American Fridge Freezer - doing the maths

Xbigman

I think you need to take the energy ratings, in particular the estimated kwh usage, with a big pinch of salt. They are a guide to different appliances and not an absolute.

Here are some numbers that might prove informative.

The story so far. I've mentioned on other threads that I had a fridge freezer with a small microwave sized freezer compartment as well as 2 small under the counter freezers but back in January I turned off one of the freezers, junked the FF and bought a table top fridge.
The alleged energy ratings are:
Fridge freezer  217 kwh per year.
Freezer 1          210
Freezer 2          210
Fridge               100

So I went from 637 kwh per year to 310, according to the energy ratings. 

Last week I decided to test this and I dug out the FF from the garage and just about managed to squash all the frozen food into the little freezer compartment. I wanted to do a test with my energy monitor over 4 days to see how the two set ups compared. 
Day one with the FF had to be ignored because with the FF on setting 1 (of 7) the fridge temperature was 10c. I ended up with it set on 6 to get the fridge down to 4c. So over 3 days it worked out at an annual usage of 269 kwh. Well over the 217 alleged usage.
I then tested the separate fridge and freezer (on an extension lead so their figures are combined) both set on the minimum settings and over 4 days they consumed energy at an annual rate of 235 kwh. Significantly under the annual estimate and cheaper than the FF. The FF is now back in the garage. 

The FF is about 5 years old, the freezer is 3 years old and the fridge is 8 months old. We are not talking decades old equipment that is failing here. 
Be careful what you set fridges and freezers on because it makes a huge difference to usage. Buy a cheap thermometer and put it in the fridge so you can check its working right. Defrost regularly.



Darren

PS Talking of my energy monitor. My usage has crept up by about 1.5 to 2 kwh per week over the last month without any change in my habits. I've finally tracked this down. My computer draws about 60 watts normally but about a month ago I started playing Empire: total war. This is much more graphics intensive than the other things I use my computer for and I had my energy monitor plug on it this morning and whilst playing it registered 110 watts draw (the draw figure was jumping about quite a bit 110 was about average). So 50 extra watts for 4 hours a day average (yes really) explains the extra usage. 
And it also draws 5 watts an hour when turned off (that's off, not standby or sleep mode), which is why I always turn it off at the plug.

xeny

Xbigman said:

And it also draws 5 watts an hour when turned off (that's off, not standby or sleep mode), which is why I always turn it off at the plug.

As a tip - a watt is a per second measure, so you just say it draws 5 watts which means it uses 5 Wh in an hour, or 1KWh in 200 hours (5*200=1000). If you poke around in the BIOS there is almost certainly a way of reducing those 5W to nearly nothing -look for wake on lan settings or on some motherboards there is a setting called ErP - see https://forums.tomshardware.com/threads/what-exaclty-is-erp-in-bios.2289200/