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  • GAS BTUH, CUBIC FEET & ENERGY - CONTENTS: How to Calculate, Measure, & Set LP "Bottled" Gas or Natural Gas Pressures & BTUH per Cubic Foot. What are the typical pressures in an LP or natural gas fuel system & how do they differ. What's the difference between butane & propane or natural gas? Can we just substitute butane for propane or LPG? [No.]
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Questions & answers about propane & natural gas BTUs & gas pressures & gas volumes:

This article answers common questions about how to calculate various measures of natural gas and propane, including conversion between cubic feet and gallons and BTUs.

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LP "Bottled" Gas or Natural Gas Pressures & BTUH per Cubic Foot

American Gas Meter AC 95 refurbished at eBay (C) InspectApedia.comGeneral safety warning: improper installation and even improper inspection and testing methods involving natural or "LP" gas can involve dangerous conditions and risk fire or explosion.

If you smell gas you should leave the building immediately and should do so without doing anything that could create a spark such as operating a light switch or telephone. From a safe location, call your gas company's emergency line and/or your fire department. The text provided here is a working draft and may be incomplete or inaccurate.

Recently-posted questions & answers about fuel gas BTUs, volumes, weights, and other properties posted originally at GAS BTUH, CUBIC FEET & ENERGY

On 2017-04-17 by (mod) re: how to convert cubic feet gas meter readings to gallons of propane


I didn't find a detailed specification for the American AC-95 LP gas meter, but from a look at its data tag right on the propane meter we see that it is a temperature-compensated meter that reads gas usage in cubic feet at 60 degF. As you'll see in the article above, temperature and pressure have to be considered when reading gas volumes.

From the article text:

One gallon of LP-gas (propane or C3H8) weighs about 4.20 lbs (at 60 degF), contains about 8.66 cubic feet of gas vapor per pound (at 60 deg. F), ...
So we can calculate that at 60F, 1 gallon of LP gas = (4.20 lbs x 8.66 cuft/lb) = 36 cu.ft. of gas vapor per gallon
we can divide your cubic feet of gas usage by the gas volume per gallon

48 / 36 = 1.33 gallons - so you've used about 1.3 gallons of liquid propane.

The sticker reading Temp. Comp. Cu.Ft. @ 60degF means that the meter is designed to compensate for variations in actual temperature when measuring the cubic feet of gas passing through it, but its dials should always be interpreted as the volume of gas that would have passed through at 60F - if the meter didn't do this it would be impossible to make sense of its readings since temperatures vary around the meter constantly.

On 2017-04-17 8 by Teri

How do I calculate how much propane has been used from my American Meter Division AC-95 propane meter? the starting reading was 8575 and the ending reading was 8623 = 48. Do I then multiply the 48 X 7.48052 to get the gallons used?

My meter has a red sticker on it that says "Temp. Comp. Cu. Ft. @ 60". I'd love any help!

On 2017-03-21 18:21:56.514495 by (mod) re: DIY gas appliance orifice conversions

Ken please see CONVERT the GAS ORIFICES - at found by using the search box above to search for "convert lp to natural gas"

But I think a generic answer is not quite safe anyway; specifying an orifice without specifying pressure and fuel that's being converted (TO or FROM) is dangerous. Best bet, let's state the question so an engineer can't duck it, then look on your smoker to identify the brand and model, then ask the manfuacutrer to send you the right orifice parts.

Somethiing like:

Can you provide me with the proper orifices in a conversion kit to convert my BrandX ModelY smoker (made by you) from LP gas to Natural gas?

Or from Natural gas to LP gas? if that's your situation.

On 2017-03-21 by Ken

I have a #48 Orifice in a five burner smoker it's a 30×24×70 and am trying to find the right size orifices to convert ot

On 2017-03-03 by (mod) re: Can a 200.000 btu gas control valve be used on a 75.000 btu furnace?

I think so, Terry. Let me know if further questions arise.

On 2017-03-03 by Terry

Hi, Thanks for the response, My valve does say 200.000 max. pressure. I assume this valve will work on anything up to 200.000 My question is answered Thanks, Terry

On 2017-03-02 by (mod)

I don't know, Terry. Look closely at the gas control valve labeling or find its specification sheet. The 200kBTUH number may be a maximum that the valve accomodates; the spec sheet will give an operating range of btus.

On 2017-03-01 by Terry

Hi, Can a 200.000 btu gas control valve be used on a 75.000 btu furnace?

On 2016-11-08 by (mod) re: if we use 150 cubic meters (liters) of gas vapor per day at 50c per liter How much is this per cubic meter M3 of Vapor.

Thanks for the excellent question. You'll see in a moment that temperature is a source of variation in estimates of converting a volume in liters of LPG (liquid) to a volume in cubic meters of propane (gas)

In general you can convert

LPG liquid volume in litres to m³ of propane gas as 1L LPG = 0.27m³ gas This is the key formula you need.

Multiply # Liters of LPG x 0.26 to get gas volume in cubic meters

If 1 Liter costs 0.50 (50 cents per liter), then that's the cost for 0.26 cubic meters of gas.



1 cubic meter m³ of propane gas converts to 3.07 litres of LPG liquid (1m³ = 3.70L)

How to convert from liters of liquid propane (LPG) to volume of propane gas in cubic meters:

1 Liter of LPG = 0.27m³ of propane gas

Remember that 1 cubic meter (m³) = 1000 Liters of anything

How to convert from cubic meters of propane gas to liquid volume in liters of LPG:

1 cubic meter of LPG (gas) = 3.93 liters of propane gas vapor at 8 deg C. Other sources give the conversion number as 3.67 or in the E.U. officially 3.85.

Why the confusion of multiple conversion numbers? Because the ambient temperature affects the volume of gas vapor that you'll get from a liter of liquid LPG.

Some sources prefer to work in units of energy (gigajoules) to get around the temperature problem, but to avoid drowning you in numbers we'll keep that aside for now.

Citations: this Australian source (ELGAS) is particularly clear and helpful

On 2016-11-08 by Chris

Hi, hope you can help. I have a main LPG tank with my fuel being delivered in Liters & the tank has a very old fashion gauge.

So we fitted another secondary gas meter that reads in Cubic meters of vapor but cant work out how to convert.
IE: if we use 150 cubic met of vapor per day at 50c per liter How much is this per CM of Vapor.
Hope you can help,
Many thanks,

On 2016-10-11 by Will

How many BTU are available, total, if the building has 2 lbs natural gas pressure coming in off tge street?

On 2016-10-05 by Willie

I live in a very rural area in Kentucky (moderate winters). And I'm looking to install a 25k BTU vent-free fireplace to supplement my electric heat pump when it gets extremely cold or for power failures. Any recommendations on how much LP Gas I should realistically expect to purchase to last all winter?

On 2016-07-04 by Kadi

Any advice on Average Daily Operating Hours to be considered for LPG fired Boilers in 5star Hotel.
I know LPG hourly consumption of the Boiler and I want to size the LPG storage tank.
Example: Average Daily Operating Hours x LPG Consumption for one Hour X storage days (say 10 days) = Tank Capacity

On 2016-06-23 y (mod) re: impact on appliance BTUh of converting between natural gas & Propane

You should be able to obtain the same BTUh output - the conversion will change pressure, regulator, and jets (different orifices)

200,000 BTU/hr furnace will use about 194 cubic feet of natural gas (100,000 ÷ 1,030 = 97.1 x 2) in one hour

200,000 BTU/hr furnace will use about 80 cubic feet of propane (100,000 ÷ 2516 = 39.7 x 2) in one hour

On 2016-06-23 by Dan

If I have a 200,000 btu heater that is running on natural gas and I want to convert
it to run on propane, what would be it's btu output running on propane?

On 2016-03-17 by (mod) re: Using well head gas in appliances


If I understand the question, "non-standard" natural gas is being used by some of your customers; the gas-burning appliance MUST be properly matched to the fuel properties; otherwise the risk is more than poor performance, there could be corrosion or fatal CO hazards.

You cannot simply change a gas pressure, as metering devices, orifices, controls may not work properly nor safely. I would call the manufacturer of a specific heater you're planning to install to ask what product part changes or adjustments are needed.

On 2016-03-17 by Anonymous

I am from west virginia and i am an hvac tech. there is a lot of well head gas(natural) that people use. 2100 btu content and gravity of 1.6. How do i work with this on New furnace installs?

On 2016-01-20 by (mod) re: How much propane will a propane 50 gallon hot water use


You can use the calculations in the article GAS BTUH, CUBIC FEET & ENERGY to answer your question: you need to look at the INPUT BTUH number on your water heater's data tag to make a precise calculation.

The article above tells us that

A typical residential water heater used to produce domestic hot water consumes about 45,000 BTUH for a 30 to 40 gallon water heater.

1 cubic foot of propane gas provides 2750 BTUs

One gallon of liquid propane contains about 91,500 BTUs and weighs about 4.20 pounds. One pound of propane contains about 21,500 BTUs.

On 2016-01-20 by Jennifer

How much propane will a propane 50 gallon hot water use

On 2015-11-10 by (mod) re: how to convert cubic meters of gas per hour to liquid gallons of propane used

David I suspect your meter, if it's metric, is giving cubic meters per hour since a square meter would be a bit flat.

To convert cubic meters to gallons by volume you use the formula:

Cubic Meters x 264.172 = gallons

or put another way,

1 cubic meter = 264.172 gallons.

On 2015-11-10 by David

My propane meter reads square meters/hour. How do I calculate the number of gallons used.


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