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HOW OUR NEW FRIDGE WILL PAY FOR ITSELF IN 18 MONTHS

With my new writing gig, we’ve decided to buy a new fridge this month. Nothing fancy, just something black and in the 500-dollar range that will last a long time and use less power.

Our current fridge is 24 years old and so loud we have to unplug it each time we record our podcast or do voiceover, even with our home studio door closed. It runs too cold or not cold enough, no matter how carefully we set the dial. It uses lots of power (and yes, we do vacuum the dust out of the coils). It also pees a bit. This could warp the wooden kitchen floor.

Also, our refrigerator’s compressor motor runs constantly, which is yet another reason to replace this frosty, peeing beast. New fridges have little microchips to switch the motor off when it’s not needed.

The old fridge has done well for itself (I hope the new one will last a quarter-century), but it’s time to buy my first major appliance.

Ahhh…adulthood.

So we were wondering “how long will it take the new one to pay for itself in saved power?” To do this, we had to figure out how much power the old one is currently using.

Ever look at your power meter? It’s that thing somewhere outside your house that has little dials on it. It’s an analog steam punk-looking device that probably hasn’t changed in design in 80 years. They certainly haven’t changed since I was a kid, 40 years ago. They do make digital ones, but most of the meters in use are still the type with the moving dials.

The little vertical clock dials at the top tell you how much power (in kWh or Kilowatt hours, i.e. thousand watts per hour) it’s using over a period of time. The big horizontal silver dial below that measures power being used right NOW.

Every few months, a guy comes by your house, gets bit by your dog, and reads the meter. I wanted to do this on our domicile myself (except for the dog part).

I had to search the term “how to read a power meter” to crack the code. Most of the few results only tell you how to read the top dials. But I found ONE that told me how to read the horizontal silver dial. This is the formula:

Look on the meter for something that says “Kh X.X”, where “X.X” is some number (often 7.2). Plug your numbers into the following formula:
3.6 x Kh factor
—————– = kW
number of seconds

First I went out and looked at the meter in normal operation and familiarized myself with its mysteries. I made a friend. “Hi Mr. Meter, do you mind if I poke at you with my eyes?” He didn’t answer, and I took that as him not minding.

I watched the silver dial happily rotating, wrote down the Kh=x.x number (ours is 7.2) and headed inside.

We unplugged everything in the house. Everything except the gas stove, but we couldn’t easily move it, and all it has on when it’s not cooking is a digital clock.

I went outside. The silver dial appeared dead. No perceptible movement.

I came back inside, plugged in the fridge, waited 20 seconds for the cacophonous motor to kick on, and went outside, cell phone in hand, set to “stopwatch”.

The silver dial has a black mark at one point, so you can tell when it’s gone all the way around. With only the fridge running, the dial took 75.5 seconds to rotate once. By applying the above formula, that works out to 343 watts per hour. Multiplied by 24 hours x 365 days a year, works out to 3004680 watts per year. That means our fridge uses 3004.68 KWH per year. That’s 3 million watt hours a year.

You could just measure with a normal-day level of appliances and lights on, then unplug the fridge and subtract. But we felt more scientific comparing nothing on to only the fridge on than we would have comparing everything on to everything minus fridge.

Just for kicks, we wanted to know what we use in a normal day hanging out in the nest. We left the fridge on, plugged everything back in, and turned on two laptops, a mixer, phantom power on the mixer, powered computer speakers, two digital clocks, the cordless phone, the DVD player (set on “off”, but still using a little power). Total usage: 762 watts.

That means our old fridge eats almost half of all the power we use in a normal late afternoon when a lot things are on. And the fridge is on ALL the time, which means it uses more than half of all the power we consume.

Just for further kicks, we left all the above on and also turned on the TV, which we rarely do while all the other stuff is on, but this put the total up to 836 watts per hour.

The new fridge we just put a down payment on (a brand name-unit, well rated on Consumer Reports, $550 new, $594 with tax and delivery, on sale from a major chain outlet, and it’s Energy Star rated) uses 432 kWh per year, less than one-tenth of our old one.

According to our power bill, we pay 16.6 cents per kWh. This price can change slightly, but it doesn’t change a lot.

So, the old fridge costs $498.77 per year to operate. The new one will cost $71.71 a year to operate. This means that the new fridge will cost $427.06 less per year to run than the old one.

The energy savings will pay for the new fridge in 1.39 years, or about 18 months. AND the new one won’t pee on the floor or rattle loudly in our quiet, lovely little nest.

This entry was posted by Michael W. Dean on Sunday, October 21st, 2007 at 4:08 pm and is filed under Gear porn, Super happy fun blog!. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.