Engine Heaters

[Max Clark]

I've been looking into options for pre-heating my engine. Ideally something that can be triggered remotely before I leave my house.

I found the Aerotherm Heaters and different options to remotely turn on/off an electrical outlet.

What do you do? What should I look out for?

Thanks!

(p.s. this was inspired from a post on the Facebook Mooney Pilots group "What do you all use to preheat your engines?", Brad if you're on here I'd love to hear more about what you're doing)

 

[Fritz1]

Reiff makes good heater install kits, there are many options to turn an outlet on remotely, easy when there is wifi in the hangar, other option is mobile phone service which requires a small subscription, I live 10 min from airport and drive there the night before, reiff turbo xp on the engine and alien heater in cabin

[Fly Boomer]

5 hours ago, Max Clark said:

What do you do?

@OSUAV8TER sells a very popular switch that is controlled by cell phone.

[Ragsf15e]

I live in Washington, so preheat like 10 months of the year.

The switcheon and a reiff/tanis on the airplane are your “gucci” options.  I decided I could be a CB here (while still getting excellent preheat).  I bought a cheap ceramic heater, used some foil tape, hvac vent, and dryer vent to give it a flexible duct, and shove that into the cowl flap.  With the heater on low, I get nice warm air in the whole engine compartment.  Takes an hour or two to make sure it’s all evenly heated, but I like it.  My new plane came with a tanis so i just use that now.

As far as triggering it… I bought a used Verizon 4g lte hotspot off amazon for $25.  I got a iot sim chip from 1nce for $15.  Boom, i have a (very limited data) wifi connection in the hangar with no subscription!  Then I purchased a wifi outlet (i use ge cync) and I m in business!  Switcheon is probably the easy button, however, I am proud of my solution!

[Max Clark]

1 hour ago, Fritz1 said:

reiff turbo xp

Very cool setup.

[Max Clark]

46 minutes ago, Ragsf15e said:

I bought a cheap ceramic heater, used some foil tape, hvac vent, and dryer vent to give it a flexible duct, and shove that into the cowl flap.

I have something similar the previous owner made. Kinda worries me that it will catch on fire though.

[Ragsf15e]

30 minutes ago, Max Clark said:

I have something similar the previous owner made. Kinda worries me that it will catch on fire though.

I don’t think id set it up in a puddle of 100ll, but mine is all metal vents and i used it set to low.  Air was ~90.

[GeeBee]

Aerotherm is the bomb.

[Max Clark]

1 hour ago, GeeBee said:

Aerotherm is the bomb.

It seems like the cheap one might be the best?

[Ragsf15e]

One thing about aerotherm or other heaters promising a “30 minute” preheat… I have zero data to back this up, but I suspect the inside of the engine is still really cold.  That’s a lot of thermal mass to heat in 30 minutes.  You want the oil warm for sure, and the pistons, cylinders, etc at an acceptable temperature, not just the outside surfaces.  I prefer gentle heat for longer.  If you’re “preheating” in South georgia, 30 minutes is probably fine.

 

 

[GeeBee]

1 hour ago, Max Clark said:

It seems like the cheap one might be the best?

Yes, I have the Deuce. Owned it for 13 years. Not a lick of trouble and I run it continuously in the winter.

[Will.iam]

Milk carton heater $22 (even comes with overheat and tip over protection) on amazon. Aluminum hvac conduit and 4ft of dryer vent hose $25 and old used horse blanket for a total of less that $50 to preheat your airplane engine compartment for the ultimate CB club. 

[MikeOH]

5 minutes ago, Will.iam said:

old used horse blanket

Hmm, that smells like I would spring for a NEW horse blanket

[tcmb371]

In between flights when airplane is resting in hanger, I keep a Twin Hornet plugged in underneath the cowl, cowl plugs inserted, a thick blanket draped over the cowl and spinner, and cowl flaps shut. When i pull the plane out of the hangar i usually see CHT's around 65-70 degrees on the engine monitor.

https://www.aircraftspruce.com/catalog/eppages/aircraftheaters_08-12217.php 

[wombat]

If you have regular power and internet it's really easy.

My Mooney has a permanently installed pre-heat system that runs on 110V.  For the 182 though I just have a cheap ceramic space heater and some aluminum flexible ducting that I shove up into the cowl. And I drape a blanket over the cowl and tuck it in/around the air inlets

For both I control them with a Switchbot Plug Mini:  https://us.switch-bot.com/collections/plugs

It's a separate app on my phone which is annoying, but it does report the amperage draw, so I have confidence that it's actually turning on and off. 

I've noticed that when I try to use the feature of the app to schedule it to turn on, while it does turn on, 'disabling' or 'pausing' the schedule will not always work.   I check back a couple of days later and sometimes it will have turned on at the scheduled time (usually 3:30 AM) even though the schedule was disabled.

 

You do need internet there for it to work remotely and you need 110VAC for the heaters.  It's possible to do battery powered and cell-signal based stuff as well, but those are not necessary if you've got internet and regular electrical.

[Max Clark]

9 hours ago, tcmb371 said:

In between flights when airplane is resting in hanger, I keep a Twin Hornet plugged in underneath the cowl, cowl plugs inserted, a thick blanket draped over the cowl and spinner, and cowl flaps shut. When i pull the plane out of the hangar i usually see CHT's around 65-70 degrees on the engine monitor.

https://www.aircraftspruce.com/catalog/eppages/aircraftheaters_08-12217.php 

Wait so no ducts or hoses?

[Robm]

Im on a ramp (sadness) so I can't heat in a hanger and have mixed access to power.  I use a diesel heater and a cowl blanket.  I cover the cowl and duct the heat into the bottom of the cowl and then go get coffee for a couple hrs.  It does a decent job if not too horribly cold.

[Fly Boomer]

15 hours ago, Ragsf15e said:

I prefer gentle heat for longer.

Agree.

[Lax291]

3 minutes ago, Fly Boomer said:

Through the air inlets, dipstick door, or cowl flap?  I don't think I have 2 inches of clearance through any of those.

I've just started using the Hornet after using the electric heater with duct into the cowl flaps. 

I've used the hornet a few times, but much more convenient than what I was using before. Slips in through the air inlet (alternator belt side for my J) and sits right on top of the cylinder. Close up cowl flaps, insert plugs, and drape with a moving blanket.  If I know I'm flying the next day, I'll turn it on the day before.  If I don't fly, then it's still safe to keep it on as long as you want. You can also set the hornet on the cylinder right after shutdown, so no waiting for it to cool off. 

Now I use the old heater to preheat the cabin. 

[Fly Boomer]

2 minutes ago, Lax291 said:

I've just started using the Hornet after using the electric heater with duct into the cowl flaps. 

I've used the hornet a few times, but much more convenient than what I was using before. Slips in through the air inlet (alternator belt side for my J) and sits right on top of the cylinder. Close up cowl flaps, insert plugs, and drape with a moving blanket.  If I know I'm flying the next day, I'll turn it on the day before.  If I don't fly, then it's still safe to keep it on as long as you want. You can also set the hornet on the cylinder right after shutdown, so no waiting for it to cool off. 

Now I use the old heater to preheat the cabin. 

I have a 6-cylinder Continental.  I'll take a closer look next time I get to the hangar but, from memory, I don't think it would work on mine.

[Fritz1]

standard outlets have about 1600W, almost any heater will bring the engine to a decent startup temp over night with a blanket over the cowl, when time is an issue the installed heaters like Reiff and Tanis do better since they get the electric energy directly into the metal, 6 cyl engine is about 500 lb of steel and aluminum, takes so many kWh to heat that up, propane heaters need to be handled with care, takes longer than you think to heat an engine so it can be started without excessive wear, have seen guys that were in a hurry damage their composite cowl

[Pinecone]

My plane came with an oil sump heater.  I got one of the afore mentioned Switcheon remote switches, even though I live less than 10 minutes from my hanger.

When it is really cold. I put in the cowl plugs and have a Mac's insulated cowl cover.  I toss it over, but don't strap it one.  I put a BT thermometer in the oil door and typically see 80 degrees after over night.  This has worked very well down to 5F

 

[BDPetersen]

HD sells “smart switches/outlets” if you have wi-fi available. Otherwise the Switcheon does fine. (I have one to sell, BTW).

[Jackk]

On 12/10/2025 at 5:00 PM, Ragsf15e said:

I live in Washington, so preheat like 10 months of the year.

The switcheon and a reiff/tanis on the airplane are your “gucci” options.  I decided I could be a CB here (while still getting excellent preheat).  I bought a cheap ceramic heater, used some foil tape, hvac vent, and dryer vent to give it a flexible duct, and shove that into the cowl flap.  With the heater on low, I get nice warm air in the whole engine compartment.  Takes an hour or two to make sure it’s all evenly heated, but I like it.  My new plane came with a tanis so i just use that now.

As far as triggering it… I bought a used Verizon 4g lte hotspot off amazon for $25.  I got a iot sim chip from 1nce for $15.  Boom, i have a (very limited data) wifi connection in the hangar with no subscription!  Then I purchased a wifi outlet (i use ge cync) and I m in business!  Switcheon is probably the easy button, however, I am proud of my solution!

 What temps are you preheating in? 

[Ragsf15e]

10 minutes ago, Jackk said:

 What temps are you preheating in? 

Basically whenever it was 30s or cooler at night.  Obviously that’s a little above where you have to, but it’s nice to have everything around 80 to start.  I’ve gone a few times when it was single digits for a high and negative the night before.  Even the space heater/dryer vent shoved in the cowl flap worked well after several hours.