How to Choose the Right Propane Tank Size for Your Tiny House

Quick answer

Choosing the right propane tank size for your tiny house starts with listing your appliances—fridge, heater, stove, water heater—and estimating their hourly BTU ratings. Multiply each by daily hours of use, add 20% for cold climates, then divide by 91,500 (BTUs per gallon) to find your daily gallons. A 20 lb tank holds ~4.7 gallons; a 100 lb tank holds ~23.6 gallons. Most tiny houses use 20–100 lb tanks, refilling every 1–4 weeks depending on usage and weather.

For precise planning, track your actual usage over a week in different seasons. This avoids running out mid-winter or overpaying for unused capacity. If you’re new to off-grid propane, start with a smaller tank and monitor fill frequency—it’s easier to upgrade later than to store excess propane safely.

For a complete safety and sizing system, Off-Grid Propane for Tiny Houses: Field-Tested Safety Systems for Mobile Living walks you through real-world setups, including tank placement, leak detection, and backup plans.

Step 1: List your propane appliances and their BTU ratings

Start by identifying every propane-powered device in your tiny house. Common ones include:

• Propane refrigerator (800–1,500 BTU/hour)
• Space heater (5,000–30,000 BTU/hour)
• Stove or cooktop (5,000–15,000 BTU/hour per burner)
• Water heater (30,000–50,000 BTU/hour)
• Backup generator (varies widely; check manual)

Check appliance labels or manuals for exact BTU ratings. If you can’t find them, use the mid-range values above as a starting point. For example, a typical tiny house stove might use 10,000 BTU/hour per burner, and a small heater might use 10,000 BTU/hour.

Step 2: Estimate daily usage hours for each appliance

Think about how long you use each appliance each day. Be realistic—don’t assume you’ll never cook or heat water. Here’s a sample daily estimate for a couple in a cold climate:

• Stove: 1 hour (two burners at 10,000 BTU each = 20,000 BTU/hour total)
• Heater: 8 hours (10,000 BTU/hour)
• Water heater: 1 hour (40,000 BTU/hour)
• Refrigerator: 24 hours (1,000 BTU/hour)

In warmer months, you might use the heater only 2 hours a day or not at all. Adjust your estimates based on your climate and habits.

Step 3: Calculate daily BTU consumption

Multiply each appliance’s BTU rating by its daily usage hours, then add them up. Using the example above:

This household uses 164,000 BTUs per day in cold weather.

Step 4: Adjust for climate and efficiency

Propane appliances work harder in cold weather, reducing efficiency. Add 20% to your daily BTU total if you live in a climate with freezing winters. In the example above, 164,000 BTUs becomes 196,800 BTUs (164,000 × 1.2).

If your appliances are older or poorly maintained, they may use more propane. Regular cleaning and servicing help keep them efficient.

Step 5: Convert BTUs to gallons

Propane contains about 91,500 BTUs per gallon. Divide your adjusted daily BTU total by 91,500 to find your daily propane usage in gallons. In the example:

196,800 BTUs ÷ 91,500 = ~2.15 gallons per day

Over a week, that’s about 15 gallons. Over a month, it’s ~65 gallons.

Step 6: Choose a tank size based on refill frequency

Propane tanks are measured by weight, but their capacity is in gallons. Here’s a quick reference:

For the example household using ~2.15 gallons per day, a 100 lb tank (23.6 gallons) would last about 11 days. A 30 lb tank (7.1 gallons) would last about 3 days. Most tiny house owners prefer 30–100 lb tanks for a balance of convenience and space.

If you’re unsure, start with a 30 lb tank and track your usage. You can always upgrade later. Just remember: larger tanks require more space and proper ventilation.

Step 7: Plan for storage and safety

Propane tanks must be stored outdoors, away from doors, windows, and ignition sources. Check local codes for exact requirements—some areas limit tank size or placement. For example, some municipalities cap residential tanks at 100 lbs or require them to be at least 10 feet from buildings.

If you’re mobile, secure your tank with straps or a mounting bracket to prevent movement while driving. A loose tank can become a dangerous projectile.

Ventilation is critical. Propane is heavier than air and can pool in low areas, creating a fire or explosion risk. Never store tanks in enclosed spaces like sheds or under decks.

If you’re new to propane or want a foolproof system, Off-Grid Propane for Tiny Houses: Field-Tested Safety Systems for Mobile Living covers tank placement, leak detection, and emergency protocols in detail. It’s especially useful if you’re designing your system from scratch or troubleshooting an existing setup.

Step 8: Test and adjust your setup

Once you’ve chosen a tank, monitor your usage for the first few weeks. Keep a log of fill dates and weather conditions. This helps you spot trends and adjust your estimates. For example, you might find you use more propane on cloudy days or when hosting guests.

If you’re running out too often, consider upgrading to a larger tank or adding a second one. If you’re refilling less than once a month, you might be able to downsize and save space.

Common mistakes to avoid

• Underestimating cold weather usage: Heaters and water heaters work harder in freezing temperatures. Always add a 20% buffer for winter.
• Ignoring appliance efficiency: Older or dirty appliances use more propane. Clean burners and vents regularly.
• Storing tanks indoors: Propane must be stored outside, away from ignition sources. Never keep tanks in enclosed spaces.
• Skipping leak checks: Use soapy water to test connections for bubbles. If you smell gas, turn off the tank and ventilate immediately.
• Choosing a tank that’s too large: Larger tanks take up more space and may not be allowed in some areas. Start small and upgrade if needed.

Who this ebook is for

If you’re setting up a propane system for the first time, Off-Grid Propane for Tiny Houses: Field-Tested Safety Systems for Mobile Living is for you. It’s ideal for:

• Tiny house owners who want a step-by-step guide to sizing, installing, and maintaining their propane system.
• People who are new to off-grid living and need clear, practical advice on propane safety and efficiency.
• Mobile tiny house dwellers who need solutions for securing tanks and managing propane while on the road.
• Anyone troubleshooting an existing propane setup or looking to upgrade their system for better performance.

The ebook includes real-world examples, safety checklists, and troubleshooting tips to help you avoid common mistakes and build a system that works for your lifestyle.

Final tips for choosing the right propane tank size

• Start small: It’s easier to upgrade later than to store excess propane. A 30 lb tank is a good starting point for most tiny houses.
• Track your usage: Keep a log of fill dates and weather conditions to refine your estimates.
• Plan for worst-case scenarios: Add a 20% buffer for cold weather and unexpected usage.
• Prioritize safety: Store tanks outdoors, away from ignition sources, and test for leaks regularly.
• Consider your lifestyle: If you travel often, a smaller tank might be more convenient. If you’re stationary, a larger tank could save you refill trips.

For a complete guide to off-grid propane, including safety systems and real-world setups, Off-Grid Propane for Tiny Houses: Field-Tested Safety Systems for Mobile Living is a practical resource to help you build a system that’s safe, efficient, and tailored to your needs.

Frequently asked questions

How long does a 20 lb propane tank last in a tiny house?

A 20 lb propane tank holds about 4.7 gallons. In a tiny house with a stove, heater, and water heater, it typically lasts 2–4 days in cold weather, depending on usage. In warmer months, it might last a week or more. Track your actual usage to get a precise estimate.

Can I use a 100 lb propane tank in my tiny house?

Yes, many tiny house owners use 100 lb propane tanks. They hold about 23.6 gallons and last 1–2 weeks in cold weather for most setups. Check local codes for storage requirements—some areas limit tank size or placement. Always store tanks outdoors, away from ignition sources.

How do I know when my propane tank is empty?

Most propane tanks have a gauge, but they’re not always accurate. A better method is to weigh the tank. A 20 lb tank weighs about 18 lbs empty and 38 lbs full. Subtract the empty weight from the current weight to find how much propane is left. For example, a 20 lb tank weighing 25 lbs has about 7 lbs (or ~1.6 gallons) of propane remaining.

What’s the best propane tank size for a tiny house on wheels?

For mobile tiny houses, 20–40 lb tanks are popular because they’re easy to transport and refill. A 30 lb tank (7.1 gallons) is a good balance between capacity and convenience. If you use a lot of propane, consider mounting two 30 lb tanks side by side. Always secure tanks with straps or brackets to prevent movement while driving.

How do I calculate propane usage for a propane refrigerator?

Check the refrigerator’s manual for its BTU rating—most tiny house fridges use 800–1,500 BTU/hour. Multiply the rating by 24 (hours in a day) to find daily BTU usage. For example, a 1,000 BTU/hour fridge uses 24,000 BTUs per day. Divide by 91,500 (BTUs per gallon) to find daily propane usage: 24,000 ÷ 91,500 = ~0.26 gallons per day.

Is it safe to store propane tanks inside my tiny house?

No, propane tanks must always be stored outdoors. Propane is heavier than air and can pool in low areas, creating a fire or explosion risk. Store tanks in a well-ventilated area, away from doors, windows, and ignition sources. Check local codes for exact requirements—some areas require tanks to be at least 10 feet from buildings.