Electronic ignition systems have replaced pilot lights for one simple reason:
Pilot lights are expensive to run. Running pilot light 24/7 can result in 5,000+ cubic feet of natural gas or 50+ gallons of propane being used every year.
How much gas does a pilot light use?
Quite a lot, actually. According to Wikipedia, “In domestic heating systems with pilot lights, it has been estimated that half of the total energy usage is from the pilot light“. We used rule of thumb approximations to calculate how much gas do pilot lights use per hour, per day, per month, and per year.
3 Quick outtakes (all calculations are summarized in the end):
- Running a pilot light for 1 hour costs about 1 cent (0.62 cent/hour for natural gas and 1.64 cent/hour for propane).
- Monthly costs of running a pilot light range from $4.49/month (natural gas) to $11.34/month (propane).
- Pilot lights that run on propane are about 2 times more expensive to run than pilot lights running on natural gas (that’s because natural gas is cheaper per produced BTU – British Thermal Unit).
Here’s the deal about pilot lights:
You won’t find them in new fireplaces, furnaces, space heaters, water heaters, gas logs, and so on. However, if you have a furnace or a fireplace that was manufactured before 2010, it will likely use a pilot light for ignition.
It is important to understand exactly how much does it cost to keep the pilot light on the fireplace, furnace, and so on. You want to know how much gas (natural gas or propane) you’re wasting, and you want to know how many dollars go down the drain every year for running pilot light.
Let’s start by calculating how much does natural gas or propane does a pilot light use per hour, month, and year. After that, we will calculate how much that amount of gas costs per hour, day, month, and year.
Note: You will find the summarized data on how much gas do pilot lights use (in gallons and US dollars) at the end of this article:
How Much Natural Gas Or Propane Does Pilot Light Use?
To calculate what quantity of gas does a pilot light use, we have to first determine how much energy does running such a pilot light use.
According to Wikipedia, a pilot light can use between “70 and 500 watts of gas power”. If we use watt to BTU converter, we get that the actual use is between 239 BTU and 1,706 BTU per hour. Those a big numbers and a big range. A standard pilot light uses about 600 BTU worth of gas every hour.
Now, let’s say that we run a pilot light for 1 hour. That consumes 600 BTU of energy. All that energy had to come from gas; how much did we burn to keep the pilot light running? We will calculate this for both natural gas and propane.
Natural Gas Expenditure (Up To Over 5,000 Cubic Feet Per Year)
Natural Gas: According to the US Energy Information Administration, burning 1 cubic foot of natural gas will produce 1,037 BTU. So we use less than 1 cubic foot; here’s how much exactly:
Natural Gas = 600 BTU (1h of pilot light running) / 1,037 BTU = 0.579 Cubic Feet Per Hour
That means that running a standard pilot light non-stop will consume:
- 0.579 cubic feet of natural gas per hour.
- 13.90 cubic feet of natural gas per day.
- 416.88 cubic feet of natural gas per month.
- 5002.56 cubic feet of natural gas per year.
That’s quite a big number. If you want to run a single standard pilot light for a whole year, you burn more than 5,000 cubic feet of natural gas.
Before we look at how much this amount of natural gas costs, let’s calculate the expenditure for propane-powered heating systems as well:
Propane Expenditure (Up To 50+ Gallons Per Year)
Propane pilot light expenditure is measured in gallons. According to the US EIA, 1 gallon of propane is equal to 91,452 BTU. We know that a standard pilot light uses about 600 BTU of energy every hour.
Here’s how many gallons of propane does a pilot light uses:
Propane = 600 BTU (1h of pilot light running) / 91,452 BTU = 0.00656 Gallons Per Hour
That doesn’t sound a lot, right? Well, if you keep a pilot light on 24/7, it will spend:
- 0.00656 gallons of propane per hour.
- 0.157 gallons of propane per day.
- 4.723 gallons of propane per month.
- 56.678 gallons of propane per year.
That’s quite a lot. If you keep a standard pilot light on all the time, it will consume more than 50 gallons of propane per year.
Now, cubic feet of natural gas and gallons of propane matter, but what most of us will understand the best are dollars. Let’s look at how much does running a pilot light actually costs:
Cost Of Running A Pilot Light (Natural Gas And Propane)
We know much natural gas and propane does a pilot light waste per hour, day, month, and year. To calculate how much does that amount of gas costs, we need to know two things:
- Price of natural gas. Price in 2020 was $10.78 per 1,000 cubic feet of natural gas (Source: EIA). That means that 1 cubic foot of natural gas costs about $0.01078 (a little more than 1 cent per cubic foot).
- Price of propane. Price in 2021 was around $2.50 per gallon (Source: EIA).
We can get how much propane does a pilot light use or natural gas simply by multiplying the quantity of gas consumed by pilot light with the price of that gas like this:
Cost Of Running Pilot Light = Gas Quantity Consumed × Price Of Gas
Example: Let’s say that we have a fireplace with a pilot light. How much does it cost to keep the pilot light on the fireplace per month? We have calculated that a standard pilot light uses 416.88 cubic feet of natural gas or 4.723 gallons of propane per month.
Let’s calculate how much do both of these gas consumptions cost:
Cost (Natural Gas) = 416.88 cubic feet × $0.01078 = $4.49/month
Let’s do the same calculation for propane:
Cost (Propane) = 4.723 gallons × $2.50 = $11.34/month
Here we have it: It costs a little less than $5/month worth of natural gas to keep the pilot light running. If our pilot light is powered by propane, we will use a little more than $10/month to keep it running non-stop.
We have calculated the costs per hour, day, month, and year for a standard pilot light and summarized them in this table:
How Much Does It Cost To Run A Pilot Light? (Summarized Table)
Here is the full table of the estimated costs of running a pilot light non-stop. We used the current standard costs of natural gas and propane (these may vary quite a bit as you know):
|Running Time:||Natural Gas Cost||Propane Cost|
|Per Hour||$0.0062/hour (Less than 1 cent/hour)||$0.0164/hour (Little more than 1 cent/hour)|
As you can see, the running costs of the pilot light are not enormous. However, they are also not insignificant and should play a factor if you’re buying a new furnace, fireplace, water heater, and so on.