Why liquid-based heat instead of electric heat?

[bull]

I've wondered about this for years. Why did car makers ever start using heater cores to heat cars? And why do they continue to use it when electric heat would be so much more efficient and less problematic? Electric heat is instant (no waiting for the car to heat up), could be zonal, no issues with leaks or clogs in the heating system, easier and faster to repair and maintain, engine coolant would be better sealed with less potential for boiling issues, no more coolant smells inside or film on the windshield, etc. Talk to me. Convince me that electric heaters would not be a better way to go.

Those old, useless VW Beetles would have actually had a warm, dry heat inside with electric heat instead of the half-assed manifold system that incorporates exhaust fumes. No more heater core hoses bursting on top of your feet (happened to my brother), less coolant in the system, the list goes on...

[71charger_fan]

I would guess a combination of fire risk and inadequate electrical systems. Plus, once the coolant is warmed, it retains heat for a while. Electric heating elements cool off almost immediately.

[elacruze]

Strictly cost.

Mercedes-Benz had electric heaters in WWII, probably before that.

[Nacho-RT74]

on fluid heaters you are using an already done heat source by default what is already there even if you don't have heater, not extra energy needed to make it

[elacruze]

on fluid heaters you are using an already done heat source by default what is already there even if you don't have heater, not extra energy needed to make it

Exactly, coolant heat is nearly free to recover.

[ITSA426]

I remember the old VW bugs with combustion heaters behind the rear seat.  Back in the 70s a, co-worker arrived at the hangar on a cold winter morning with his headliner on fire from it.  We got the fire out, fixed the heater, and he drove it for the rest of the winter.  If you didn't have that, you had to carry a scraper to keep the windshield clear of frost from inside the car.  I believe the heater was a Stewart Warner with most of the same parts we had on hand for the airplanes.  At least there were some interchangeable parts.

Their manifold heat was about useless in Minnesota after October 1.  I think the problem with in-car electrical heat was adequate power source.  Plus using the warm engine coolant seems like a convenient, practical source, especially when copper was relatively inexpensive.

[Troy]

My 1984 Suburban had electric heat for the rear passengers. It was bulky and probably sucked up a lot of energy but it never worked while I had it. Reusing the engine heat is much more efficient than adding yet another drain to the electrical system (which also effects engine power and gas mileage). Modern cars heat up pretty darn fast any way. My 76 Power Wagon will almost be warm by the time I drive the 24 miles to work in 20 degree weather but my 2010 Kia will generally be warm enough to crank the heat by the time I make it to the first stop light (approx. 3 miles).

Troy

[68 RT]

VW's needed electric heat because they have air cooled engines.

[ITSA426]

But I never heard of them having it. 

Most single engine light airplanes get their cabin heat from a shroud around the muffler or exhaust manifolds.  They always seemed warm enough despite having air cooled engines.

[Troy]

But I never heard of them having it. 

Most single engine light airplanes get their cabin heat from a shroud around the muffler or exhaust manifolds.  They always seemed warm enough despite having air cooled engines.

That depends on the temperature! We flew a Bonanza and a Piper Aztec to Alabama from Ohio once in the middle of winter and only the pilot(s) and copilot(s) were warm enough to remove their coats and gloves. Another group was in a Citation and none of them had frostbite.

Troy

[bull]

I wonder about the longevity of fluid heat systems too. They work great in newer cars for sure but once the system gets a little older you lose a lot of efficiency and run into a lot of maintenance issues. Plus they virtually build new cars around the heater core and typically incorporate the evap core in the box so changing that out is almost always a major, costly PITA. I'm not saying car makers wouldn't make electric heat a pain in the butt to replace and maintain too but they could potentially be much simpler with plug and play modules.

Not sure I agree with electric heat being a drain on the system considering how much electrical junk they have on cars these days. Power everything is they way they build them now.

[resq302]

I could be wrong but I heard that newer Fords like my old 2005 F150 had electric heat till the engine got up to temp.  I know after driving about a block, I had some heat (it wasn't as hot as when the engine was up to norm. operating temp) but it was definitely warmer than when the engine actually started getting up to temp.

[b5blue]

My 52 Willys had a propane heater. The "Southwind" had a tank under the hood. Using it for me was out of the question but I was told by the guy I bought it from it worked very well. The amperage to run an electric heater is so much of a draw it would require a very large alternator and cost way too much to be practical.   

[bull]

The amperage to run an electric heater is so much of a draw it would require a very large alternator and cost way too much to be practical.    

I know those portable 12v heaters (with fan) usually only draw like 5-15 amps.

[Nacho-RT74]

make heat is the mayor power consumption everywhere... home, auto, etc...

[b5blue]

I looked into this last year wanting to put a rear defogger in my car. A decent watt heater pulled 25 amps and putting it in the rear made a long run of fairly large wire. In turn that would call for control relays to handle the load. Check eBay for "auto heaters" and you'll see whats out there.

[Purple68]

The amperage to run an electric heater is so much of a draw it would require a very large alternator and cost way too much to be practical.    

I know those portable 12v heaters (with fan) usually only draw like 5-15 amps.

A 12 volt heater that draws 15 amps will only give you 180 watts. To get enough heat from a 12 volt heater the amps would be really high. Not practical IMO.

[Cooter]

I can see Soccer mom's Kids #1 shoving something down the defroster vents now and catching on fire with a high enough powered Electric heat grid...

Plus, a heater is nothing but a controlled electrical short to ground...Sure, heater would work and you'd be replacing $600.00 alternators...

[ITSA426]

But I never heard of them having it. 

Most single engine light airplanes get their cabin heat from a shroud around the muffler or exhaust manifolds.  They always seemed warm enough despite having air cooled engines.

That depends on the temperature! We flew a Bonanza and a Piper Aztec to Alabama from Ohio once in the middle of winter and only the pilot(s) and copilot(s) were warm enough to remove their coats and gloves. Another group was in a Citation and none of them had frostbite.

Troy

I've flown a Bonanza when it was in the minus 20F range.  It was cold enough for the oil in the prop to make it sluggish, but the cabin heat was adequate. I haven't seen an Aztec that didn't have a combustion heater in the nose but I haven't seen them all.  Our twin Comanche's combustion heater was poor in flight until we removed the bird's nest from its fresh air intake.  I believe the Citation uses bleed air for heat and that offers a whole lot more heat but I've been in UH-1s on a cold Minnesota day and they seem barely adequate with their big, uninsulated interiors. 

Still, all more practical than electric heat and some days are just too cold for some equipment.

[bull]

Ok, I guess I'm convinced (mostly).

[Iceyone]

Lots of new cars these days have electric ass heaters. Heat generated in the cooling system is just waste heat so why not use it. My 30 Chevy has an aftermarket fluid heater. Haven't figured out exactly how old the heater really is.

[A383Wing]

Ok, I guess I'm convinced (mostly).

you sure??

[Mike DC]

                     
They say an internal combustion engine produces more heat than actual compression power by a wide margin.  Most of the energy in the gasoline gets spent producing heat and then wasted as the radiator cools it back off.  The amount of heat it takes to heat up the cabin would be a significant hurdle if it wasn't coming from a "free" source like the coolant.

[redmist]

The new dodge trucks have heater grids in them for cabin heat during warm up. That would be nice!

[six-tee-nine]

Dont forget that 50 years ago alot of cars ran on 6 volt power instead of the 12 volt we use now. The alternator did not find his way into the car yet instead they used DC generators wich did not provide the current like nowadays.
So what els was there available? Right hot water like radiators in our houses so the idea is as simple as it can get.....

I remember that my 6 volt '64 beetle almost every time stalled on me when i put the lights on when idling with a cold engine because of a weak spark........ I had to keep my foot on the throttle to keep her running until the engine warmed up a bit then it went ok but still if you stopped at a red light the lights already started dimming after a coulpe of seconds, so poor was the power supply in these days.....
I cant imagine pulling another 20 amps trough the circuit for an electric heater