Monday 6 October 2014

Can a fridge and an oven be good neighbours?

Surprisingly, the answer seems to be yes. In our kitchen the oven and fridge are built in side by side. The oven is a gas fan oven and as well as the fan in the oven it has a case fan which is supposed to keep the case cool, so it should not be heating the fridge too much. However, I have never been entirely convinced that having them next to each other is a good idea. Being temporarily in the possession of some electricity consumption loggers I monitored the electricity used by our fridge and oven, and the fridge temperature, over a day when we used the oven to cook a roast dinner. The charts below show what happened.
Main findings:

  • The fridge temperature did not exceed normal bounds.
  • The fridge worked a bit harder during the period when the oven was on and shortly afterwards: 21W on average compared to 16W the rest of the time.
  • In total, the fridge used an extra 0.03 kWh (1 kWh costs about 14p). 
  • The oven used an extra 0.26 kWh - 8 times as much as the fridge.

Oven power consumption, fridge power consumption and fridge temperature at one minute intervals over almost a day, when the oven was used to cook a roast dinner. The yellow section shows the oven being used, and the period afterwards when it was cooling down. The oven is a gas oven, and the electricity is used mainly for fans.
The bottom two strips on the chart are the fridge temperature and power consumption. The temperature logger only reads to 0.5C so that graph is rather jaggy. The fridge temperature varies between 4C and 7C. When it hits 7C the compressor starts working (middle strip) and cools the fridge down. When it hits about 4.5C the compressor stops and the fridge slowly warms up again.

When the oven was on there was no obvious difference in the fridge performance. Importantly, the temperature did not rise above 7C. However, on the next fridge cycle the fridge seemed to warm up more quickly and take longer to cool down. It looks as though the case fan is effective while the oven is on but afterwards it shuts off before the heat has fully dissipated which means the fridge has to work harder for a while.

I am no longer concerned about having these two next to each other, especially as we don't use the oven very much.

By the way, we fitted out this kitchen in 2000. It never occurred to me then that a gas oven would use significant power at all.  However it takes 5.4W all the time, just to run its internal computer and digital display - about £6/year. When we eventually get a new one it will be covered by the EU regulations for standby power consumption and will use less than 1W.

Does anyone have any suggestions for what I could do with these electricity loggers? I am sure I will have to give them back soon.


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  3. Great article.


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