Inefficient Appliances - Replace them or add more solar?

[Dave911]

I have a 90's era 17 cu ft upright freezer. I have replaced some of the controls over the years. The freezer just keeps running. It's been powered since about 1990.
So about 35 years. The compressor and fans are original and still work well. It's a very simple unit. No electronics of any kind.

The freezer isn't nearly as efficient as a newer model.

This old freezer likely uses about 1700 KWHR per year / 4.7 kwhr per day / $0.82 per day at my current power cost. (This via monitoring it with a Kill-a-watt device)
New freezers are in the 500 KWHR per year range / 1.37 kwhr per day / $0.24 per day

A new freezer, the same size, costs about $850

If I was to stay on the grid entirely, a new freezer would pay for itself in about 4 years.

I believe my entire solar system will pay for itself in 4-5 years (it's in progress).

So the payback for solar is about the same as the payback for replacing the freezer.

However, the newer freezers seem to have a much shorter life. 8-10 years maybe?

So the question is:
If I have sufficient solar capacity to cover most of my needs, do I care much about less efficient appliances?

I will be using the grid for backup power when the sun doesn't shine and for some heavy shop loads that I don't want to deal with (welders, big compressor, etc)

If I take the $850 I was planning on spending on the new Freezer, and instead spend it on more solar capacity/battery, etc, I feel like I will be further ahead.

What do you think?

 

[ctid]

Great question! And one I have been toying with. I have an upright freezer circa 1995 and a chest freezer circa 1993. With their poor efficiency, it means my overnight load is around 550w per hour, with nothing else on in the house other than a laptop charger and internet router. Using my sums, it will take too long to pay for 2 new appliances, and the new appliances will probably fail not long after they are paid for! So my plan is to wait for my old appliances to fail, probably either compressor, gas or seals, and then replace. So I have used some of the money to buy another mppt in preparation of expanding my panels.

What I have replaced is my old 250L 3kw water heater, circa 2000. It was working fine but is eye wateringly inefficient. I have bought a new 200L model with a built in heat pump. It was 1,000 Euro and with my calculations, will be paid for in less than 2 years.

 

[Brucey]

To me for an always on appliance like a freezer it makes sense to upgrade. 3.3kWh per day is a big chunk at least for me.

 

[Tulex]

"Will pay for itself in 4 years."
About how long today's appliances last.

Personally, I would replace appliances that are hard on the inverter/really high draw. So, maybe swap out an old well pump for a low draw/soft start pump, replace an electric water heater for a heat pump water heater, and move from electric dryer to heat pump dryer. Other stuff, I'd Tim Taylor the heck out of my solar system to cover it.

 

[SunDave]

"Will pay for itself in 4 years."
About how long today's appliances last.

That's the trick. The new freezer won't last 35 years, so you have to start factoring in the replacement cycle costs. If it still makes sense after that, and you don't mind the effort, then go for it. And you may get 10+ years. So on paper, it looks like it should work.

 

[OhYou_]

what style is the condenser unit, is it built into one of the walls, or is it just chilling under it by the compressor?
if it's external, under the compressor, you can add a fan which comes on while the unit is running and helps cool the condenser, then glue down EPS or similar foam to all four walls and lid to raise the insulation factor, additionally try to source a new lid gasket.

If its built into the wall then meh

 

[doing it different]

What I have replaced is my old 250L 3kw water heater, circa 2000. It was working fine but is eye wateringly inefficient.

Any type of resistive heating is hard to get more efficient. Like a dryer, or hot water tank. That is not heatpump type.

Freezer and fridges. That can be a hard one... for me if it works don't touch it.

You probably could make it more efficient especially fridges by cleaning the coils, those bottom coils get so full of dust it's crazy. A bigger fan would help. They really should have a reversing fan. Even out door heat pumps.... construction equipment often reverse the fans every so often to keep the roads clean. I think certain appliances could really benefit.

 

[SparkyJJO]

If the question is "should I do X or add more solar" the answer ALWAYS is add more solar

 

[billvon]

If you also air condition that space, then going to a more efficient freezer will benefit you twice. Less A/C needed AND less energy for the freezer.

 

[45North]

Replace the freezer. It's time and it's the right thing to do.

 

[Supervstech]

Solid freezers are incredibly long lasting.
Look at the seals, look at the wall thickness.
A 1" foam insulation layer properly applied to the door, the walls, and top will make a big improvement, most upright freezers have a heating element in the door area to keep frost at bay.
Disable that and manually defrost to save energy with the nigh indestructible unit.

Modern units benefit from newer insulation requirements, and slightly more efficient components, and computerized everything.

Electronics that are frequently clocked to fail at 10 years...

I still rock my 70s over under gold fridge...
I know a customer of mine still rocking a 30's kelvinator...

You could also source an inverter compressor upgrade kit...
Probably as expensive as a new model...

 

[SplitUniverse]

Freezer $850, panels $200 a piece or about $.50 per watt, let's say even $0.85 per watt somewhere local.
If you can add 1000 watts of solar (assuming you can just add those to your current equipment) then definitely add the solar. At about 4 hours of sun per day average you will be way ahead in the long term. and those old freezers / refrigerators just keep on going, unlike the new ones where you might come home from a vacation to find a house that you can't get the stink out of and a large puddle of water in the middle of your kitchen.

 

[SparkyJJO]

Replace the freezer. It's time and it's the right thing to do.

Care to explain more? Why is it the "right" thing?

 

[Hedges]

Reliability has an Efficiency all its own.

 

[grebaba]

Dad bought one of my freezer's in or around 1960, No self defrost, will hold a whole beef.
Still works great and I really don't care how much electricty it use's. I will never find a new one as well made as this one.
Greg

 

[SparkyJJO]

Reliability has an Efficiency all its own.

I hate replacing appliances every 5 years because they're crap. Any energy savings $ is out the window at that rate, not to mention the resource waste.

 

[time2roll]

Many do without a separate freezer. I would try to just phase it out.

 

[SunDave]

One other thought. Your measurement of your old freezer was a real-world measurement of energy use, and the new one is the best-case number that the manufacturer could use to satisfy that specific rating. There is always the possibility that the difference will not be that great. Or it's even better.

One thing is for sure. It is not clear.

 

[Citlalatonac]

It also kinda depends on heating vs. cooling days where you are. The waste heat means you either need to pay extra to cool the difference or are able to use the excess heat anyways.

In theory if you for some reason never need to cool and have resistive electric heat, then there would be no savings on switching.

Again in theory: If you are 100% cooling with a 4 COP AC unit, then you'll end up with another 25% on top of the power spent on the freezer spent pulling that heat out of your house.

 

[45North]

Care to explain more? Why is it the "right" thing?

New ones are more energy efficient. Save the planet! Replace it.

 

[Hedges]

New ones are more energy efficient. Save the planet! Replace it.

Don't waste a single photon!

 

[SunDave]

New ones are more energy efficient. Save the planet! Replace it.

So use more stuff, and create more garbage to be efficient. Taking notes... Got it.

 

[Citlalatonac]

So use more stuff, and create more garbage to be efficient. Taking notes... Got it.

Think about all the jobs he's creating by getting a new freezer: someone's gotta make it, box it, ship it, unbox it, drive it, stock it, sell it! Getting a new freezer is his patriotic duty to capitalism!

 

[SunDave]

Think about all the jobs he's creating by getting a new freezer: someone's gotta make it, box it, ship it, unbox it, drive it, stock it, sell it! Getting a new freezer is his patriotic duty to capitalism!

Yes, makes sense. It is the same reason that I always break any windows I come across. Then, the window repair shops always have work.

 

[Dave911]

The freezer is inside the house.
I use quite a bit of electricity, so this freezer represents about 10% of my usage.
Its a big house and I have a large shop.

I live 20+ minutes from a decent grocery store. So I make a trip about every two weeks and load up. So the freezer is pretty important. Driving to the store more to avoid having a freezer doesn't make sense. Driving is not cheap. And it burns time.

I think Ill stick with the old reliable freezer for now. The door gaskets are tight. I might be able to add a little insulation inside it.

I need to fix a few things on my shop roof and then start installing panels. Running conduit, wire, etc. I still need to finish installing my inverter and hook up the batteries. Lots to do!

But thanks for all of the comments! They were thought provoking.