The 20% Rule of Propane Orders

What You’ll Learn

At what point should I order propane?

You should always schedule a propane delivery before your tank level drops below 20%.

Ordering early helps prevent system shutdowns, avoids mandatory leak checks, and protects you from costly winter delays or emergency service fees.

In this blog:

• The 20% Rule of Ordering Propane
• How to Read Your Propane Tank Gauge
• When to Check Your Propane Gauge
• Automatic Delivery: The Stress-Free Way to Avoid Running Low

Your furnace has been chugging away.

Thanks to its hard work, you’re nice and cozy inside your home despite the freezing winds tossing the trees around outside.

You checked your tank a few days ago, and it was 40%, so you’re considering calling your propane provider for a refill.

Or should you wait? Does it really matter?

If you want to avoid an emergency delivery, knowing when to order a refill matters.

In this guide, you’ll learn how to read your tank gauge correctly and order before you hit 20% to protect your home from system shutdowns, leak checks, winter delays, and costly service calls.

The 20% Rule of Ordering Propane

The 20% rule is simple: Always order propane before your tank falls below 20%.

You may wonder, “Why not wait until 10%? Or 5%? Wouldn’t that maximize the delivery?”

The truth: falling below 20% triggers problems that are far more expensive and inconvenient than any extra space in your tank.

Here’s what the 20% rule protects you from:

1. System Shutdown

When propane levels drop too low, the pressure inside the tank may fall below the threshold needed to power your furnace, boiler, water heater, or stove.

Even if there is technically propane left, your system can stop working.

Low-pressure shutdowns are especially dangerous in winter because a mid-cycle furnace shutdown can lead to:

• Furnace lockouts
• Safety control trips
• Systems that require manual resets by a technician
• In severe cold, frozen pipes or other home damage

These issues can turn a simple refill into an emergency service call.

2. Mandatory Leak Test & Line Bleed

If your tank runs out of propane—or gets close enough that pressure is lost—your propane provider must perform a mandatory leak check before refilling and reactivating your system.

This is a safety requirement, not an optional service.

Leak checks:

• Take additional time
• Have additional costs
• Delay your heat coming back on

And if your tank runs completely empty, a technician must also bleed your gas lines to remove trapped air before your system can restart.

3. Equipment Damage

Low propane levels can cause furnace lockouts, soot buildup, pilot light failure, and regulator strain.

4. Winter Service Delays

In Pennsylvania, demand for propane spikes whenever temperatures drop.

When winter storms arrive, companies prioritize customers with emergencies, not standard refills.

If your tank goes below 20% during a cold spell, you may face:

• Longer wait times for delivery
• Emergency or off-route delivery fees
• Uncomfortable hours (or days) without heat

How to Read Your Propane Tank Gauge

Every above-ground propane tank—from 120-gallon cylinders to 1000-gallon residential tanks—comes equipped with a built-in gauge located under the dome lid on top of the tank.

This gauge doesn’t tell you gallons; instead, it reads percentage full.

Here’s how to understand what you’re looking at:

1. Lift the dome lid on top of the tank

Inside, you’ll see the fill valve, service valve, and the round gauge with a small needle. The gauge looks similar to a speedometer.

2. Read the needle position

The needle points to a percentage—typically between 0% and 80%.

Why 80%? Because propane expands with temperature, tanks are never filled to 100%. The industry-standard maximum is 80% to allow safe expansion space.

3. Use the reading to estimate your supply

Common readings look like:

80% — Just filled

60% — Plenty of fuel

40% — Time to monitor more closely

20% — Time to order your next delivery

Below 20% — Urgent! Call immediately

Simple and reliable, this gauge is your best friend during a Pennsylvania winter.

When to Check Your Propane Gauge

Pennsylvania weather swings can be dramatic. Your gauge can drop quickly in winter, and more slowly in spring or fall.

Here’s how to stay ahead:

Check once a month from April to October

Usage is low, but keeping an eye on levels helps you plan ahead before winter.

Check once a week from November to March

Cold nights add up fast. A tank can drop 20–30% in a single cold week, depending on household size and appliances.

Check after any major household change

Examples include:

• Hosting holiday guests
• Installing new propane appliances
• Adding a generator

Your usage pattern may shift without you realizing it.

Automatic Delivery: The Stress-Free Way to Avoid Running Low

Many Pennsylvania homeowners eventually decide they don’t want to check their propane gauge at all, and they don’t have to.

With automatic delivery, your propane provider handles everything for you:

• Tracks your usage
• Estimates consumption based on temperature and degree-day data
• Schedules deliveries before you ever reach 20%

This means no more checking gauges, guessing, or risk of running out and getting hit with emergency fees.

Automatic delivery is particularly valuable for busy families, seniors, homes with high winter usage, and anyone relying on propane for primary heat.

Your provider keeps your tank full, and you stay warm—without lifting a finger.

Don’t Get Left Out in the Cold

Don’t wait for your tank to run low—or for winter to arrive. Make propane simple, predictable, and stress-free.

Become a Kauffman Gas customer today and opt into automatic delivery to keep your Pennsylvania home warm year-round.

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