Cartridge heater in air

I have a 100W cartridge heater for heating the air in a cabinet. The heater is run by a phase control dimmer 120VAC. After looking around, this seemed to be the best solution (need 120VAC, resistive, about 100 watts)

My question is, should these types of heaters be applied in air?

I have read some forum threads where people do this. I would feel more comfortable having a finned heat sink to go around the cartridge heater, but am not finding any on the web. The heat sink would also provide some thermal mass.

I have successfully test run my project with the heater in air. The heater glows red (which others have observed), and I repositioned a fan to blow directly on the heater.

My concern is reliability.


My question is, should these types of heaters be applied in air?

No. They are designed to be placed in holes in thermally conductive mass, usually with thermally conductive paste.

Clearly it works in free air, but I think the long term reliabilty would be better if it were running as intended.

There is also the safety issue of having an exposed red hot heater. What happens if the fan stops?

What temperature are you trying to reach in the cabinet. How quickly?

How about a star heat sink and drill a 9.5 mm hole in it.

Given the cost though it may be cheaper to use a domestic tubular heater if you have the space.

Heating to 100F. I don't need any fast ramp.

Actually, I don't think the fan makes much difference.

The star heat sink might work, if i can drill the correct size hole.

I am seeing some star heaters for $10 to $20 on ebay.

tubular heaters seem more expensive. If not, please send some links.

Aquariums used to be heated with 100 light bulbs.
They may not take kindly to frequent switching but PWM might work.

The reason a 100W heater was chosen was because I used a 100W light bulb the last time I did this (about 30 years ago). But being a new age, a bulb was not up to the task. Today, only a microprocessor, dimmer, custom made circuit card, and clap trap would do.

On the bulb, I did not want the light, so thought a resistive element would be simple.

Possibly another option...

Ceramic bulb heaters -

Only reason I was aware of them cause I used to keep a snake. So I thought it might be something useful in your situation.

tubular heaters seem more expensive. If not, please send some links.

In the UK i see some at 25 or less.
Birddog idea seems to be a good one.
Halogen heaters can be had but are generaly more heat than you require.
I have used a halogen cooker as a SMT oven before but the tubes do not seem to last well for some reason.

I can collect loaclly but shipping costs would significantly increase the price.

The ceramic bulb heaters give radiant heat, which I want to avoid (same problem with a light bulb; I should have been more specific). I am shooting for convective heating to control the temperature to a specific range.

A 100w aluminium-cased resistor bolted with thermal paste to a piece of ally sheet might be a reasonable solution.


The ceramic bulb heaters give radiant heat,

So does a glowing red cartridge heater. Drill a hole in a star led heat sink.