# Most efficient refrigerator

M

#### m Ransley

Jan 1, 1970
0
Sun Frost is advertised as the most efficient refrigerator . The RF19
model consuming 770 watt per day at 70 degree or 281 KWH yearly.
I purchased a Sears Kenmore model 61982 18.8 cu ft . Gov rating on
consumption is 417 KWH yearly.
Well i covered it with 1 " r 7.2 foamboard and recessed it. my
last 10 day KWH use was 560 watt per day or 204 KWH yearly, measured
with a Kill-A -Watt.
Now im at 69 degree , single , But cook all food. I Beleive the KWH
Gov rating is to replicate a family and yearly temperature swings,
so when its warm it will consume more in its ratings. The Sun Frost has
a much higher 90 degree consumption quote of 1.09 KWH daily or 398
KWH yearly, And is this reflective of a familys use ? I dont think
so......
So who makes the most Efficient refrigerator?? Yes, Sears is better
than most people think.
I feel its underated and less than 1/2 the cost.
And Sears delivers free, { sometimes }

N

#### Nick Pine

Jan 1, 1970
0
m Ransley said:
Sun Frost is advertised as the most efficient refrigerator . The RF19
model consuming 770 watt per day...

Nonono. Energy units are watt-HOURS per day.

Nick

M

#### m Ransley

Jan 1, 1970
0
I know you are thinking , well he insulated it. Yes , not the back yet
, and 2 more inches will go on for r 21.6
The point is anyone can do this, insulate it better and recess it .
making even better than my present KWH costs. And the initial cost of
the Sears is acceptable, as I feel the Sun Frost is not. Payback
period for a Sunfrost ? What payback !

M

#### m Ransley

Jan 1, 1970
0
Nick ,Who uses energy units Where are they displayed for anything. I
have never heard of that term

M

#### m Ransley

Jan 1, 1970
0
OK nick you are right, I printed it wrong, but I beleive my numbers
and theory are correct

H

#### Harry Chickpea

Jan 1, 1970
0
Sun Frost is advertised as the most efficient refrigerator . The RF19
model consuming 770 watt per day at 70 degree or 281 KWH yearly.
I purchased a Sears Kenmore model 61982 18.8 cu ft . Gov rating on
consumption is 417 KWH yearly.
Well i covered it with 1 " r 7.2 foamboard and recessed it. my
last 10 day KWH use was 560 watt per day or 204 KWH yearly, measured
with a Kill-A -Watt.
Now im at 69 degree , single , But cook all food. I Beleive the KWH
Gov rating is to replicate a family and yearly temperature swings,
so when its warm it will consume more in its ratings. The Sun Frost has
a much higher 90 degree consumption quote of 1.09 KWH daily or 398
KWH yearly, And is this reflective of a familys use ? I dont think
so......
So who makes the most Efficient refrigerator?? Yes, Sears is better
than most people think.
I feel its underated and less than 1/2 the cost.
And Sears delivers free, { sometimes }

Up until the early 1990s, sunfrost had a major edge. Around that time tere was
a competition for the most energy efficient model refrigerator with a large
cash prize, and the major manufacturers got on board the efficiency bandwagon.
We recently bought a 25 cu ft refrigerator from sears that uses about 1/2 (or
less) the energy of our old 19 cu ft model.

Using foamboard can be counterproductive on some refrigerators, the smaller
units especially place the condensing coils just under the surface of the
sideas and top and depend on airflow over them to carry away the excess heat.

B

#### Bob Peterson

Jan 1, 1970
0
IIRC, the cheap fridge I bought was listed as using something like $60 a year worth of electricity, so that would be like 600 kwh per year. The next step up in efficiency would have saved about$20 a year in electricity but
cost something like \$300 more. Not much of a bargain IMO, unless you are on
very expesnive electricity.

E

#### Ecnerwal

Jan 1, 1970
0
I'm fairly negatively impressed that even the "new, more efficient"
regiferators of recent years still have the most inefficent placement of
the compressor and coils (hot parts). This was done efficently in the
1930's - hot parts on top, cold down below, arranged for excellent
airflow through the hot coils.

Now you have a hot compressor underneath a cold fridge, and the coils
either behind or (worse yet) wrapped all around the outside under the
models are more inefficient becasue the freezer (coldest) is placed near
the compressor (hottest).

E

#### East-of-lake

Jan 1, 1970
0
Ecnerwal said:
I'm fairly negatively impressed that even the "new, more efficient"
regiferators of recent years still have the most inefficent placement of
the compressor and coils (hot parts). This was done efficently in the
1930's - hot parts on top, cold down below, arranged for excellent
airflow through the hot coils.

Now you have a hot compressor underneath a cold fridge, and the coils
either behind or (worse yet) wrapped all around the outside under the
models are more inefficient becasue the freezer (coldest) is placed near
the compressor (hottest).

So I should look for a used commercial frig that has the compressor on top?
Haven't looked at them before but (from my days in the restaurant biz) as I
remember it many of them do have the exaust grill on top and storage all the
way to the bottom so they must be mounting the "hot" parts on top.

W

#### William P.N. Smith

Jan 1, 1970
0
Ecnerwal said:
Now you have a hot compressor underneath a cold fridge, and the coils
either behind or (worse yet) wrapped all around the outside under the

This is one of the touted advantages of the SunFrost models, the
compressor is on top. Also, lots of insulation, a lower-powered
compressor (higher efficiency, but takes longer to cool down) and DC
options to eliminate inverter efficiency losses. Significantly higher
prices though...

E

#### Ecnerwal

Jan 1, 1970
0
So I should look for a used commercial frig that has the compressor on top?

Depends. If the unit is new enough to have a newer type, more efficienct
compressor, perhaps yes. An older one might lose enough efficiency in
the compessor end to fail to make up for good thermal design in
placement of parts. Hard to know for sure, since I suspect that
commercial units are probably exempt from the sort of energy labeling
that consumer units have had for the past several years. Then again,
they are generally built so that you could replace the compressor. All
the free-stanging commercial units I've met would want a lot more
insulation - only walk-ins seem to get heavy insulation.

I've often wondered if it might not be more efficient to put in a very
well insulated walk-in (with the compressor unit located outdoors). On
the one hand, it's large, but on the other hand, there's no problem
insulating the living heck out of it.

M

#### m Ransley

Jan 1, 1970
0
I agree they could get more efficiency with a top coil- compressor .
But the unit i have is rated the most efficient at Energy Star. I saw
a few top coil recessed models with low yearly KWH costs , Maybe Sub
Zero. But they were the nice expensive ones.

W

#### wmbjk

Jan 1, 1970
0
Ecnerwal said:
I'm fairly negatively impressed that even the "new, more efficient"
regiferators of recent years still have the most inefficent placement
of the compressor and coils (hot parts). This was done efficently in
the 1930's - hot parts on top, cold down below, arranged for excellent
airflow through the hot coils.

It would seem that room temperature air flooded over the hot parts would
be only somewhat warmer, and that extra heat could be easily compensated
for with a little extra insulation. Then the works can be on the bottom,
which is practical since that space would otherwise be closer to the
floor than is desirable for shelving. Sunfrost claims there's an
efficiency advantage to top mounting, it's probably little more than
marketing hype.

Wayne

N

#### [email protected]

Jan 1, 1970
0
Ecnerwal said:
I'm fairly negatively impressed that even the "new, more efficient"
regiferators of recent years still have the most inefficent placement of
the compressor and coils (hot parts). This was done efficently in the
1930's - hot parts on top, cold down below, arranged for excellent
airflow through the hot coils.

Air near the floor tends to be cooler, and hot coils with a chimney above
could have more natural airflow. Sunfrosts have "thermal accumulators,"
refrigerant heat stores to allow the hot side to cool even when the
compressor isn't running, an idea from the 30s that's disappeared from
most modern fridges.

Nick

Q

#### Q

Jan 1, 1970
0
Wouldn't a chest design be more efficient than a standard upright design? I
know it wouldn't sell because of current kitchen design.

Q

J

#### John Hall

Jan 1, 1970
0
Actually, modern uprights are damn efficient. When I finally had to replace
a 35+ year old upright last winter, the new one - about the same size - runs
only 700 watts, easy for generator use!

I think you missed the point that I think he was intending to make...
other things being equal, a chest design is more efficient because it
does not spill the cold air on the floor when opened. The falling cold
air is replaced by warm room air, which then has to be cooled when the
door is closed.

H

#### Harry Chickpea

Jan 1, 1970
0
John Hall said:
I think you missed the point that I think he was intending to make...
other things being equal, a chest design is more efficient because it
does not spill the cold air on the floor when opened. The falling cold
air is replaced by warm room air, which then has to be cooled when the
door is closed.

Hmmm, the mass of the air would be one factor and the humidity would be the
other. Of the two, I'm guessing the high humidity would be more important,
since the humidity has to be condensed into liquid, which could require
significantly more energy.

J

#### John Hall

Jan 1, 1970
0
Hmmm, the mass of the air would be one factor and the humidity would be the
other. Of the two, I'm guessing the high humidity would be more important,
since the humidity has to be condensed into liquid, which could require
significantly more energy.

Where I live "we don't have humidity", but I see your point.
It just makes the case stronger.

D

#### daestrom

Jan 1, 1970
0
John Hall said:
I think you missed the point that I think he was intending to make...
other things being equal, a chest design is more efficient because it
does not spill the cold air on the floor when opened. The falling cold
air is replaced by warm room air, which then has to be cooled when the
door is closed.

True. And a 'full' unit has less free air to 'spill'. Which is why a unit
that is full or nearly so runs more economically than an empty.

daestrom

N

#### [email protected]

Jan 1, 1970
0
daestrom said:
...And a 'full' unit has less free air to 'spill'. Which is why a unit
that is full or nearly so runs more economically than an empty.

OTOH, it has more surface to instantly condense water vapor
from room air with a 50 F dewpoint when the door is open.

Nick

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