Space Heaters

Oil Heater Room Heating Times Guide (With Size Chart)

Oil Heater Lg

You went outside for the first time in November and realized that Jack Frost is starting to nip at your nose! One of the first things you as a homeowner will think is, “it is time to get my heater out again!” or maybe you do not have one yet and wish to find the best heaters.

As you may already know, oil-filled heaters are among the best options in your home. They are made to be highly safe for those who wish to sleep with a heater or want to run errands without thinking that their home will catch on fire.

An oil-filled heater will take much longer to room the warm-up compared to other space heaters. This can take anywhere between 30 minutes to 2.5 hours for the heat to fully kick in. However, it also entirely depends on the size of a room. If you have a large living area of 340 square feet, then an oil-filled heater will take longer than if it were in an average-sized bedroom of 160 square feet. 

Although this may not be what you want to hear, oil-filled heaters have many benefits, such as being eco-friendly, quiet, and retaining heat well. We will be going over more detail on a guide of how long each heater will heat up and what you can expect in terms of space. Keep scrolling down to find all the available information on the subject! 

How Long Does It Take An Oil Heater To Heat A Room?

It can be a complicated answer when wondering exactly how long an oil heater takes to warm up a generalized area, so we researched the solution to make sure you get pretty accurate answers. Some brands will warm up quicker than others, but it is safe to note that overall, an oil-filled heater will take full effect in heating a room anywhere between 30 minutes to 2.5 hours.

Although an oil heater takes longer to heat up, rest assured that it will remain for quite a long time once the area is warm, even after you turn it off. 

That being said, we have put together a graph of some of the most popular oil-filled heaters, how many watts of usage they use, the area amount it will heat up, and a rough estimate of the length of time it will take for each brand to warm up.  

BrandWattageSquare Foot Coverage In The HeatLength Of Time For Maximum Heat Coverage
De’Longhi Oil-Filled Radiator Space Heater700-1500 watts200-300 square feetFeel heat around 20 minutes, but the full effect after 30-45 minutes
Comfort Zone® Deluxe Oil Filled Radiator600-1500 wattsMedium room (up to 1200 square feet)1-2 hours
COSTWAY Oil Filled Radiator Heater1500 wattsMedium to large rooms (216-300 square feet)1-2 hours
Pelonis Electric Oil-Filled Radiant Heater600, 900, & 1500 watts160 square feet 1-2 hours
NewAir Electric Oil-Filled Space Heater1500 wattsHeats rooms up to 12’ x 13’ (150 square feet)Up to 1 hour
Homeleader Space Heater600, 900 & 1500 wattsUp to 200 square feet1-2 hours for its entirety
Honeywell EnergySmart Electric Oil Filled Radiator1500 wattsUp to 140 square feetUp to 1 hour

How Do I Work Out What Size Heater I Need For My Room?

It is relatively easy to determine what size heater you will need for a specific room within your home. Every 10 watts of power the heater needs will heat 1 square foot of space within your home. Most heaters come at 1500 watts, especially oil-filled ones, as you can see from above, so it is safe to say that most of these will cover roughly 150 square feet.

Suppose you have a relatively large area, such as the living room. In that case, it is essential to note that if you wish to keep the entire site warm, locate it in a centralized place where the majority of people will be or get two heaters to ensure it will be up to your standards in terms of how warm you want your house to be. 

What About Cost In Electricity?

One of the many questions we get here at Heaterspace is how long it would initially cost to use a portable heater. According to Electric Choice, you can calculate it by how much electric and gas companies charge, which is, on average, 13.19 cents per kilowatts per hour (kWh).

Overall, an oil-filled heater that uses 600-1500 watts of power (or 0.75-1.5 kilowatts per hour) will cost you roughly $2.25 to $4.95 to run every hour.

Will An Oil Heater Heat A Room?

Some people may be concerned because oil-filled heaters do not use fans to blow out heat, so it might not heat a room in its entirety, right?

Oil heaters take longer to heat because they radiate through the metal columns with basins inside, allowing the heat to transfer to the oil freely around the heater itself. The oil will also come to a high boiling point that flows throughout the heater. 

As we learned from above, although it does take a while for an oil-filled heater to make a room heat up, rest assured they do work and eventually get there. That said, it is critical to purchase the right one to ensure you are getting the best value out of your investment. 

How Long Do Oil-Filled Radiators Remain Warm?

When you initially turn off the electric radiator heater, it will stay warm for a relatively long time because the oil inside the system will take a while to cool down fully. Depending on what temperature it is externally, these radiators should take anywhere between 1.5-2 hours to cool down in their entirety. 

Are Oil Heaters Efficient?

Oil heaters are incredibly efficient when it comes to heating. They can travel from room to room without issues and are nearly 100% energy efficient.  

The reason why they are so efficient is that they are using diathermic oil instead of water. The oil can absorb a lot of heat before the temperature rises. As we have already learned, it also allows the heater to remain warm, even after being shut off. 

How Long Do Oil Heaters Last?

Oil-filled heaters, when used correctly, can last between 15-20 years, given the proper care and maintenance. This means that when it is in storage, you will cover the radiator up with something, and when it is not in storage, you are keeping it out of arm’s reach instead of accidentally beating it up by bumping it into or tripping over it.

If you wish to make it last even longer, do not have the heater running 24/7. Another thing to consider is that whenever you transport it somewhere, make sure to use the wheels or lift it for better safety over your product.

Also, oil heaters can last 10-15 years if you constantly keep them running, especially at a higher temperature. If it is not covered up during storage, more dust can get on it, causing the heater to fail slightly more than if it were not.

Lastly, when children, animals, or even yourself, bump into the radiator, it will surely go out faster than if it were out of the way. 


Given all of this information with the initial question of how long an oil-filled heater would take to heat the room, given the research we did for you today, it would take 30 minutes to 2 hours to fill the space up unless it is a smaller oil-filled heater. In that case, it should take much longer unless if you were to use it for a desk setting only.

We hope you have received some enlightenment on this subject and go forth to be confident with whatever oil heater you choose for your household!


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.