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"Electric furnaces" and other odd American heaters #220873 07/02/20 03:15 AM
Joined: May 2015
Posts: 76
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LongRunner Offline OP
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Those arrangements amuse me so much (as an Australian) that I had to start a thread just about them, so here I go. I guess it's just yet another American dogma (the USA being the land of the gullible) that "any" central heating (let's just forget the ancient open wood fires, which are pretty much the most obsolete technology on Earth rolleyes) is superior to portable "space" heaters in each room (to say nothing of conduction heating devices such as electric blankets and pads), so here's what I think of them:

Electric furnaces
The foremost folly of the bunch, these are basically just an oversized central fan heater.
The amusing part (to me anyway) ain't that the name itself isn't an apt description of how they work; just that having a different name falsely implies some kind of fundamental difference from portable fan heaters. dunno

I have this on full power (2400W here, thermostat maxed-out for continuous operation) as I've typed this post, and according to my thermometer it warms the best part of my (admittedly small) house to a surprising degree (or several wink ). By the way, since Kambrook (unlike far too many other manufacturers) actually implement proper QA on even their budget-oriented appliances (although they've ultimately settled into more mid-priced brackets for many items), they've never had to recall a heater they've made (and little else for that matter, as you can see for yourself); take that, American brands!
That's not to say you can't buy utter junk here if you cheap out (or just choose a bad brand, so be careful what you buy if you go to Hardly Normal laugh ), of course.

Baseboard heaters
Essentially large convectors installed in place of the skirting boards.
The only remotely interesting thing about their construction (that I've seen) is the form of heating element used, a tubular type with lots of fins fitted around it to increase the surface area (reducing the temperature presented to foreign materials inside the heater); not that this couldn't be done in a portable unit if desired, of course.
(Indeed some "panel" heaters do use sorts of finned elements, albeit made from ceramic since that's long been an "advanced" marketing buzz-word. Not that I'd pay the crazy prices often asked for them; I had one pair of pretentious 1kW units which were even confusing to operate, and they still weren't even appreciably better-built than a basic-but-competent De'Longhi HCM2030 is for about $60 Australian. crazy)

Our portable convector heaters (the kind with generally-bare elements inside a vented box, as distinct from the finned oil-filled heaters) seem just as capable of the near-indefinite lifespan achieved by North American fixed baseboard heaters, provided the following conditions apply (beyond being competently built, obviously):
  • The top grille (together with the rest of the casing) is made of metal, and not plastic with a marginal temperature rating (as some manufacturers have regretted quite badly, e.g. Goldair on their Turbo-Convectors of the 1990s).
  • They are protected by just a resettable bimetallic switch (or two in series if desired for redundancy), not the common one-shot thermal fuses (Microtemp and equivalents) with their aging problem (especially if marginally set).
  • They are kept reasonably clean, to prevent dust from building out of control (the moisture held by it can rust steel end terminals of the heating elements; those are usually nickel-plated, but only thinly in most cases).
  • Their elements aren't distorted in such a way as to create glowing spots (when maintaining those heaters, I straighten such regions out if observed).


Why heating was centralized in the first place
In general, the main reasons for making home (or office etc.) heat central are:
  • Getting rid of combustion fumes easily (which electric heaters don't produce in the first place; not at their point-of-use, anyway)
  • Saving costs on control and protection hardware (of which electric resistance heaters need very little to begin with, of course)
  • Some things (including PSUs by the way) work more efficiently when scaled up -- but not electric resistance heaters wink

So to implement central air heating using an electric resistance heater, completely misses the point (and indeed merely brings in the inevitable heat losses through the insulation, however good, of air ducting or water piping).
(The closest that any sensible arrangement gets is night-storage heaters which share a common timer; but the heaters themselves are still physically separate per-room.)

How central heating itself could be improved...
Observing just how good a well-designed fan heater is at distributing heat through the room it's in (I'd dare say Kambrook's current models are almost as good there as a Vornado would be), has made me ponder the prospects of fan-assisted heat exchangers (I won't take "radiator" as a synonym for those, since that's just so totally inaccurate) for central heat systems; basically they'd resemble water-cooling rigs for bleeding-edge computers, but maybe bigger (at least in the larger rooms). As a side benefit, the amount of heat delivered in each room could naturally be varied with the fan speed.

The flip-side of this, of course, afflicts air-conditioners used on their reverse cycle; since those (having been mounted high-up for their primary role of cooling) have to fight the natural order of air convection, hot and cold spots abound in practice (including my own home, and wherever else I've experienced them).
The same effect works against those wall-mounted fan heaters as commonly installed in UK (and to a lesser extent New Zealand) bathrooms; so I personally just use a portable fan heater in bathrooms with a 10A outlet, and a safe enough place to put the heater.

Of course, in a climate that's consistently cold (but not too cold for heat pumps to be effective) this problem could be avoided by mounting the indoor units at floor level; but Australia isn't like that. grin

Last edited by LongRunner; 07/02/20 03:25 AM.
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Re: "Electric furnaces" and other odd American heaters [Re: LongRunner] #220876 07/04/20 11:46 PM
Joined: Jul 2004
Posts: 9,514
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gfretwell Online Content
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Electric heat is probably most popular where people don't use it much or maybe where it is the only choice. Up north we had some kind of fossil fuel furnace, natural gas being the best if you could get it.
Down here in Florida they typically put 10-15KW heat strips (toaster wire) in the air handler for the A/C. Most people do not see the advantage in the complexity and extra cost of a heat pump. That may change now that more companies are abandoning the "cool only" systems. We haven't had the central heat on here in about 10 years. My wife has an "electric fireplace" that looks a whole lot like there is a fire going in there and it has a 1440w toaster wire heater in it. If she gets cold she turns that heater on. It warms up the living room.
That may be 10-15 mornings a year.


Greg Fretwell
Re: "Electric furnaces" and other odd American heaters [Re: gfretwell] #220878 07/05/20 12:21 AM
Joined: May 2015
Posts: 76
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LongRunner Offline OP
Member
Originally Posted by gfretwell
Electric heat is probably most popular where people don't use it much or maybe where it is the only choice.

I get that much, but I still suppose it'd be easier (in principle) to just install the necessary wiring and outlets for portable heaters of the required power. In my own home I basically have enough already, at least when the other short-duration heavy loads aren't on; out of interest I previously stepped up to using two 2400W fan heaters on separate circuits, which made the house warm enough that I actually had to take my shirt off. cool

And yes, heat pumps for heating only really work favorably in a rather narrow set of circumstances.
(Here's an interesting side-effect of heat distribution: When distributed evenly as I get with my fan heater, my body-temperature self-regulates much better so I sweat a lot less than when the heat is chaotically distributed, as I get from the air conditioners on reverse cycle. Which suggests that using the reverse-cycle could even end up as false economy in certain places; you may save a bit of electricity on the room heating itself, but those savings could easily be wiped-out by having to bath/shower more often. This is especially likely where the water heater itself uses a resistance element; my own is a combination solar-thermal unit with resistance booster.)

Last edited by LongRunner; 07/05/20 12:25 AM.
Re: "Electric furnaces" and other odd American heaters [Re: LongRunner] #220879 07/05/20 12:37 PM
Joined: Jul 2004
Posts: 9,514
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gfretwell Online Content
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The energy people here recommend that you keep your house at 68 (20c) in the winter so there is not a lot of sweating going on.


Greg Fretwell

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