Buying a new fridge to save money— and the world

Shopping for an energy efficient fridge

On a recent visit to extended family, while eating dinner, I noticed the fridge was making quite a bit of noise – substantially more than my own fridge at home. What was more, the humming didn’t really seem to stop. Ever. (That’s not how a fridge is supposed to behave, right?)

The fridge in question, a double-door General Electric, had been in service for a long time. Possibly from before there was an energy star rating system.

But why replace a working fridge? That’s just wasteful spending, right?

Or is it?

I decided to find out. 

Cold hard numbers

I had previously been doing some experiments with smart plugs – plugs you can remotely turn on and off, some of which measure electricity use as well.

So I plugged the fridge into one (not the greatest smart plug in the market, but good enough for this experiment)*

After three days I looked at the data and found this:

Energy consumption of the old fridge
Energy consumption of the old fridge

Wow, 7.24 kWh/day on average. That’s a lot of energy for a fridge to use, even for a big one like this.
And it’s costing a lot of money! 

At 25c/kWh (average cost/kWh in NSW), that’s $1.81/day or $660/year.

A new energy efficient fridge would definitely use a lot less electricity (and be a lot cheaper to run). But how much less?

The government-run Energy Rating website has a great calculator to find out. I found a fridge of a similar size as the old one, with good test results on Choice (the Mitsubishi MR-L650EN-GSL-A2) and checked the calculator.

The calculator rates it at 395 kWh/year ($98.75 when paying 25c/kWh). That would equate to $560/year in savings compared to the old fridge.

This isn’t a cheap fridge, but with those savings it would pay for itself in a bit over 4 years. A fridge that pays for itself, imagine that!

The household purchased the fridge and to verify it delivered on its low-energy promise, I plugged it into the smart plug as well. This is the data over a 5-day period:

Energy consumption of the new, energy efficient fridge
Energy consumption of the new, energy efficient fridge

The smart plug showed energy use of 1.07 kWh/day on average, or 390 kWh/year for the new fridge. About the same as the calculator had promised.

What about the environment?

The financial case is clear. But what about the environmental one?

The energy consumed by running your fridge is only part of its environmental impact. There is a lot of energy ’embodied’ in your fridge (energy consumed while producing  and transporting the fridge).

For a full environmental impact analysis of a new fridge, you need to take this into account as well. But this kind of ’embodied energy’ data is hard to find.

The best I could find is this website, which suggests the embodied energy of a fridge is about 5900 megaJoule or about 1638kWh, the equivalent of 234 days of running the old fridge.

Therefore, environmentally the return on investment is about 5 years (and less if some bits of the old fridge are recycled).

How many fridges?

All of this made me think, how many inefficient fridges are there in Australia? What would the impact be if we replaced all of them with energy efficient ones? 

Do you have an old fridge (maybe as a second fridge or beer fridge in the garage)?

Consider plugging it into a smart plug for a few days, to see if it’s costing you (and the environment) too much and if it’s worth replacing. Or maybe you don’t even really need that second fridge in the first place.

Adriaan Stellingwerff is a Senior Software Engineer at Wattwatchers.

* Smart plugs can be a great way to augment the circuit-level data from a Wattwatchers Auditor with appliance-level data. If you don’t have a smart plug on hand, you can still get an idea of your fridge consumption by looking at the overnight consumption (when most other appliances and lights are switched off) of the circuit your fridge is on. Below is an example of what this looks like for a normally functioning fridge.

Energy consumption pattern for a normally functioning fridge
Energy consumption pattern for a normally functioning fridge