the interim.

markin

The are special freezers for out doors, most others will say that they are best at 18c and must not be below 0c

BobT36

I don't think he'll get food poisoning or anything just after a few hours but....eh, freezers only run when they need to anyway, you can literally hear it turn on...

Simply use an Owl electricity monitor and see how much it changes between being auto on/off and switched on / off.

prowla

Is the freezer permanently on anyway or does it just kick in when the temperature fluctuates?

BikingBud

EssexHebridean said:

I’d hazard a guess that a modern freezer will see almost no temperature drop internally overnight with power removed - certainly at this time of year. Whether it will make any appreciable difference to the energy use is another question, but is he going to kill himself with food poisoning? Almost certainly not! 

If he really wants to save energy then moving the freezer into the house would possibly do so. (Or alternatively, on an Economy 7 rate, turn the thing off for the final 8 hours of the peak rate!)

No temp raise = no requirement for refrigeration cycle = no energy req.

Plugged in/switched on/switched off = no difference

If the temp is rising then potential degradation to stored food may occur and should be assessed as food hygiene risk.

Alternatively go old school, dig hole in garden and wrap food in wet cloths - Job jobbed.

Norman_Castle

I'd expect a freezer would only run when its thermostat tells it to so it'll either run when needed overnight or when switched back on the morning. The cost would be the same.

How does the cost of running a mechanical timer, 24h @ 1.5w compare to the compressor occasionally firing overnight?

If well insulated could money be saved by only running on cheaper overnight electricity?

I've got a fridge with a small freezer. I also had a very small freezer which cost £30 per year to run. For me it was cheaper not to store so much frozen food although this does depend on personal circumstances.

Petriix

There's definitely something in the TOU idea. My fridge freezer is quite power hungry. I wish it would run in its lowest power state during peak hours, then run its high powered defrost cycle followed by a super cool in the off peak window.

I occasionally switch it off for a brief period if I happen to notice it's consuming lots of power at an inopportune time - say I'm running a high power appliance off surplus solar but the fridge is drawing 300W, pushing us into importing peak grid power; then I turn it back on again once we're back in surplus. I'm really looking forward to getting a battery installed so that it can take care of such fluctuations!