[Pretorian]

$this->bbcode_second_pass_quote('I_Like_Plants', 'T')he washers here take HOURS to wash the clothes, who knows how much water used, and they're top loaders too. Also, using dryers is mandatory, no clothes lines allowed.

[kanman]

Well air has a specific heat capacity of approx 1.01 and a density that varies with temp and pressure but is obviously pretty low. Let's use 1.3 Kg / M3 which is 36.8g per cu ft. So for each cu ft of cold air that spills out you need 1.3 watts * 36.8 *20 (assumed temp difference in C or K) = 957 watts. So we can round this to 1 Kw for a second for each cu ft of empty air space.

This ignores temperature losses from the fridge contents which may be more significant but either way your man at Sunfrost is spot on.

If you want efficiency, better insulation and reducing the amount of produce cooled (e.g. don't leave the milk out of the fridge to get warm) are the things to concentrate on.

[Gideon]

$this->bbcode_second_pass_quote('coyote', '')$this->bbcode_second_pass_quote('I_Like_Plants', 'A')lso, using dryers is mandatory, no clothes lines allowed.

[WatchfulEye]

I don't really know what the energy consumption of top loaders is, but I do know they use a lot more water. Top loaders are basically unheard of in Europe.

I did once have a top loader, that a landlord provided in a rented apartement. However, it wasn't an American style top-loader, it was basically a European front loader, but with the door on the top, and a second door in the drum.

A typical European front loader uses about 10 (US) gallons of water and 0.6 kWh of electricity for a normal (8 lb) wash. A full load in a big machine (15 lb) is about 15 gallons and 1 kWh. (Those figures are for sanitary wash temperatures - if you were to wash cold, it would be about 0.25 kWh - 0.3 kWh). Typical detergent usage is about 2 oz per full load.

That level of water and energy use is such that it's probably more energy and water efficient to use the machine to do the washing, rather than try doing it by hand.

[coyote]

$this->bbcode_second_pass_quote('Gideon', 'I')ncredibly wasteful and elitist, in my opinion, but rational.

[Pops]

And reduce the relative volume of air to thermal mass which only needs one chilling …

Jugs of water to displace the air maybe?

[kanman]

Well I agree that reducing the amount of free airspace is a good thing, especially if that is all you can do. If you use a high thermal mass (like water) to do it, you have the advantage that your fridge stays cold for longer in the event of power loss but this thermal mass takes energy to cool it. If it's going to stay there for years then fine (but why have such a big fridge).

If you have a variable demand for fridge space and are likely to be removing your 'filler' to replace with food, assuming you don't have frequent blackouts I would argue that a low thermal mass solution i.e. empty airtight containers would be more effiecient.

[coyote]

$this->bbcode_second_pass_quote('Gideon', 'U')nfortunately, people are animals, and are born with a set of premises that are usually never overcome.
Looking good at the expense of being good is one of them.

[gg3]

Frank, keep the F&P, those are good machines. Just recycle the graywater in some way.

For example, get a 50-gallon steel drum (new if possible so it's not got some kind of God-knows-what residue in it). Have a garden hose connection welded on to the side within a couple inches of the bottom. Squirt some kind of waterproofing compound (basin/tub/tile sealant is useful for this but you have to let it dry thoroughly) around the inside seams to prevent leakage.

Now attach a garden hose, the other end of which goes to a lawn sprinkler downhill from the drum. As the drum fills, it waters the yard.

NOTE, important: don't let kids or pets go into that part of the yard at least until it's had a full day of sunlight after each watering. Reason why: graywater from the wash cycle has germs in it including poo germs from underwear (even if you think your bottom is clean, it's not quite sanitary, there are still poo germs around and they get in your underwear).

Graywater from the rinse cycle is usually clean enough to not worry about unless someone has a contagious illness, after all, you're about to wear the clothes that just came out of that rinse water.

You can also use that graywater to flush the toilets, if you're up to building a contraption to store it and pump it into a tank that can gravity feed into the toilet tanks. The most important consideration here is to disconnect the clean water input from the toilet tank altogether, to avoid the risk of graywater being siphoned back into the clean water line in the event of a low water pressure condition (if that happens, it can lead to bacterial growth in your pipes, not good). So, disconnect the clean water line from the toilet, and connect up the graywater line from your graywater tank to the input to the toilet.

I've designed a bunch of these things, it's not hard. You can even make the process run itself automatically, using 12-volt bilge pumps and some switches & relays and so on.

---

Front loaders vs. top loaders.

Front loaders use less water, top loaders use less electricity, choose according to what is more scarce in your area. If you have a nuclear plant, wind farm, or other climate-clean relatively peak-proof energy source, go for the front loader. If your electricity comes from fossil fuels or from off-grid sources, go for the top loader.

Front loaders are inherently more complicated since they have to handle off-balance spin without shaking themselves to pieces. The load in a top-loader is inherently more likely to be distributed evenly when the spin cycle starts, than in a front-loader where it's all at the bottom of the drum and the machine has to start up slowly to attempt to distribute it evenly before getting up to high speed. Front loaders also have to have a watertight seal at the door, and a few other things I can't recall at this very moment. So in the long run, a top loader will tend to last longer because it's more mechanically simple.

Rinsing is what uses the most water: in effect it is trying to achieve the diffusion of the residual detergent from the clothes back into the water, and there is a limit to the amount of detergent residue the water will accept (basically down to an isotropic concentration vs. what's in the clothes). Thus the need for repeat rinse cycles.

The way to deal with the rinse problem is to use less detergent. Detergent makers tend to want you to more than necessary, not just so they can sell more detergent, but so they can be sure that every load comes out sparkling clean and you'll be satisfied with how the detergent is working. However this ends up requiring more rinses to get the residue out of the clothes (if you can smell it, it's still in there).

So, start by using half the recommended amount of detergent (in some cases you may be able to get down to 1/4 the recommended amount, experiment carefully and take notes). If your washer has a soak setting where it just lets the clothes sit in the water before turning on the agitator (or in a front-loader, revolves slowly for 5-10 minutes before going into full-on wash mode), this will help. The soaking will loosen up dirt so that less detergent is needed to remove it. Also warm water will do likewise, and by "warm" I mean lukewarm is sufficient in most cases, so the added energy cost for that water is minimal compared to hot. (Save the hot water for use when someone has a contagious illness.)

When reducing detergent, check the water being discharged from rinse (let it splash into a separate container, for example a hold a pot under the discharge hose). If there's a lot of suds, you need yet another rinse. If there are no suds, you don't need another rinse. If there's a small amount of suds but not much, you can probably get away without running another rinse.

In any case, with automatic washers, take notes on what actually happens in each cycle. This will give you a measure of flexibility for things like "one rinse only" or "need another rinse."

---

[WatchfulEye]

Top loaders do use less electricity than front loaders, and are quicker - but the catch is that this only holds for cold water washes.

However, the wash action is less effective and requires the use of large quantities of water and large quantities of detergent.

In Europe, it's customary to wash in warm water (except for the most delicate of materials, e.g. wool or silk), or hot water (sanitary washing for bedding, etc.) Once the energy for water heating is taken into consideration, there's really no contest. A top loader uses about 4x as much water and would require about 4x as much water to be heated - as it is heating that is the big energy consumer (not mechanical action), the front loader wins out.

The front loader has a further advantage in that their mechanism allows much faster spin speeds - 1500 rpm spin speed isn't that uncommon, and high energy efficiency machines may do 1800 rpm, or even higher. Indeed, the best machines have spin performance as good as a dedicated spin dryer. Which adds up to further energy savings if powered drying is used.

Again, the lower water volume used means less detergent, etc. I once bought some laundry detergent from a branch of 'Costco' in the UK, not realising that it was formulated for top loaders. I followed the instructions (basing the amount of detergent on the weight of laundry), and an hour later, there were suds overflowing from the washing machine all over the floor.

[lys3rg0]

$this->bbcode_second_pass_quote('', ' ')A top loader uses about 4x as much water and would require about 4x as much water to be heated

[trotsky]

The refrigerator is the biggest energy consumer in the house by far. It is using energy 24 hours a day, 7 days a week. The more hours you can save on its off cycles, the better. Nothing else in the house uses as much energy. Even an electric stove is only used about an hour a day at 5-10 kw per use.

[BobWallace]

$this->bbcode_second_pass_quote('trotsky', 'T')he refrigerator is the biggest energy consumer in the house by far. It is using energy 24 hours a day, 7 days a week. The more hours you can save on its off cycles, the better. Nothing else in the house uses as much energy. Even an electric stove is only used about an hour a day at 5-10 kw per use.

[strider3700]

$this->bbcode_second_pass_quote('mistel', 'V')ery nice of Chris to respond to me. I believe him, I just think the whole design of fridges is wrong. I know that every time I open my fridge, my feet get cold and the compressor kicks on. It can't be efficient. I have a kill a watt on the way and I will take some real world measurements of my 2 year old fridge.
Peter

[BobWallace]

"Don't get me wrong, sunfrost makes beautiful appliances. They aren't inexpensive however. Some of their models do have an advantage of being ready to run directly from your battery banks which is nice. No way to do that cheap at home."

Not sure about that. You can get the type compressor commonly used in boat construction and build your own heavily insulated box. Twelve volts shouldn't be hard to find. Perhaps 24vdc.

I think Sun Frost uses fairly standard DC compressors.

One might even be able to convert an old chest freezer and have a nice, easily cleanable interior and good latching system.

[gg3]

I'm surprised I missed this topic so far, because I've been doing exactly this experiment and recording the results.

First, re. Trotsky: two significant errors:

1) The fridge isn't the biggest energy consumer in the house; heating & cooling come first, the fridge comes second.

2) Using the stove & oven, "5 - 10 KW per use." Do you mean 5 - 10 KWH? If your cooking appliances (stove, oven, microwave) are using that much per day, that's a hell of a lot more than the fridge, in which case the fridge comes in third in the list.

Energy consumption for cooking is highly variable depending on your cooking habits. One burner on a stove can use 1,500 watts, or 1.5 KW, and if you run it for a half hour that's 0.75 KWH. If you do that every day, that's 273.75 KWH/year. However, power to each burner is controlled by a knob that either varies the power level or varies a thermostat setting. Then there's the oven, which can be another 1,500 watts, and is typically in use for longer periods because baking takes longer than simply boiling water or whatnot.

Ranges are typically connected to 240 volt circuits so you can't plug them into Kill-A-Watt meters; it would be interesting to develop a meter that can measure the actual power consumption over time, of a range. It is possible that a digital "clamp-on ammeter" of the type electricians carry can do this; at least it can show power consumption from moment to moment and you can do your own arithmetic. What you'd do is sit there with a stopwatch and time the duration of each change in the reading on the meter, and do that for the duration of a typical cooking session.


Second, re. Energy Star:

Those ratings are based on a whole lot of embedded assumptions that are based on "typical family usage," and it is difficult to find out, for any given category of appliance, what the assumptions are.

For example, last time I saw a rating on my washer (Danby twin-tub, DTT-420W), it was something like 436 KWH/year. In fact a typical 6 lb. load uses 0.06 KWH (60 watt-hours), so if you do two loads a week, your actual power consumption is only 6.24 KWH/year, not 436 as the ratings claimed. (For a household of four people, you can quadruple that and end up with only 25 KWH/year.) So for this particular machine, the actual performance is from 18 to 70 times (that's "times" not "percent") more efficient than the number that's in ratings (!). And if the ratings are supposed to be factoring in the power consumption for heating water, that does no good for those of us who wash in cold water, or have solar hot water heating.

For fridges, the ratings make assumptions about ambient room temperature (see below), and about the amount of mass present inside the fridge (food being stored), and the number of times per day the door is being opened, and the duration of each opening of the door. These assumptions may have little to nothing to do with how you actually use the fridge.

And so now, finally, onward to fridges....

I've been running the chest fridge experiment for over a year, and having done so, put the units (one for refrigeration and one for freezing) into service at home. They replace a big old fridge, probably 1970s vintage, that came with the place (rental property), that was consuming an estimated 1,400 KWH/year (!) based on Kill-A-Watt readings.

The chest fridge / freezer units, together, consume an estimated 328 to 460 KWH/year based on Kill-A-Watt readings. Why the range...? Because power consumption for refrigeration is very very sensitive to ambient room temperature. This is true for any fridge/freezer. In the summer, the unit has to create a larger temperature gradient between inside and outside, and in the winter, a much lower gradient. If your summer indoor temps are 80 degrees and your winter indoor temps are around 65 (typical for me), you can see how the difference adds up. Right now at about 68 degrees, my units are using a total of about 0.9 KWH/day.

Things you need to know about modifying chest freezers:

One, the factory stock thermostat that comes with the unit is designed for temperatures in the range that freezers use, not fridges. So you will have to find a different thermostat that will give you the correct range.

Two, those little vents on the side, are where the compressor is located. You want to leave a foot of clearance next to those vents so the waste heat from the compressor (it gets very warm) can freely exit to the ambient air. You also want to leave at least 6" of clearance on the other sides and rear of the unit. This does make a difference, and it is significant. It will also make it easier for you to vacuum up the dust bunnies that accumulate around the fridge/freezer:-)

(Speaking of vacuuming, someone should do a power consumption test on those Roomba robots. I'd guess that using one of those very often and using the regular vacuum less often, will be more efficient than using the regular vacuum as often as you normally do.)

Three, putting a small computer cooling fan in the compressor compartment to vent the warm air will reduce power consumption of the compressor, thus making the fridge or freezer more efficient. However, the power consumption of the cooling fan has to be considered, and on balance, it seems to come out about even.

Four, you need a thermometer in the box so you can be sure of the temperature you've achieved.

The ideal temp for a fridge is 34 degrees Fahrenheit to keep food fresh as long as possible; and in no case should it be higher than 40 or your food will go bad in subtle ways that will make you very sick, as in food poisoning. (No, I didn't test this empirically to see when I'd get sick!:-)

A useful temp for a freezer is -1 degree Fahrenheit (that's "minus one," which is "thirty three degrees Fahrenheit below freezing;" not "one degree below freezing" which is "thirty-one degrees Fahrenheit"), and at this temperature, ice cream will be exactly the right consistency: properly frozen and frosty, but easy to scoop, not solid like concrete. Depending on your needs you may set the freezer to a lower temp (e.g. to freeze meat solid), but anything higher will result in premature food spoilage also.

Five, those Kill-A-Watt meters have a margin of error, and this will show your power consumption being higher than it actually is. When you plug in the meter, let the reading stabilize (takes about 20 seconds) and then press the Amps button (second from the left). You will typically see something like 0.01 to 0.05. That means 10 to 50 milliamps of constant power consumption that will add to the KWH readings and throw off your yearly extrapolation.

NOTE, each and every Kill-A-Watt meter is different. Some will consume 0.01 and some 0.03, and some 0.05, when nothing is plugged into them. You need to test the one you are using. Ideal case, let it run for 24 hours with no load, and look at the cumulative KWH reading for that time period, and make note of it so you can subtract it from any tests of items such as fridges that need to be left running for a while to accumulate totals.

In the case of my chest fridges, it was an extrapolated difference (with two Kill-A-Watt meters, one for each unit) of nearly 100 KWH/year, which made it look as if my units were consuming that much more power than they were actually consuming. So you have got to know how your Kill-A-Watt meter performs before you start taking readings.

Five, about other brands. Sunfrost is pretty well the gold standard, and yet they have also come in for some criticism on the blogs. If I recall correctly, the RF-14 unit (mid-sized fridge/freezer) was claimed to have a yearly power consumption of 164 KWH/year. There's also the EcoFridge which comes in around 250 - 300, and is made in Northern Europe, but be aware that this unit is about 7 feet tall. A decent commercial fridge, e.g. Danby or major US brands, will come in at around 400 KWH/year. The chest fridge/freezer combo will come in around (yearly average) 350, which is still quite decent especially for the price.

About the convenience factor: you get used to top-loading very quickly. In fact there's a benefit. When you get something out of one side, you can place it on top of the other side while closing the lid. For example, open the fridge, take out the milk, place it on top of the freezer (as if it's a countertop surface), close the fridge, pour yourself a glass of milk. Having the horizontal space atop the adjacent unit lets you get stuff out and put it back more efficiently.

Six, fridges and kitchens. Building contractors tell me that the entire design of the kitchen is based on the fridge. Not only the layout of the cabinets, but the entire floorplan. If you're replacing a conventional fridge with a chest fridge/freezer combo, chances are you'll have to put one component where your fridge used to be, and the other component elsewhere in the kitchen.

In any case don't put 'em down the basement; carrying food up & down stairs is a pain in the butt and stairway falls are the #1 cause of household injuries.

Last but not least: the chest freezer/fridge combo takes up more space lengthwise, but sticks out less into the room than a conventional fridge. In some floorplans, this will actually work better than a conventional fridge (I've been designing house floorplans recently also).

OK, gotta scoot, back later...

[BobWallace]

I'm late to this discussion and didn't pick up on how large (how much interior space) your r/f setup provides.

My 18 cu.ft. Kenmore uses around 0.9 kW on a cool summer day and around 1.2 on a hot summer day. (That's at multiple 24 hour days during various weather cycles..)

Using the high number I would use 422 kW per year.

That's about 23.4 kW per cu.ft. per year.

How does your system compare on a cu.ft. basis?

[SolarDave]

$this->bbcode_second_pass_quote('gg3', '(')Speaking of vacuuming, someone should do a power consumption test on those Roomba robots. I'd guess that using one of those very often and using the regular vacuum less often, will be more efficient than using the regular vacuum as often as you normally do.)

[nocar]

Location, location, location.

Lots of people do not think about where they place their fridge/freezer. Obviously the temperature where the coils that give off heat is situated is essential ('ambient temperature'). The cooler and more ventilated the better, since the fridge/freezer has to work less.

Make it work less

And of course you should avoid putting hot or warm things into it, and avoid opening the door.

When it is freezing temps outside, you can put plastic bottles with water outside til they freeze and then place in the fridge. And things that you are going to put into the freezer can be frozen outside first (beware of dogs and such, so they do not steal your food)

nocar

[patience]

I want to improve our fridge and freezer this year, and studied this thread with enthusiasm!

Just remembered an old thing from childhood, that a lot of old folks in the 1950's kept the freezer on an unheated porch. They almost never ran in winter... Anybody know the downside to this? I'm thinking that could be hard on a compressor, starting with colld oil, etc. Ideas anyone?