Although they’re no longer as common as they once were, oil furnaces can still be a good heating option. If you do have an oil furnace, it is always a good idea to occasionally calculate how much oil it is using. Calculating oil usage not only helps you to estimate what your current heating costs are, but it can also make it easier to determine if your furnace is still working effectively or is in need of any repairs. To make things easier, here is a full overview of how to calculate your furnace’s oil usage and also why it’s important.

## Determining How Much Oil Your Furnace Uses Per Hour

In order to calculate the amount of oil your furnace typically uses, you first need to determine how many gallons it burns each hour. You should be able to find your furnace’s gallons per hour rating by looking at the manufacturer’s information plate. You can also check the unit’s spray nozzle as this will also have the gallons per hour listed on it as well.

The two main factors that determine this are the size of the unit (i.e., how many BTUs of heat it produces) and the type of oil nozzle it has. Most modern oil furnaces will use anywhere between 0.65 and 1.7 gallons over the course of one hour. However, if your unit is much older, it most likely isn’t nearly as efficient as newer units and could burn more than 2 gallons of oil per hour.

You should note that this gallons-per-hour measurement is based on the furnace running non-stop for a full hour. As a result, this number alone doesn’t tell you all that much since your furnace shouldn’t ever run for an hour straight if it is working correctly and your home is properly insulated. If you do ever find that your furnace runs for this long continuously, you will want to have it inspected since this indicates that there is some issue affecting its performance.

## Calculating How Many Hours Your Furnace Runs on an Average Day

Before you can estimate your furnace’s average daily oil usage, you will need to know approximately how many total hours it runs on a normal winter day. To do this, you will need to observe your furnace for an hour both during the warmest and coldest parts of the day. This means making note of how many minutes your furnace runs for during one hour in the mid-afternoon and for one hour around 6 a.m. when the temperature is typically coldest.

To get an accurate estimate, both observations should be made on the same day. You should also make your observations on a day when the temperature range is near the normal winter averages. If you were to make this observation on a much colder or much milder day, your calculation won’t be all that accurate since the outdoor temperature is one of the main factors that influence how much your furnace runs and thus how much oil it uses.

Once you’ve made your observations, you will then need to average the two numbers so you can then estimate the normal hourly run time across an entire day. To find the average, you need to multiply your two observations and then divide this total by two. Multiplying the average minutes by 24 then lets you calculate how many minutes the unit would run over one full day. Finally, you can divide this total by 60 to find the average hours the furnace runs in a full day.

Let’s say that your furnace ran for a total of 35 minutes when you observed it for an hour during the morning and for 15 minutes in the afternoon. This means that averaged out over a full day, the unit would run for around 25 minutes an hour. Based on this, you can then estimate that the unit would run for around 600 minutes, or 10 hours, on a normal day.

## Estimating Total Gallons of Oil used Per Day

Now that you know the approximate number of hours your furnace would run on a typical winter day, you can then move on to estimating the total number of gallons of oil it normally uses in a day. All it takes to do this is to multiply how many gallons it uses in an hour by how many hours it typically runs in a day.

Let’s say that your furnace burns 1.5 gallons of oil per hour and runs for an average of 10 hours per day. This means that it will typically burn around 15 gallons of oil on a normal winter day.

## Why Knowing How Much Oil Your Furnace Uses is so Important

Knowing how much oil your furnace typically uses in a day is essential for figuring out how often you will need to have your oil tank refilled so that you don’t ever risk running out. The average residential oil tank holds around 250 gallons. If your furnace burns around 15 gallons of oil on an average winter day, this means that a full tank would last you just over 16 full days.

In this case, you’ll want to get your tank refilled approximately every 10 to 12 days. It is important that you never wait too long as otherwise, you’ll run the risk of running out of oil should a sudden cold snap happen and lead to your furnace suddenly running much more.

It is also a good idea to check the gauge on your oil tank daily during the winter so that you always know approximately how much oil you have left. In general, you will always want to call your oil company to schedule a delivery once the gauge shows that the tank is only one-quarter full.

## How the Texas Weather Affects Oil Consumption

The fact that Texas has quite mild and warm winters compared to much of the rest of the country means it is unlikely that your furnace would ever actually burn 15 gallons of oil a day. It could happen during one of those rare extreme cold snaps, your oil usage will typically be far below this since your furnace won’t ever need to run that often.

In fact, studies have shown that when the outdoor temperature is around 50 degrees Fahrenheit, the average furnace will usually burn somewhere between 2 and 4 gallons of oil in a day. As a result, a full tank of oil will typically last for at least two months.

If you find that you’re going through much more oil than this even when the weather is mild, it is likely that either your furnace isn’t working effectively or your home isn’t properly insulated and has lots of air leaks. Either way, this is something you will want to get taken care of so that both your comfort and your bank account don’t suffer.

## Your Local HVAC Experts

If you need heating service in the Bastrop area, the team at Blue Ribbon Heating & Cooling has you covered. We specialize in furnace maintenance, repairs, and installation, and we also install, repair, and maintain heat pumps, air conditioners, and ductless mini-splits. Our team offers services for air purifiers, whole-home humidifiers and dehumidifiers, and other indoor air quality equipment as well. For more information or to schedule a service call, contact our team today.