On Tue, 6 Jan 2026 12:52:27 -0500 (EST), kludge@panix.com (Scott
Dorsey) wrote:

Scott Lurndal <slp53@pacbell.net> wrote:

It's not uncommon to use NEMA L6-xxP/R connectors for 240VAC

appliances. For

120VAC non-GFCI circuits in a garage, one typically is required by NEC

to

use L5-20P/R receptacles and plugs to prevent Joe Sixpack from >>electrocuting himself in a wet garage.

Yes, I do think the twistlocks are a win for a number of reasons. And

they

do disconnect while plugged in, so you don't get the arc in your face if
you disconnect under load like you do with straight-blades. I have

never seen

them in a residential install but I'd love to see more of them.

Twistlocks or arcs?

Inquiring mind want to know!
--
"Here lies the Tuscan poet Aretino,
Who evil spoke of everyone but God,
Giving as his excuse, 'I never knew him.'"

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/4/26 08:36, Paul S Person wrote:

On Sat, 3 Jan 2026 13:54:15 -0500, Cryptoengineer
<petertrei@gmail.com> wrote:

On 1/1/2026 4:22 AM, Thomas Koenig wrote:

BCFD 36 <bcfd36@cruzio.com> schrieb:

<snippo>

What is 220 V used for in the US (assuming that this took place
there)? I assume it would be 220 V/60 Hz?

Stoves and clothes driers are the most common uses in domestic settings.
My EV charger is also on a 220 line.

Oil furnaces, while getting rarer as they are replaced by heat pumps,
use them.

Or at least ours does. As did the one before it.

Our central heating/cooling system motor for the house and the dryer are
on the 240 volt circuit. The actual heating, the stove, and the water
heater are all propane, as is the 22kw standby generator.

"Why a generator?", you may ask. Well, over Christmas our PG&E power was
out for 5 days. Expensive? Very! But no food spoiled, the TV and
confuser still worked, etc.

--
----------------

Dave Scruggs
Senior Software Engineer - Lockheed Martin, et. al (mostly Retired)
Captain - Boulder Creek Fire (Retired)
Board of Directors - Boulder Creek Fire Protection District (What was I thinking?)

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

BCFD 36 <bcfd36@cruzio.com> writes:

On 1/4/26 08:36, Paul S Person wrote:

On Sat, 3 Jan 2026 13:54:15 -0500, Cryptoengineer
<petertrei@gmail.com> wrote:

On 1/1/2026 4:22 AM, Thomas Koenig wrote:

BCFD 36 <bcfd36@cruzio.com> schrieb:

<snippo>

What is 220 V used for in the US (assuming that this took place
there)? I assume it would be 220 V/60 Hz?

Stoves and clothes driers are the most common uses in domestic settings. >>> My EV charger is also on a 220 line.

Oil furnaces, while getting rarer as they are replaced by heat pumps,
use them.

Or at least ours does. As did the one before it.

Our central heating/cooling system motor for the house and the dryer are
on the 240 volt circuit. The actual heating, the stove, and the water
heater are all propane, as is the 22kw standby generator.

"Why a generator?", you may ask. Well, over Christmas our PG&E power was
out for 5 days. Expensive? Very! But no food spoiled, the TV and
confuser still worked, etc.

Most of Carmel and Pebble Beach/17 Mile Drive and parts of Pacific
Grove and Monterey were also out for several days during that same set of storms.

Down here at the southern end of the Santa Cruz mountains, we didn't
have any power outages during the holidays - but I did have 12 total
outages in 2025, most due to overly sensitive safety device false-alarm disconnects during wildfire season, one due to a failed 50yo underground primary circuit and two due to auto-vs-power-pole [either related
to the dozen wineries in the area or the local high school kids].

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/7/26 11:29, Scott Lurndal wrote:

BCFD 36 <bcfd36@cruzio.com> writes:

On 1/4/26 08:36, Paul S Person wrote:

On Sat, 3 Jan 2026 13:54:15 -0500, Cryptoengineer
<petertrei@gmail.com> wrote:

On 1/1/2026 4:22 AM, Thomas Koenig wrote:

BCFD 36 <bcfd36@cruzio.com> schrieb:

<snippo>

What is 220 V used for in the US (assuming that this took place
there)? I assume it would be 220 V/60 Hz?

Stoves and clothes driers are the most common uses in domestic settings. >>>> My EV charger is also on a 220 line.

Oil furnaces, while getting rarer as they are replaced by heat pumps,
use them.

Or at least ours does. As did the one before it.

Our central heating/cooling system motor for the house and the dryer are
on the 240 volt circuit. The actual heating, the stove, and the water
heater are all propane, as is the 22kw standby generator.

"Why a generator?", you may ask. Well, over Christmas our PG&E power was
out for 5 days. Expensive? Very! But no food spoiled, the TV and
confuser still worked, etc.

Most of Carmel and Pebble Beach/17 Mile Drive and parts of Pacific
Grove and Monterey were also out for several days during that same set of storms.

Down here at the southern end of the Santa Cruz mountains, we didn't
have any power outages during the holidays - but I did have 12 total
outages in 2025, most due to overly sensitive safety device false-alarm disconnects during wildfire season, one due to a failed 50yo underground primary circuit and two due to auto-vs-power-pole [either related
to the dozen wineries in the area or the local high school kids].

And in San Francisco a large part of the Western part of the City was
without power with devastating consequences for the businesses there
that had refrigerators full of food as well as to private parties who
had to dispose of the stored food in their private refrigerators and
who depended on power to cook. This is not to mention the damage
by flooding to to communities in the Northern Bay Area where the
land can be quite low lying. The Embarcadero was flooded in
San Francisco which is becoming quite common in the winter storms.

I think the solution is not necessarily more CO2 emitting generators though they probably make up a relatively insignificant amout of pollution but
more widespread availablity of adequate battery storages change by either
line power when it is up and/or solar panels but that is up to the City.

bliss


--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/7/2026 12:39 PM, BCFD 36 wrote:

On 1/4/26 08:36, Paul S Person wrote:

On Sat, 3 Jan 2026 13:54:15 -0500, Cryptoengineer
<petertrei@gmail.com> wrote:

On 1/1/2026 4:22 AM, Thomas Koenig wrote:

BCFD 36 <bcfd36@cruzio.com> schrieb:

<snippo>

What is 220 V used for in the US (assuming that this took place
there)?ÿ I assume it would be 220 V/60 Hz?

Stoves and clothes driers are the most common uses in domestic settings. >>> My EV charger is also on a 220 line.

Oil furnaces, while getting rarer as they are replaced by heat pumps,
use them.

Or at least ours does. As did the one before it.

Our central heating/cooling system motor for the house and the dryer are
on the 240 volt circuit. The actual heating, the stove, and the water
heater are all propane, as is the 22kw standby generator.

"Why a generator?", you may ask. Well, over Christmas our PG&E power was
out for 5 days. Expensive? Very! But no food spoiled, the TV and
confuser still worked, etc.

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air conditioning easily, being a liquid cooled Mitsubishi turbo four
cylinder motor generator sold by Generac.
https://winsim.com/generator_back_finish.jpg

Since the generator starts and synchronizes in ten seconds, we get to
run it almost monthly due to the number of outages in our area.

Lynn


--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air conditioning easily,

7 tons of air conditioning?
--
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/10/2026 4:31 AM, Thomas Koenig wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air
conditioning easily,

7 tons of air conditioning?

Freedom units!

From Wikipedia:

"A ton of refrigeration (TR or TOR), also called a refrigeration ton
(RT), is a unit of power used in some countries (especially in North
America) to describe the heat-extraction rate of refrigeration and air conditioning equipment. It was originally defined as the rate of heat
transfer that results in the freezing or melting of 1 short ton (2,000
lb; 907 kg) of pure ice at 0 øC (32 øF) in 24 hours.[1][2]"

Is also 12,000 Btu/hour, or 3.5 kW.

pt



--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Cryptoengineer <petertrei@gmail.com> schrieb:

On 1/10/2026 4:31 AM, Thomas Koenig wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air
conditioning easily,

7 tons of air conditioning?

Freedom units!

From Wikipedia:

"A ton of refrigeration (TR or TOR), also called a refrigeration ton
(RT), is a unit of power used in some countries (especially in North America) to describe the heat-extraction rate of refrigeration and air conditioning equipment. It was originally defined as the rate of heat transfer that results in the freezing or melting of 1 short ton (2,000
lb; 907 kg) of pure ice at 0 øC (32 øF) in 24 hours.[1][2]"

Is also 12,000 Btu/hour, or 3.5 kW.

So 7 tons is around 24 kW (at 0øC, of course efficiency depends
on temperature; this is obviously a nameplate capacity. Actual
cooling capacity depends on the temperatures involved, obviously).

Sounds like a _really_ huge air conditioning unit, but I know that
building insulation is almost unheard of in the US.

On that topic: I recently browsed through a book on refrigeration
technology written in 1888 (which was a gift for one of my sons,
also an engineer). Although entropy was known in principle at the
time, it did not feature in the book, but adiabatic expansion and
compression did. The preface contained the statement that the
heat released from burning coal should be equal to the heat you
can remove in a refrigeration, as a theoretical limit. That is,
of course, bogus. The author also did not have the advantage of
consistent units; the first law of thermodynamics was formulated
really strangely.

One method for producing artificial ice struck me as really weird -
pull vacuum, part of the water will evaporate and the rest will
freeze. Yes, that will work, but is really inefficient.

But the drawings were great.

--
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/10/2026 3:31 AM, Thomas Koenig wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air
conditioning easily,

7 tons of air conditioning?

Two units, 3 tons (36,000 btu/hr, 10.5 kW, of a/c and 80,000 btu/hr, 23
kW, of heat) and 4 tons (48,000 btu/hr, 14 kW, of a/c and 100,000
btu/hr, 29 kW, of heat) for our 3,300 ft2 (307 m2) house with lots of insulation and triple pane windows.

The 4 ton a/c is oversized, it could be 3 tons easily, especially since
I converted it into two 60% zones with multiple thermostats.

Our outside extreme temperatures in the area range from 6 F (-14 C) to
113 F (45 C) over the last 40+ years. Our average temperatures range
from 25 F (-4 C) to 105 F (41 C).

My office building is 5,300 ft2 (492 m2) and has two four ton a/c units
with lots of insulation and double pane windows. The north side (cold
side) unit is a heat pump and south side (hot side) has electric strip
heat (10 kw). We do not need much heat due to the 12 computers that run constantly plus the extra disk drives, laser printers, communication equipment, etc.

Lynn


--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/10/2026 3:12 PM, Thomas Koenig wrote:

Sounds like a_really_ huge air conditioning unit, but I know that
building insulation is almost unheard of in the US.

And this is based on?

My last three houses, from 1996, have all been around R-20 in the walls
and R-30 in the ceilings.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/10/2026 6:01 PM, Jay Morris wrote:

On 1/10/2026 3:12 PM, Thomas Koenig wrote:

Sounds like a_really_ huge air conditioning unit, but I know that
building insulation is almost unheard of in the US.

And this is based on?

My last three houses, from 1996, have all been around R-20 in the walls
and R-30 in the ceilings.

When I bought my latest house in 2019, a house built in 1998 with single
pane windows, I replaced the single pane windows with triple pane
windows with a clear plastic insert in them for sound reduction. The
new windows dropped my electric bill by 40%.

Lynn


--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Thomas Koenig <tkoenig@netcologne.de> writes:

Cryptoengineer <petertrei@gmail.com> schrieb:

On 1/10/2026 4:31 AM, Thomas Koenig wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

"A ton of refrigeration (TR or TOR), also called a refrigeration ton
(RT), is a unit of power used in some countries (especially in North
America) to describe the heat-extraction rate of refrigeration and air
conditioning equipment. It was originally defined as the rate of heat
transfer that results in the freezing or melting of 1 short ton (2,000
lb; 907 kg) of pure ice at 0 øC (32 øF) in 24 hours.[1][2]"

Is also 12,000 Btu/hour, or 3.5 kW.

So 7 tons is around 24 kW (at 0øC, of course efficiency depends
on temperature; this is obviously a nameplate capacity. Actual
cooling capacity depends on the temperatures involved, obviously).

Sounds like a _really_ huge air conditioning unit, but I know that
building insulation is almost unheard of in the US.

Acutally, US building codes since the 1970s have required
substantial insulation. They've only become more strict
with time.

My house is insulated well enough that I don't need
air conditioning at all (coastal california).


--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/10/26 17:59, Scott Lurndal wrote:

Thomas Koenig <tkoenig@netcologne.de> writes:

Cryptoengineer <petertrei@gmail.com> schrieb:

On 1/10/2026 4:31 AM, Thomas Koenig wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

"A ton of refrigeration (TR or TOR), also called a refrigeration ton
(RT), is a unit of power used in some countries (especially in North
America) to describe the heat-extraction rate of refrigeration and air
conditioning equipment. It was originally defined as the rate of heat
transfer that results in the freezing or melting of 1 short ton (2,000
lb; 907 kg) of pure ice at 0 øC (32 øF) in 24 hours.[1][2]"

Is also 12,000 Btu/hour, or 3.5 kW.

So 7 tons is around 24 kW (at 0øC, of course efficiency depends
on temperature; this is obviously a nameplate capacity. Actual
cooling capacity depends on the temperatures involved, obviously).

Sounds like a _really_ huge air conditioning unit, but I know that
building insulation is almost unheard of in the US.

Acutally, US building codes since the 1970s have required
substantial insulation. They've only become more strict
with time.

My house is insulated well enough that I don't need
air conditioning at all (coastal california).

This apartment building in San Francisco was constructed before WW I
so has no insulation. Most of the time it is not missed. When I miss
it too
much I apply my local insulation or go back to bed.
There is a problem this year in that I cannot find my jacket liner.
A sweatshirt helps a lot but that liner was warmer and had pockets.

bliss



--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Thomas Koenig <tkoenig@netcologne.de> wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air
conditioning easily,

7 tons of air conditioning?

Weird American unit. Air conditioning system with the equivalent cooling capacity of seven tons of ice melting. We use BTUs too, God only knows why. Even the British don't use BTUs anymore. I think a ton is about 3.5kw.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/10/26 18:31, Scott Dorsey wrote:

Thomas Koenig <tkoenig@netcologne.de> wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air
conditioning easily,

7 tons of air conditioning?

Weird American unit. Air conditioning system with the equivalent cooling capacity of seven tons of ice melting. We use BTUs too, God only knows why. Even the British don't use BTUs anymore. I think a ton is about 3.5kw. --scott

I have never run across "tons" when talking about cooling. I don't think
it is common. I have seen BTUs, CFM at xxx degrees, etc. Google AI says
the following about European units:
"European air conditioning uses the International System of Units (SI), primarily Kilowatts (kW) for cooling/heating capacity, Watts (W) for
power, and Joules (J) or Kilowatt-hours (kWh) for energy, alongside
efficiency metrics like SEER, but you'll still see BTU/h on some labels
due to global standards, with the EU Energy Label specifying kW, kWh,
and SEER ratings."

--
----------------

Dave Scruggs
Senior Software Engineer - Lockheed Martin, et. al (mostly Retired)
Captain - Boulder Creek Fire (Retired)
Board of Directors - Boulder Creek Fire Protection District (What was I thinking?)

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 2026-01-11, Jay Morris <morrisj@epsilon3.me> wrote:

On 1/10/2026 3:12 PM, Thomas Koenig wrote:

Sounds like a_really_ huge air conditioning unit, but I know that
building insulation is almost unheard of in the US.

And this is based on?

My last three houses, from 1996, have all been around R-20 in the walls
and R-30 in the ceilings.

What is R-20 and R-30? Another kind of liberty unit? :-)

--
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 2026-01-11, Scott Dorsey <kludge@panix.com> wrote:

Thomas Koenig <tkoenig@netcologne.de> wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air
conditioning easily,

7 tons of air conditioning?

Weird American unit. Air conditioning system with the equivalent cooling capacity of seven tons of ice melting. We use BTUs too, God only knows why. Even the British don't use BTUs anymore. I think a ton is about 3.5kw.

A BTU isn't too bad - it is very close to one kJ.

But when discussing units with US colleagues, I usually cheat -
I have MathCad, which converts units just fine.

--
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/11/26 10:42, Thomas Koenig wrote:

On 2026-01-11, Jay Morris <morrisj@epsilon3.me> wrote:

On 1/10/2026 3:12 PM, Thomas Koenig wrote:

Sounds like a_really_ huge air conditioning unit, but I know that
building insulation is almost unheard of in the US.

And this is based on?

My last three houses, from 1996, have all been around R-20 in the walls
and R-30 in the ceilings.

What is R-20 and R-30? Another kind of liberty unit? :-)

You must not have shopped for insulation before.

There is a very good entry in Wikipedia about R rating: https://en.wikipedia.org/wiki/R-value_(insulation) that I won't
reproduce here. I recommend reading it. But it says that it is used in
both American and European settings.

This is the first paragraph of the article:
"The R-value is a measure of thermal resistance, specifically how well a two-dimensional barrier, such as a layer of insulation, a window or a
complete wall or ceiling, resists the conductive[2] flow of heat, in the context of construction.[3] The higher the R-value, the more insulating
the material is. Higher R-values can reduce heating bills in cold
weather and cooling bills in hot weather."

--
----------------

Dave Scruggs
Senior Software Engineer - Lockheed Martin, et. al (mostly Retired)
Captain - Boulder Creek Fire (Retired)
Board of Directors - Boulder Creek Fire Protection District (What was I thinking?)

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36 <bcfd36@cruzio.com> wrote: >I have never run across "tons" when talking about cooling. I don't think

it is common. I have seen BTUs, CFM at xxx degrees, etc.

It's pretty common for any industrial AC stuff. Americans also use
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Thomas Koenig <tkoenig@netcologne.de> wrote:

What is R-20 and R-30? Another kind of liberty unit? :-)

Yes, it's a measure of thermal resistance. Ironically, it appeared in the
US at a time when we were actively moving toward the metric system, back
in the seventies.

Nobody outside of construction folks actually use it. It was never mentioned in my thermo class. I saw how it was calculated and it was kind of a mess. --scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

BCFD 36 <bcfd36@cruzio.com> writes:

On 1/10/26 18:31, Scott Dorsey wrote:

Thomas Koenig <tkoenig@netcologne.de> wrote:

Lynn McGuire <lynnmcguire5@gmail.com> schrieb:

We ran on our 38 kW whole house generator last summer for four days
after hurricane Beryl in the Houston area. It runs our 7 tons of air
conditioning easily,

7 tons of air conditioning?

Weird American unit. Air conditioning system with the equivalent cooling
capacity of seven tons of ice melting. We use BTUs too, God only knows why. >> Even the British don't use BTUs anymore. I think a ton is about 3.5kw.
--scott

I have never run across "tons" when talking about cooling.

Often used in commercial HVAC circles. We had to put an 80
ton unit on the roof for our first datacenter back in 2005
in Santa Clara.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

BCFD 36 <bcfd36@cruzio.com> schrieb:

On 1/11/26 10:42, Thomas Koenig wrote:

On 2026-01-11, Jay Morris <morrisj@epsilon3.me> wrote:

On 1/10/2026 3:12 PM, Thomas Koenig wrote:

Sounds like a_really_ huge air conditioning unit, but I know that
building insulation is almost unheard of in the US.

And this is based on?

My last three houses, from 1996, have all been around R-20 in the walls
and R-30 in the ceilings.

What is R-20 and R-30? Another kind of liberty unit? :-)

You must not have shopped for insulation before.

Actually, I have, but in Europe.

There is a very good entry in Wikipedia about R rating: https://en.wikipedia.org/wiki/R-value_(insulation) that I won't
reproduce here. I recommend reading it. But it says that it is used in
both American and European settings.

This is the first paragraph of the article:

"The R-value is a measure of thermal resistance, specifically how well a two-dimensional barrier, such as a layer of insulation,

So it needs a unit, and it seems there are inconsistent units.
Or is it the inverse of a Nusselt number? Very probably not.

--
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artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Scott Dorsey <kludge@panix.com> schrieb:

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36 <bcfd36@cruzio.com> wrote:

I have never run across "tons" when talking about cooling. I don't think >>it is common. I have seen BTUs, CFM at xxx degrees, etc.

It's pretty common for any industrial AC stuff. Americans also use
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.

A good thing these were thrown out (except in the context of
nutrition, where they still occur).

Having different units for heat and mechanical energy is just
fundamentally broken, as is having things like Earth's gravity or
the density of certain liquids such as water or mercury in units
(except for their historical definition). Units just need to
be consistent.

I remember cracking up once when I read a definition of the
Reynolds number not as

Re = u * d * rho / eta

but as

Re = u * d * rho / (eta * c)

where c was the correction factor for the units, left unspecified,
of course. Hilarious!
--
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Sun, 11 Jan 2026 17:23:03 -0500 (EST), kludge@panix.com (Scott
Dorsey) wrote:

Thomas Koenig <tkoenig@netcologne.de> wrote:

What is R-20 and R-30? Another kind of liberty unit? :-)

Yes, it's a measure of thermal resistance. Ironically, it appeared in

the

US at a time when we were actively moving toward the metric system, back
in the seventies.

Nobody outside of construction folks actually use it. It was never

mentioned

in my thermo class. I saw how it was calculated and it was kind of a

mess.

Can I take it that actually measuring the effect with various
materials is not how its done?

(eg: closed room, various panels, heat/cold source on the outside,
thermometers on the walls/windows inside and out at the same height)

The /real/ question is: how is the thermal efficiency claimed for a
given oil furnace computed? Does someone just pull it out of his *ss
or is it something Marketing comes up with? Particularly measure
claiming to take into account the existing ducts.

Note that the thermal efficiency of a radiant electric heater is,
IIRC, 100%. I once explored this a little bit to try and figure out
the relative economics, but got lost in the details. Also note that
the current push against oil furnaces, at least up here, is based on
air pollution, not inefficiency or inadequacy.
--
"Here lies the Tuscan poet Aretino,
Who evil spoke of everyone but God,
Giving as his excuse, 'I never knew him.'"

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Mon, 12 Jan 2026 07:07:43 -0000 (UTC), Thomas Koenig
<tkoenig@netcologne.de> wrote:

Scott Dorsey <kludge@panix.com> schrieb:

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36

<bcfd36@cruzio.com> wrote:

I have never run across "tons" when talking about cooling. I don't

think

it is common. I have seen BTUs, CFM at xxx degrees, etc.

It's pretty common for any industrial AC stuff. Americans also use
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.

A good thing these were thrown out (except in the context of
nutrition, where they still occur).

Having different units for heat and mechanical energy is just
fundamentally broken, as is having things like Earth's gravity or
the density of certain liquids such as water or mercury in units
(except for their historical definition). Units just need to
be consistent.

But ... but ... but ... consistency is the hobgoblin of small minds.

I remember cracking up once when I read a definition of the
Reynolds number not as

Re = u * d * rho / eta

but as

Re = u * d * rho / (eta * c)

where c was the correction factor for the units, left unspecified,
of course. Hilarious!

I take it eta is some sort of constant whose manipulation can
counteract different units.
--
"Here lies the Tuscan poet Aretino,
Who evil spoke of everyone but God,
Giving as his excuse, 'I never knew him.'"

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Paul S Person <psperson@old.netcom.invalid> writes:

On Mon, 12 Jan 2026 07:07:43 -0000 (UTC), Thomas Koenig ><tkoenig@netcologne.de> wrote:

Scott Dorsey <kludge@panix.com> schrieb:

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36 =

<bcfd36@cruzio.com> wrote:

I have never run across "tons" when talking about cooling. I don't = >think=20
it is common. I have seen BTUs, CFM at xxx degrees, etc.=20

It's pretty common for any industrial AC stuff. Americans also use=20
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.

A good thing these were thrown out (except in the context of
nutrition, where they still occur).

Having different units for heat and mechanical energy is just
fundamentally broken, as is having things like Earth's gravity or
the density of certain liquids such as water or mercury in units
(except for their historical definition). Units just need to
be consistent.

But ... but ... but ... consistency is the hobgoblin of small minds.

Emmerson's original quote includes the word 'foolish', as in

'a foolish consistency is the hobgoblin of small minds'


--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Paul S Person <psperson@old.netcom.invalid> schrieb:

On Mon, 12 Jan 2026 07:07:43 -0000 (UTC), Thomas Koenig
<tkoenig@netcologne.de> wrote:

Scott Dorsey <kludge@panix.com> schrieb:

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36 <bcfd36@cruzio.com> wrote:

I have never run across "tons" when talking about cooling. I don't think >>>>it is common. I have seen BTUs, CFM at xxx degrees, etc.

It's pretty common for any industrial AC stuff. Americans also use
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.

A good thing these were thrown out (except in the context of
nutrition, where they still occur).

Having different units for heat and mechanical energy is just
fundamentally broken, as is having things like Earth's gravity or
the density of certain liquids such as water or mercury in units
(except for their historical definition). Units just need to
be consistent.

But ... but ... but ... consistency is the hobgoblin of small minds.

Asomov quoted this with regards to spelling of chemicals, or
hyphenation of words in a book, I think.

When a unit conversion error means a wrong result, not really,
and if you never know

I remember cracking up once when I read a definition of the
Reynolds number not as

Re = u * d * rho / eta

but as

Re = u * d * rho / (eta * c)

where c was the correction factor for the units, left unspecified,
of course. Hilarious!

I take it eta is some sort of constant whose manipulation can
counteract different units.

u is the velocity (m/s), d is a typical dimension (m), rho is the
density (kg/m^3) and eta the dynamic viscosity (Pa * s).

If you put in things in inconsistent units, you have put the
different units into that constant c.

--
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/12/2026 2:07 AM, Thomas Koenig wrote:

Scott Dorsey <kludge@panix.com> schrieb:

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36 <bcfd36@cruzio.com> wrote:

I have never run across "tons" when talking about cooling. I don't think >>> it is common. I have seen BTUs, CFM at xxx degrees, etc.

It's pretty common for any industrial AC stuff. Americans also use
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.

A good thing these were thrown out (except in the context of
nutrition, where they still occur).

Having different units for heat and mechanical energy is just
fundamentally broken, as is having things like Earth's gravity or
the density of certain liquids such as water or mercury in units
(except for their historical definition). Units just need to
be consistent.

I remember cracking up once when I read a definition of the
Reynolds number not as

Re = u * d * rho / eta

but as

Re = u * d * rho / (eta * c)

where c was the correction factor for the units, left unspecified,
of course. Hilarious!

A universal rib-tickler!

pt

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Paul S Person <psperson@old.netcom.invalid> schrieb:

On Sun, 11 Jan 2026 17:23:03 -0500 (EST), kludge@panix.com (Scott
Dorsey) wrote:

Thomas Koenig <tkoenig@netcologne.de> wrote:

What is R-20 and R-30? Another kind of liberty unit? :-)

Yes, it's a measure of thermal resistance. Ironically, it appeared in the >>US at a time when we were actively moving toward the metric system, back
in the seventies.

Nobody outside of construction folks actually use it. It was never mentioned >>in my thermo class. I saw how it was calculated and it was kind of a mess.

Can I take it that actually measuring the effect with various
materials is not how its done?

If I understand it correctly, the R - value is the inverse of
the U-value (which I am more familiar with).

If you have a temperatre difference across a wall (or something
similar) there will be a heat flux across it. The heat flux is
given as power per area, so it has the dimension of W/m^2 K.
q = Q/A, where q is the heat flux, Q the heat and A the area.

For a solid wall, the temperature difference ?T will be proportional
to the heat flux. This can be expressed in two ways:

q = U * ?T or q = ?T/R (if that it what it is), where U has
the unit of power per area and temperature, dimension W/(m^2 K)
(in liberty units probably BTU/(ft^2 deg F) or something like that.
High U values mean high heat conduction.

How do you calculate U? In a simple case, a homogenous wall made
of a simple isotropic a wall with thickness L will have
U = ? / L, where ? is the thermal conductivity of your material,
which is a property you can look up. Metals have high thermal
conductivity, isolation is specially designed for low thermal
conductivity. Air has very low thermal conductivity, but if left
to circulate, can transport a large amount of heat; therefore many
insulating materials (including clothing) basically keep air from
moving. (During an internship in the US, I actually once
looked up a thermal conductivity which was given as BTU per square
foot for a temperature gradient of one degree Fahrenheit per inch -
not even internally consistent. I returned the book and politely
asked for SI units).

If you look at walls made up of layers different materials, the
U value is the sum of the reciprocals of the individual walls.
It's not called U any more, but the formula then is

U = 1/(L_1/?_1 + L_2/?_2 + ... + L_n/?_n)

So, if you know the design of your wall and the individual values
of ? for your materials, you can calculate U. If you're using
R (which seems to be the inverse), the formula is easier, you
just add them up.

(eg: closed room, various panels, heat/cold source on the outside, thermometers on the walls/windows inside and out at the same height)

The /real/ question is: how is the thermal efficiency claimed for a
given oil furnace computed? Does someone just pull it out of his *ss
or is it something Marketing comes up with? Particularly measure
claiming to take into account the existing ducts.

You can determine that pretty well from measurements of flue
gas composition and temperature.

Note that the thermal efficiency of a radiant electric heater is,
IIRC, 100%. I once explored this a little bit to try and figure out
the relative economics, but got lost in the details. Also note that
the current push against oil furnaces, at least up here, is based on
air pollution, not inefficiency or inadequacy.

If the heating oil has low sulfur content and the nitrous oxide
values are controlled, that should not be a problem. Here, there
are mandatory annual measurements by a chimney sweep to control
CO and NOx.

--
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Paul S Person <psperson@old.netcom.invalid> wrote:

The /real/ question is: how is the thermal efficiency claimed for a
given oil furnace computed? Does someone just pull it out of his *ss
or is it something Marketing comes up with? Particularly measure
claiming to take into account the existing ducts.

There is a specific procedure from the DoE that you are supposed to use in order to create numbers that are legal to advertise. If you are measuring
for any other reason and not putting it into an ad, all bets are off.

Same thing as happens with consumer audio power ratings. If it is a
home audio product, it has to be measured with the FTC procedure. If
it's a car stereo product or a professional audio product you can just put
any random number on the datasheet.

Note that the thermal efficiency of a radiant electric heater is,
IIRC, 100%. I once explored this a little bit to try and figure out
the relative economics, but got lost in the details.

This is true, although some of the heat is created in transmission lines
and transformers rather than in your home. So if you do the math you
need to consider the losses as not contributing to your benefit even though
all the losses in the entire system eventually become heat somewhere.

Also note that
the current push against oil furnaces, at least up here, is based on
air pollution, not inefficiency or inadequacy.

Makes good sense. When I converted from oil to moderate-efficiency gas
there was a slight cost saving in fuel. But there was a huge saving in
my time scraping goo out of the oil filter and chipping debris out the
firebox every year, and a lot less need to clean my windows. Haven't had
to wake up cold in the middle of the night to go clean the filter since. --scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 11/01/2026 22:20, Scott Dorsey wrote:

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36 <bcfd36@cruzio.com> wrote:

I have never run across "tons" when talking about cooling. I don't think
it is common. I have seen BTUs, CFM at xxx degrees, etc.

It's pretty common for any industrial AC stuff. Americans also use
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.

Heh. Got my UK gas bill yesterday, it includes:

734.9 kWh - 23.5 gas units at 38.9 calorific value

In my case (it varies) a "gas unit" is 100 cubic feet (which isn't
stated on the bill); the calorific value is given in MJ/m^3 (which isn't stated on the bill); plus there is a "correction factor" of about 1.02
(which isn't even mentioned, never mind the exact value used being given
on the bill).

Still, they used to use therms. And maybe ergs, gallons and foot-pounds.
Or Batmans (a real unit, though now obsolete, and unrelated to Mr Wayne).

Aargh, I just found out they still use therms sometimes.

dunks head in bucket



Kiloseconds, anyone? 16 min 40 seconds.
Megasecond? 11 days 13 hours, 46 minutes and 40 seconds.
Gigasecond? about 31.7 years (about 'cos leap years etc)

millisecond - too fast for you or me, a young fit cat takes about 20 milliseconds to react
microseconds - timing accuracy of detonations in an atomic bomb
nanoseconds - light travels about a foot (see Grace Hopper)




Peter Fairbrother





--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 2026-01-13, Peter Fairbrother <peter@tsto.co.uk> wrote:

On 11/01/2026 22:20, Scott Dorsey wrote:

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36 <bcfd36@cruzio.com> wrote:

I have never run across "tons" when talking about cooling. I don't think >>> it is common. I have seen BTUs, CFM at xxx degrees, etc.

It's pretty common for any industrial AC stuff. Americans also use
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.

Heh. Got my UK gas bill yesterday, it includes:

734.9 kWh - 23.5 gas units at 38.9 calorific value

In my case (it varies) a "gas unit" is 100 cubic feet (which isn't
stated on the bill);

That seems to be off, there may be a factor of (10^3)^n somehwere
in there.

the calorific value is given in MJ/m^3 (which isn't
stated on the bill); plus there is a "correction factor" of about 1.02 (which isn't even mentioned, never mind the exact value used being given
on the bill).

A correction factor for you not paying enough money, obviously :-)

Still, they used to use therms. And maybe ergs, gallons and foot-pounds.
Or Batmans (a real unit, though now obsolete, and unrelated to Mr Wayne).

Aargh, I just found out they still use therms sometimes.

dunks head in bucket

Kiloseconds, anyone? 16 min 40 seconds.
Megasecond? 11 days 13 hours, 46 minutes and 40 seconds.
Gigasecond? about 31.7 years (about 'cos leap years etc)

I recently looked through a presentation by Rob Pike on 10**9
seconds of UNIX history.

millisecond - too fast for you or me, a young fit cat takes about 20 milliseconds to react
microseconds - timing accuracy of detonations in an atomic bomb
nanoseconds - light travels about a foot (see Grace Hopper)

You obviosly forgot microfortnight :-)

And, of course, the FFF unit system, of which the above is a
derived unit. It is at least consistent; velocities are then
measured in furlongs per fortnight.

--
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 1/12/2026 10:15 PM, Peter Fairbrother wrote:

On 11/01/2026 22:20, Scott Dorsey wrote:

In article <10k0qgo$3r1s$1@dont-email.me>, BCFD 36
<bcfd36@cruzio.com> wrote:

I have never run across "tons" when talking about cooling. I don't think >>> it is common. I have seen BTUs, CFM at xxx degrees, etc.

It's pretty common for any industrial AC stuff.ÿ Americans also use
"BTU" when we mean "BTU/hr" which is almost as bad as the whole
"calories meaning kcal" mess.

Heh. Got my UK gas bill yesterday, it includes:

734.9 kWh - 23.5 gas units at 38.9 calorific value

In my case (it varies) a "gas unit" is 100 cubic feet (which isn't
stated on the bill); the calorific value is given in MJ/m^3 (which isn't stated on the bill); plus there is a "correction factor" of about 1.02 (which isn't even mentioned, never mind the exact value used being given
on the bill).

Still, they used to use therms. And maybe ergs, gallons and foot-pounds.
Or Batmans (a real unit, though now obsolete, and unrelated to Mr Wayne).

Aargh, I just found out they still use therms sometimes.

dunks head in bucket

Kiloseconds, anyone? 16 min 40 seconds.
Megasecond? 11 days 13 hours, 46 minutes and 40 seconds.
Gigasecond? about 31.7 years (about 'cos leap years etc)

millisecond - too fast for you or me, a young fit cat takes about 20 milliseconds to react
microseconds - timing accuracy of detonations in an atomic bomb
nanoseconds - light travels about a foot (see Grace Hopper)

These days, physicists are studying events at the attosecond scale,
about the time it takes light to cross an atom.

https://phys.org/news/2024-10-fast-quantum-entanglement-scientists-attosecond.html

pt

--- PyGate Linux v1.5.2
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)