space heater not blowing hot air

Space Heater not Blowing Hot Air (How to fix it)

Your space heater is not blowing hot air and you don’t know how to fix it? In this article, we are going to go through potential causes. Don’t worry, it’s not going to be too technical.

And after reading this, you will know exactly how you can fix your issue.

Quick answer: When a space heater blows cold air or no air at all, it is usually due to a hardware failure. Some part of the electronic circuitry is likely broken. If your space heater does not blow air at all, it is likely that either the fan is broken or it does not receive enough power. Usually, fixing a space heater yourself is not worth it and dangerous. Instead, just buy a new one.

What you should do in case your heater does not blow hot air is mostly a philosophical question. You have two options. Either you replace or you repair your heater.

While replacing your heater is quick and easy, fixing it will save you some money.

Possible causes for your space heater not blowing hot air

In the following sections, we will have a look at the possible technical causes of your space heater not working.

Also, in each section, I give advice on how to approach the issue.

Broken or blown electronics

In the electronics of a space heater, many things can break. This includes fuses, resistors, capacitors, complex chips (integrated circuits), and many more.

If you have a good understanding of the electronics of a space heater, you can fix such an issue yourself. All you need to find the root cause is a multimeter to measure the voltages.

However, one question arises. If you measure voltages, how do you know if the voltages are correct?

This is hard to know when you don’t have the hardware plans of the manufacturer which describe the exact voltages and resistances in the circuit.

So, troubleshooting a broken space heater with a multimeter alone is oftentimes cumbersome. You have to measure voltages across the circuit and figure out yourself how the actual voltage values should be.

Oftentimes this is a matter of training and experience. Detecting hardware failure by measuring alone is therefore mostly too hard if you are not a technical professional.

Detect broken electronics by sight

From my experience, there is a much more reliable way to detect faults in electronic circuitry. All you need is a pair of good eyes.

Open your space heater and look carefully at all the electronic circuit parts inside. Oftentimes, when a part is blown, you can instantly see it.

Usually, there are burn marks around blown parts. Another frequent issue could be that a leg of a part is broken off. Or a part could be hovering above a connection without contact.

To discover broken off legs or “hovering” legs you need to look very carefully. A magnifying glass and a desk lamp is helpful in this case.

How to fix broken electronics in a space heater

To fix blown or broken parts you need a soldering iron and soldering skills. Also, you will need to replace the broken part. Find a matching piece online and purchase it.

To find the right replacement parts, you need to google the letters and numbers you see imprinted on the part. For resistors and capacitors, you need to look for parts online with matching color bands. For SMD (Surface Mount Device, or in plain English: the very small) parts, finding replacements is harder since resistors and capacitors of different ratings all look alike. 

When you find the right replacement part online, order it and replace it in the electronic circuitry of the space heater.

Generally, fixing space heater electronics yourself is only recommended if you are experienced in electronics and you know how to properly solder.

Alternatively, hire someone to fix the heater for you. But this is almost guaranteed to be as expensive as buying a new heater. Also, arranging someone and waiting for the issue to be resolved takes time and is usually not worth it.

Broken heating element

Another potential issue could be a broken heating element. Inside each space heater, there is a heating element that produces the heat. For electric space heaters, this is usually a heater coil (made of metal), a ceramic heating element, or an infrared heating element.

In case you have an infrared heater, it is very easy to check if your infrared heating element is broken. The reason is that the heating element of an infrared heater is always exposed and therefore easy to check.

Infrared heating elements usually glow orange-red. The light you see is not infrared. It is just the small visible part of the heat radiation. Anyways: If you turn an infrared heater on, you immediately see it glowing.

If your infrared heater doesn’t glow, that means the heating element does not receive enough power or is broken.

Other (oftentimes cheaper) electric space heaters have a metal heating coil. This coil also starts glowing bright orange-red. The difference is just that for some heaters it is embedded into the space heater’s body.

This is the case for Dyson heaters (and many other brands) and for all oil-filled radiators. In case you have an oil-filled radiator, it’s next to impossible to open the heater and fix the issue (there will be oil all over the place). For other electric space heaters with a metal heating element, you will have to open the case and see if the space heater gets hot when you turn it on.

How to fix a broken heating element

In any case, a broken heating coil is hard to fix. You would have to replace the heating coil with a matching replacement part. And matching replacements are hardly available and difficult to find. In the best case, you can order replacements directly from the space heater manufacturer.

If you are knowledgeable in electronics, you can also bypass the heating coil with a thick wire.

This is, obviously just a workaround and significantly more dangerous than an actual heating coil. Also, you should only do it if multiple heating coils are present in your space heater. I don’t advise this method but it is a possibility.

A heating element is, in the end, just a piece of thick wire. 

Generally, replacing parts in electric space heaters should be done by professionals. The cost of hiring someone to fix it for you makes the repair hardly worth it. Mostly it is better to just get a new space heater.

You can spend the time you save by just buying a new heater on something that makes you happy.

Broken thermostat

Another possible cause of your space heater blowing cold air could be a broken thermostat.

A thermostat controls the temperature your space heater generates. Essentially, a thermostat is a simple feedback loop.

“A thermometer is something that measures the temperature; a thermostat is something that tries to maintain the temperature (keep it roughly the same).”

explainthatstuff.com

How a thermostat works

The space heater draws power from a wall outlet and converts it to heat using an electric heating element (infrared, ceramic, wire). While it’s heating, the thermostat constantly measures the present temperature using a built-in thermometer.

Then the thermostat inside your space heater compares the current temperature with the desired temperature set in the thermostat control. Usually, you set the thermostat temperature using a knob or via a digital display.

When the thermostat control notices the current temperature is higher than the desired temperature, it shuts the heating power off. But it keeps measuring the temperature.

Once your room temperature drops below the desired temperature, the heater starts heating again.

This is called a two-point control because there are two points at which the space heater operates: Heat on, heat off.

There are also more advanced thermometer control algorithms where heat output is smoothly lowered or increased in order to reach the target temperature. But this is out of scope here.

Since a thermostat is an electric control, it consists of multiple components. The two most important are the control unit which generates the “heat output suggestions” and the sensor unit, which in this case is a thermometer.

Therefore, when a thermostat is broken, there are two possible causes:

  • the thermostat control itself
  • the thermometer sensor

How to fix a broken thermostat

Both of these could be broken. In the end, again, this problem reduces to an electronic fault. 

And you need to understand the feedback loop of the thermostat in order to fix it. In case your space heater is not blowing hot air, the thermostat believes that the current temperature is higher than the desired temperature

Therefore it is likely a fault in the thermometer. Electric thermometers are usually temperature-sensitive resistors. But in case the fault is in the control itself, it is likely an issue with an integrated circuit chip, which needs to be replaced.

If you know what you do, you can try and fix this issue yourself. Else, just save yourself some time and just get a new heater.

Clogged air filter

A really common reason for not heating space heaters is clogged and dirty air filters. Check if your air filter is clogged with dust.

When the air filter inside your space heater is clogged, two scenarios can happen.

The first scenario is that your heater is actually producing heat and everything is working fine. Except the clogged air filter prevents the fan from blowing the hot air out. The air channel is blocked.

The other scenario is that your space heater does not blow hot air, but cold air instead.

In this case, the heat generated inside the space heater activates the overheat protection and turns off the heater. Then, it could be that your space heater blows cold air only.

In any case, here’s how to fix a clogged air filter:

How to fix a clogged air filter

Open the space heater and remove the air filter. This procedure is different for each space heater, so you have to find for yourself which screws you have to open and where the air filter is located. Remember to unplug the heater before opening it.

Then remove the dust on the air filter and on the fan itself using a brush. If you don’t have a brush, you can oftentimes also pull the dust off with your fingers.

Important note: Don’t wet clean the air filter and the fan. Everything has to stay bone dry. The reason is that bacteria accumulate on your air filter. Your air filter is a perfect breeding ground for microorganisms. When you clean it with water, you “activate” these bacteria and they start growing. 

When you turn your space heater on after wet cleaning it, it will start stinking badly. Also: Who wants to blow bacteria into their home?

Therefore remember: Only dry clean air filters!

Defective fan

If your heater does not blow air at all and the air filter is not clogged, the fan itself might be broken.

In this case, you should check if the heater’s body gets warm. Because if only the fan is defective, but the heating element still works, then heat is still produced.

The heat is just not distributed in your room because your heater does not blow the hot air out.

In case you have an old heater and its fan is defective, it gets especially dangerous. The heat that is not distributed is kept inside the heater and causes the heater to overheat. Modern heaters immediately turn off once they sense overheating. But old heaters sometimes don’t.

The reason is that old heaters sometimes don’t have built-in overheat protection. Therefore they don’t “notice” that they are overheating and might not turn off.

The accumulated heat in your space heater then becomes a safety threat. In the worst-case, your heater could catch flames and cause a house fire.

If your heater gets warm and it’s just not blowing hot air because the fan is broken, then shut off your heater instantly and stop using it.

It can catch fire anytime.

If you are familiar with electronics, you can fix this yourself by checking if the fan receives enough voltage.

In case the fan receives sufficient power, but it does not blow hot air, then you need to replace it with an equivalent fan with similar or ideally the same ratings.

Replacing a fan is something you could do yourself, given you enjoy electronics and you have some basic knowledge. This fix is not too dangerous (as compared to fixing the heating element yourself). A layman could do it.

The fan inside a space heater usually does not directly connect to high voltages and therefore the danger during and after a self-made fix is comparably small.

In any case, you can not keep using the heater if it produces heat but it does not blow the hot air.

If you don’t feel confident fixing the issue yourself, buy a new heater.

How to fix your space heater not blowing hot air

There are always two approaches to fix your space heater not blowing hot air. One approach is rather obvious. It is fixing the electronics. The other approach is A LOT less troublesome. Let’s have a look at the difficult method first.

Troubleshoot the electronics and replace broken parts

To fix the electronics, you need to be knowledgeable in how the space heater works and you need a good sense of electronics as well.

Also, you need a set of tools consisting of a multimeter (to measure voltages and resistances), screwdrivers, and a soldering iron. With the screwdrivers, you open the heater case. With the soldering iron, you can replace the damaged parts.

Aside from that, you need a pair of good eyes. Having good eyes is very handy when troubleshooting issues and finding broken parts in the electronic circuitry. Oftentimes you can see the issue by simply looking at the circuit board. Some parts might be blown off or damaged.

Once you find the broken part, you need to research which properties it has (resistances, voltage ratings, etc.) or search for it online using the number written on the part. This, however, only works for bigger chips.

Then you need to replace it by soldering. If you are familiar with soldering: Great!

Else, I recommend this video for learning:

The trouble-free method to fix a broken heater

This method is a little philosophical. But I like it anyways. Oftentimes, people stress out over little things in life. Such as “How do I fix my heater blowing cold air?”.

But oftentimes, the trouble is not worth your time. Instead of spending money to get the right tools and replacement parts, or even hire an electrician, it is usually best to just go ahead and dump your space heater.

Get a new space heater. Broken heaters are a much higher threat to your home safety than new ones. Broken heaters cause fires. Especially when you repair them incorrectly.

Yes, you might save $100. But you will waste hours or even days figuring out the source of the issue. And mostly, your time is worth more than that. 

Simply get a new space heater and stop worrying.

I recommend you go ahead and check out my recommended space heaters page (click here to see it). Scroll down and click on one of the heater types you like to see a review of my personal favorite space heater in each category.

Conclusion

Wow, this article really went in-depth! We covered lots of ground and I hope you learned something.

Usually, when your space heater is not blowing hot air, but cold air instead, it is a hardware failure. Somewhere in the electronics, something went wrong.

Going through the different sections above hopefully helped you troubleshoot your space heater.

If you are good at electronics, you can try most fixes yourself. However, if you are an amateur or not knowledgeable at all, usually the best way to fix your space heater is by simply replacing it.

This is especially true if you don’t enjoy DIY electronics. Save yourself the hassle and get rid of your broken space heater.

By the way: I wrote an article about discarding old space heaters. Here’s how to trash a space heater (click here to see the article).

About the Author

Daniel Hirsch

Daniel is an electrical engineer, blogger, and author. He studied electrical engineering and information technology and decided to blog about heaters after working in the temperature sensing industry.