Lately with the help of the monthly reports, I’ve seen my average wattage increasing. I have not increased my usage on anything. In fact I’m always looking at cutting more. Through using the app I already knew my fridge accounts for 39% to 54% of my monthly bill. That is where I started to dive a bit deeper…
In the app I flipped through the different months and noticed a trend of increasing use. Here it is summarized.
Comparing a lower month - February, with a higher use month - June, it’s becoming shocking!
Unfortunately I can’t show even worse months July and August because total time on is not displayed.
So, I was wondering, it this type of increase typical during hotter months, because it actually is hotter in the house? That would make sense. I don’t have A/C, but it really hasn’t got much hotter than 85 degrees inside.
Or does this mean the fridge is failing and having to work harder? I’ve looked at new fridges and their estimated annual use is usually less than 700 kWh.
That’s normal and expected. It takes more energy to move heat as the delta T increases.
Check your coils to make sure they’re clean anyway. They can get caked up with dust and junk pretty quickly, especially if your fridge pulls air in from the floor.
A quick analysis of my home comparing Fridge energy usage vs Kitchen Temperature (via Ecobee sensor). At first blush, it appears that there is a positive correlation between average Kitchen temperature and detected Fridge energy usage per day. I have two Sense-detected Fridge devices (but actually 4 fridges so the detected ones might represent some conflation). My kitchen is air conditioned so the temp range is narrower than yours, plus my daily Fridge usage is far more variable… Here’s the daily average Kitchen temp vs. Energy usage (kWh) for each detected fridge since April 2019 - no changes in Fridge thermostat settings over that time.
But if I look at the data on monthly level, something more complicated is going on. Some months for Fridge 2 (June and July 19) are negatively correlated with temperature. We were traveling, so the thermostat went up to the “away” mode ceiling and we opened the fridge door far less frequently. And many months appear flat. Fridge 1 had very little energy usage for 2nd half of December (travel again ?), and the thermostat dropped to the low “away” value causing a steep fitting line.
There is another explanation for higher usage during the summer. Summer comes with not only higher temperatures but also higher humidity, at least where I live. The refrigerator has to remove whatever moisture enters when the door is open, and that moisture has something called latent heat. Removing the latent heat makes the fridge work harder.
My correlation, without looking at the data too hard, is negative.
Why?
Summer: AC keep kitchen quite cool. We drink room-temp water & tea vs iced water & beer. Occasional homemade popsicles but ice cream is pretty much banned. Bottom freezer helps with frozen peas extraction efficiency.
Winter: radiant floor keeps kitchen quite warm. We bake a lot more in winter ==> warmer kitchen. Small apartment.
There’s another odd correlation to consider: If your house (and so fridge) are solar powered then summer is likely the “cheaper” time to be cooling. In the future we will all have massive freezers making ice batteries throughout summer! No?
As many have mentioned already, I’d definitely expect this to be the case @Kevin_K.
I’m going to take a shot at this - heat exchange is a primary function of the coils on a refrigerator. If the external temperature is high, that requires the compressor to run more to regulate the internal temperature, increasing how often your refrigerator is cycling on.
We actually did a deep-dive into refrigerators in a blog last month. The beginning is a historical look at refrigerators, but it gets into the functionalities and how the energy usage of a refrigerator increases over time.
Thanks @kevin1 for your “quick” analysis! Based upon everything I’ve read, it will just be a seasonal increase. Still…I may be guilty of having never-ever cleaned the coils.
It has been on my home task list for MANY months. @JustinAtSense is there a “Research project” for clogged/dirty refrigerator coils??? I could be the first participant!!!
