How Long Does A 250-Gallon Propane Tank Last For A House?

250-gallon propane tanks are primarily used for winter heating. With a 250-gallon residential tank, you can heat up your entire house. The key question here is this:

How long does a 250-gallon propane tank last for a house?

Here’s the short answer:

A 250-gallon propane tank lasts for anywhere between 26 days to 7 months and 2 days. That’s quite a wide range. The longevity of a 250-gallon propane tank depends on use (how much propane per day you burn). This is indirectly connected with how big a house you want to heat with a 250-gallon propane tank.

If you want to use a residential propane tank for heating, you have to calculate how long will it last. There are two ways how to calculate that (we use both of them further on), namely:

1. By heating demand. This is the harder way; you have to estimate your average heating demand in the 6 winter months. Example: A house with 20,000 BTU heating demand will burn throughout a 250-gallon propane tank in 37-38 days.
2. By house size. This is the easier way. Obviously, the 250-gallon propane tank will last much longer heating a small 500 sq ft house than heating a big 4,000 sq ft house. If you check the analysis of how long do propane tanks last here, you can see that an average US household (2,200 sq ft house) uses about 750 gallons of propane for heating in 6 winter months (October through March). We can use these average propane heating consumption to calculate how long will a 250-gallon propane tank last for any house size.

   

We also need to take into account that a full 250-gallon tank holds 200 gallons of propane. This is the 80% rule for all residential tank sizes; it is a safety measure.

Let’s first look at how you can calculate how long will a 250-gallon propane tank last for heating via heating demand. After that, we will also look at how long will this tank last for 500, 1000, 1500, 2000, 2500, 3000, 3500, and 4000 sq ft houses:

Method 1: How Long Will A 250-Gallon Propane Tank Last (By Heating Demand)

Here we will determine how much energy does a 250-gallon propane tank hold. Then comes the tricky part – evaluating how much energy you need for heating. Based on this, we can calculate how long should a 250-gallon propane tank last.

1 gallon of propane contains 91,500 BTU of heating energy. In a full 250-gallon propane tank, we have 200 gallons of propane. Here is how much energy such a 250-gallon propane tank hold:

Energy Content (250-Gallon Tank) = 200 Gallons × 91,500 BTU/Gallon = 18,300,000 BTU

That means that a 100% full 250-gallon propane tank holds almost 20 million BTU of heating energy.

Now we need to determine how many BTUs we use to heat our home. Small homes require as little as 5,000 BTU/h and the biggest homes require more than 50,000 BTU/h. This is the average hourly heating output in the 6 winter months (it’s notoriously difficult to evaluate; that’s the primary reason why we use the following easier Method 2 for this calculation).

Example: Let’s say we have a house that requires 15,000 BTU of heat every hour. We know that the 250-gallon propane tank holds 18,300,000 BTU of energy. How long will this energy from the 250-gallon propane tank last? Here’s how we can calculate that:

How Long Will 250-Gallon Tank Last = 18,300,000 BTU / 15,000 BTU/h = 1,220 h =

50 Days And 20 Hours

As you can see, for such heating demand, a 250-gallon propane tank will last 10 days shy of 2 months.

We have calculated how long will a 250-gallon propane tank based on different heating needs. Here is the full calculated table:

Heating Need (BTU/h):	250-Gallon Tank Lasts For:
5,000 BTU/h	153 days
10,000 BTU/h	76 days
20,000 BTU/h	38 days
30,000 BTU/h	25 days
40,000 BTU/h	19 days
50,000 BTU/h	15 days

Admittedly, it’s very hard to evaluate the heating need precisely enough. That’s why we use an easier method to determine how long will a 250-gallon propane tank last (based on house size):

Method 2: How Long Will A 250-Gallon Propane Tank Last For 500-4,000 Sq Ft Houses

Here we use average US propane consumption for heating per household data from Statista. In short, on average, a US household (2,200 sq ft) uses about 750 gallons of propane for heating during the 6 colder months (October through March).

That means that we, on average, need about 0.341 gallons of propane for heating 1 sq ft of our house. To illustrate, 1 gallon of propane is equal to 4.25 lbs; we need about 1.45 lbs of propane per square foot for heating.

With this, we can get a good estimate of how long will a 250-gallon propane tank last for any house size.

Example: Let’s say we have a 1,500 sq ft house and use a 250-gallon propane tank for heating. We know that it holds 200 gallons of propane, when full, and that we require about 0.341 gallons of propane per square foot to keep our house warm. Let’s first calculate how much propane we need for heating in 6 colder months;

How Much Propane (6 Months) = 1,500 sq ft × 0.341 gallons / sq ft  = 511.5 Gallons

That means we will need 511.5 gallons in total for heating an average 1,500 sq ft house. This is a 6-month worth of propane.

Now, a 250-gallon propane tank holds 200 gallons. If we need 511.5 gallons for heating, we will need to refuel the propane tank twice per season. What is more, we can now calculate how many months/days the 250-gallon propane tank is good for like this:

How Long Will 250-Gallon Tank Last = (200 gallons / 511.5 gallons) × 180 Days = 70.4 Days = 2 Months, 10 Days, 10 Hours

Here you have it; a 250-gallon propane tank will be able to heat an average 1,500 sq ft house for more than 2 months.

We have calculated how long will this size of propane tank last for different house sizes. Here is the full calculated table: