Reading Gas Meter + Usage Reference

Why this matters

Gas meters tell you how much gas is flowing - useful for diagnosing equipment, identifying leaks, sizing replacements, + explaining customer's bill. The tech who can read + interpret a gas meter helps customers understand their consumption + spots problems early. This is the field card.

Gas meter basics

The gas meter measures the volume of gas flowing through it:

• Cubic feet (CF) OR hundred cubic feet (CCF) in US
• Cubic meters (m³) in metric countries
• Some meters: thousand cubic feet (MCF)

Volume × heat content of gas = energy delivered:

• Natural gas: ~1,000 BTU/CF (varies slightly by region)
• Propane (LPG): ~2,500 BTU/CF (delivered as liquid; vaporizes)

Common meter types

Diaphragm meter (residential standard):

• Mechanical; bellows alternate filling + emptying
• Most homes
• Counter display
• Test dial (small sweep hand)

Rotary meter (commercial / large residential):

• Rotors meshing inside chamber
• Higher capacity
• Different appearance

Turbine meter (industrial):

• Spinning impeller
• Very high capacity
• Not residential

Diaphragm with electronic readout:

• Modern AMR / AMI
• Transmits to utility
• Customer accesses data online

Meter location

• Outdoor on wall of house (most common)
• Inside basement (older homes, cold climates)
• Underground pit (uncommon)
• At property line (some newer subdivisions)

Always accessible per utility requirements; no obstruction.

Reading the meter

Counter display (cumulative usage):

• Read all digits left to right
• Last digit may be a partial sweep dial
• Units typically CCF (hundred cubic feet)

Test dial (small dial, 1/2 or 2 ft per revolution):

• Sweep hand
• Indicates instantaneous flow
• Stopped = no gas flowing
• Spinning = gas flowing somewhere

Identifying leaks

Like water meter, the gas meter can detect leaks:

1. Turn OFF all gas appliances in the home:

• Furnace OFF (switch at thermostat)
• Water heater pilot considered (may keep running)
• Range / oven all knobs OFF
• Gas dryer OFF
• Gas fireplace OFF + pilot OFF
• Any other gas equipment

1. Watch the test dial:

• Stopped = no leak
• Slowly moving = small leak
• Faster = larger leak

1. If still seeing flow with everything off: leak somewhere in piping OR appliance pilot.

A leak even small enough that the dial barely moves is significant - gas leaks are explosion / asphyxiation risk.

Quantifying gas use

Reading change:

• Take reading at start of period
• Take reading at end
• Subtract; multiply by units conversion

Per appliance estimate:

• Furnace 80,000 BTU/hr at full fire: 80 CF/hr
• Water heater 40,000 BTU/hr: 40 CF/hr
• Range top burner: 7,000-15,000 BTU/hr each: 7-15 CF/hr
• Gas dryer: 25,000 BTU/hr: 25 CF/hr

If clock test shows different than expected: equipment may be over- OR under-firing.

Clock test (HVAC)

To verify furnace firing rate:

1. Turn off all other gas appliances (water heater pilot OK; some keep small consumption)
2. Time the test dial through one full revolution (typically 2 cubic feet of gas)
3. Calculate: (2 CF × 3600 sec/hr) / time in seconds = CF/hour
4. Multiply by ~1000 BTU/CF = BTU/hour input

Compare to nameplate input. Match = good; significant deviation = combustion issue, gas pressure issue, OR appliance fault.

Equipment sizing implications

If replacing equipment:

• Customer's current gas meter capacity
• Service line capacity to home
• Some homes need larger meter for bigger equipment

Utility provides meter capacity rating; check if upsize needed before installing high-capacity new equipment.

Meter ratings

Residential meters rated by capacity:

• AC-250 (about 250 CFH max)
• AC-275 / AC-415 (older)
• 425 CFH+ for high-demand homes

Total residential load:

• Typical home with furnace + water heater + range + dryer: 200-300 CFH max
• Add pool heater, generator, fireplace: 400-500 CFH
• Verify meter rating supports peak load

Gas pressure

Residential gas pressure:

• Utility supplies at ~5-7 inWC (inches water column) typical for natural gas
• Some systems: 2 PSIG (regulated down at appliance)
• Propane: 11 inWC typical at appliance

Pressure regulator at the meter steps down utility pressure to house pressure. Failure modes:

• Regulator failure (high pressure to appliances)
• Pressure drop (utility-side problem)
• Frozen regulator (winter)

Cold-weather meter considerations

Outdoor meters can freeze:

• Moisture in regulator
• Cold air contracts gas (lower volume = appears lower flow)
• Regulator can ice up

Customer reports "no heat in extreme cold" - check meter first:

• Iced over?
• Buried in snow?
• Clearance per utility requirement?

Smart / AMI meters

Modern utility meters transmit:

• Hourly OR even more frequent data
• Customer accesses online
• Identifies usage patterns
• Bills more accurate

Help customer access their portal; they often don't know it exists.

Customer billing

Gas billed by:

• Therms (most US utilities): 1 therm = 100,000 BTU
• CCF: hundred cubic feet
• Conversion: 1 therm ≈ 1 CCF (varies slightly by region per heating value)

Bill components:

• Customer service charge (fixed)
• Volume charge (per therm / CCF)
• Distribution charge
• Taxes
• Possibly seasonal rate

Total cost = volume × rate + fees.

Reducing customer's gas bill

Customer asks: how to reduce?

• Lower thermostat setpoint
• Water heater temperature down to ~120°F
• Insulate hot water pipes + tank
• Fix leaks (even tiny ones add up)
• Maintain equipment (clean burners, replace filters)
• Verify equipment sized correctly (oversize fires often)
• Consider high-efficiency equipment replacement

Identifying high bills

Customer surprised by high bill:

1. Compare to prior periods (similar weather)
2. Check for usage changes (new equipment, more occupants)
3. Read meter; verify utility's reading is correct
4. Look for leaks (test as above)
5. Check equipment combustion efficiency (clock test)

Sometimes the bill is correct + customer is using more than they realize.

Working at the meter

Safety:

• Don't shut off utility meter without authorization (utility-owned)
• Customer-side shutoff valve at appliances OR at house entry
• Don't tamper with meter

Painting / landscaping around meter:

• Customer can paint meter if rust prevention is needed
• Don't bury meter
• Don't enclose without ventilation
• 3 ft clearance typically required

Common gas-meter mistakes

• Confusing CF with CCF (factor of 100)
• Confusing CF with therms
• Reading wrong direction
• Reading wrong dial
• Not isolating other appliances during leak test
• Working on gas pipe without shutting valve
• Tampering with utility meter
• Underestimating leak (small dial movement = significant gas)

When to call gas company

• Suspected leak (smell, hissing, dial spinning with appliances off)
• Meter damage
• Pressure issues
• Meter not responsive
• New service / upsize

References

• AGA (American Gas Association) meter standards
• DOT 49 CFR 192 (natural gas pipeline safety)
• NFPA 54 (National Fuel Gas Code)
• Manuall internal: Gas Pressure Testing, Combustion Fundamentals