3 Most Powerful Space Heaters

Today we’re going to have a look at the most powerful space heaters. In depth.

We’re going to check:

  • Which space heaters provide the most heat? (checking heaters with and without installation separately)
  • How much electric power do they consume?
  • What’s the proper way to install and use them?
  • And to round it all up: How to generate the most heat using only space heaters, but without installation?

First of all, a disclaimer: Since we’re really trying to find the absolute strongest space heaters on the market, most of the recommended products on this page are way too strong for regular living spaces.

Not just heat-wise, but also the electric power requirements are way beyond what regular US wall outlets can handle.

So, we’re going to start with recommendations for regular households (which are moderately-sized, but very strong space heaters).

And then, we’ll continue with the absolute most powerful space heaters for garages, warehouses, workshops, sheds, and building sites.

For regular households: The most powerful space heaters

So, if you found this article looking for the most powerful regular household space heater, then I recommend the following:

No installation required: Most powerful electric household space heater

US home circuits provide up to 15 Amps of current and a voltage of 120 Volts. That’s a total maximum power of

15 × 120V = 1800 Watts

A regular US wall outlet can’t handle more than 1,800 Watts.

That’s why electric space heaters usually have a maximum power rating of 1,500 Watts.

You just can’t get any stronger. In Europe, the situation is different. There, wall outlets can handle almost twice the power. So, electric space heaters rated at 2,500W are very common.

In the US, the most powerful electric household space heater is this DeLonghi oil-filled radiator (click here to view it on amazon).

Actually, calling it the “most powerful” is misleading, since there are hundreds of other space heaters rated at 1,500W. But I found not a single (trustable) model that is rated higher.

delonghi oil-filled radiator

So, with electric household space heaters you only get so far. The electric circuit is usually too weak to handle more.

But there’s a way around it:

No installation required: Most powerful propane space heater

You can work around electric limitations by simply using a propane heater instead of an electric heater

My favorite indoor-safe portable propane heater is this Mr. Heater Big Buddy propane heater (click here to view it on amazon).

With 18,000 BTU (British Thermal Units) of heat output per hour, which equates to a whopping 5,275 Watts of heating power, the Mr. Heater Big Buddy is more than three times as powerful as a regular electric space heater.

mr heater buddy propane heater

Mr Heater propane heaters are my favorite propane heaters and objectively one of the safest portable propane heaters you can get.

There are, of course, more choices than just the Mr. Heater portable propane heaters. Later in this article, we’ll also check out some powerful propane space heaters you can install to the wall (which output even more heat).

For (very) large spaces: Most Powerful Electric Space Heaters (that require installation)

Now, let’s have a look at the real Champions League of powerful electric space heaters.

1. Most powerful: Dyna-Glo Dual Power (15,000 Watts)

The most powerful electric space heater is this Dyna-Glo Dual Power 15,000 Watts heater (click here to view it on amazon).

This electric space heater is so powerful, it needs to run on a dedicated circuit and it requires hard wire installation. 

So, to get this space heater running, you’ll need the hand of a professional. 

space heater dynaglo 15000 watts
This Dyna-Glo heater blasts a whopping 15,000 Watts!

2. Ideal for warehouses and garages: Qmark space heater (10,000 Watts)

The second most powerful electric space heater is this 10,000 Watts Qmark space heater (click here to view it on amazon).

This unit draws 42 Amps from a 240-volt circuit. So, this space heater is also too strong for regular household circuits.

This space heater is also capable of running on a three-phase electrical system. Usually, these are found in industrial settings. Or, you can, of course, have someone install that in your home.

For installation, you should ideally hire an electrician.

That’d also be better insurance-wise in case of an accident.

3. Requires little installation: NewAir Space Heater (4,800 Watts)

This 4,800 Watts NewAir space heater (click here to view it on amazon) requires less installation effort compared to the other heaters in this list.

It is the only corded heater, meaning you can plug it into a wall outlet.

The drawback: The wall outlet has to be 240 Volts.

So, if you don’t have a 240 Volts outlet, you should install one or hire a technician to do it for you.

But aside from that, this space heater is ready to go.

Although its power pales in comparison to the other powerful heaters in this list, this model is still three times as strong as regular 1,500 Watts space heaters.

So, that’s more than enough for most spaces!

Even more powerful: Most Powerful Propane Space Heaters

Propane space heaters can output even more heat than electric space heaters. And additionally, they don’t require you to upgrade your electric circuitry.

So, let’s also have a look at the strongest propane heaters.

The most powerful propane heaters are all vented. So, they also need installation. But the installation is much simpler than that of heavy-duty electric heaters.

Recommended strong propane space heater: Mr Heater Big Maxx

The strongest propane space heaters are the Mr. Heater Big Maxx models.

I’ve already written about them in this article: 3 Best Vented Gas Heaters

They come in different sizes (depending on heat output).

The strongest model is this 80,000 BTU Mr Heater Big Maxx (click here to view it on amazon).

That’s equal to over 23,400 Watts of heating power!

You can also get the smaller variant, the 50,000 BTU Mr Heater Big Maxx (click here to view it on amazon).

I feel weird calling this one the “smaller variant”. With 50,000 BTUs this heater likely heats any space you need heated.

It produces as much heat as the most powerful electric heater we checked earlier.

The Mr Heater Big Maxx models are great for heating construction sites, large garages & workshops!

How to get the most heat without installation?

Most of the heaters recommended in this article require installation, because of their power requirements or because they need to be vented.

If installation is not an option for you, but you still want to produce the most heat possible, I recommend combining independent heaters.

While, in a regular US household, it’s usually not possible to run two electric space heaters at once, you can run two portable propane heaters at once.

Or you can run one electric space heater and one propane heater.

Or three propane heaters.

Do whatever suits your heating needs.

The rule is: Don’t run more than one electric space heater simultaneously.

You can add as many propane heaters as you like.

To do that, I recommend getting the DeLonghi electric heater recommended earlier and the Mr Heater Big Buddy propane heater.

One electric space heater combined with a strong portable propane heater will add up to:

1,500 Watts + 18,000 BTU/h ≈ 1,500 Watts + 5,275 Watts = 6775 Watts of heating power

infrared heater front view
My infrared heater, combined with the Mr Heater Buddy (in the background)

More ideas to heat large spaces (without needing the absolute strongest heater)

Running a large space heater on full power for an entire workday of 8 hours or possibly even longer can get very costly very quickly.

The 15,000 Watt electric space heaters recommended earlier, for example, can easily add $100 to your monthly electricity bill.

Although propane is a bit cheaper, if you run the largest heaters on full power, you’ll run through propane tanks quickly.

A 100lb propane tank, for example, an 80,000 BTU heater, for example, will only last for 22 hours before it is empty.

Insulate to Elevate

Insulation is a game-changer when it comes to heating efficiency.

By adequately insulating walls, floors, and especially the ceiling, you reduce the rate at which heat escapes.

Double-glazed windows can also make a significant difference. With good insulation, even a less powerful heater can do wonders.

Seal the Leaks

Drafts from windows, doors, and even electrical outlets can be significant heat drainers.

Sealing gaps with weather stripping or using draft stoppers can help maintain a consistent indoor temperature, reducing the amount of work your heater has to do.

Zone Heating

Why heat the whole house when you’re only using a few rooms? Focusing on heating only the spaces you’re using can reduce power requirements.

For example, rooms with high ceilings are best heated using infrared heaters.

They radiate heat in just one direction and feel much warmer in large spaces.


In a nutshell, the most powerful space heaters for regular households are the DeLonghi oil-filled radiator, maxing out at 1,500 Watts, and the Mr. Heater Big Buddy propane heater, offering 5,275 Watts.

For larger spaces, the Dyna-Glo Dual Power is the strongest electric space heater with 15,000 Watts, but it requires professional installation.

If you’re looking to heat a space without installation, your best bet is to combine an electric heater with a propane one. This will give you around 6,775 Watts of heating power, more than enough for most spaces.

Always remember, running multiple electric heaters on a standard U.S. circuit is a no-go, but you can mix and match with propane heaters as much as you like.

Choose wisely based on your specific needs and always prioritize safety, especially when dealing with such powerful units.