Comments on: Another overpriced heater

by: Matt

Fri, 18 Jan 2008 00:01:00 +0000

Having grown up in Australia and having a reasonable understanding of physics I used to think that a watt of heat is just a watt of heat.

But then I read the “heating” chapter of a German book on house-building and there would appear to be quite a lot more to it. In particular, heating a room is not just about being warm - it’s about being comfortable.

Heating the air in a room (a la fan-heater) is fast because the air has little mass, but is relatively uncomfortable - the objects in the room take much longer to warm up, the air becomes dry, and opening a door or window will cool the room down very fast.
Radiated heat is supposed to be much better in this respect - the radiation passes more-or-less undisturbed through the air and heats the objects in the room, which will retain their heat much longer than air. The room can therefore be better ventilated (not so stuffy).

IOW, fan-heaters are not just crap because heating with electricity is expensive - they’re also producing crap heat.

by: bmorey

Thu, 17 Jan 2008 19:24:41 +0000

Everything old is new again? I saw a room heater based on large globes a few years ago. It was in a museum and dated from around 1908.

by: JoachimH

Tue, 08 Jan 2008 00:03:40 +0000

We were at the cool new house of a friend some years ago. Open plan architecture made the kitchen, living room AND three story stairwell with the furnished attic at the top one room. My only comment: “Man, you are going to have one cozy attic during winter”.

You can guess where he put his workplace and computer?

by: Daniel Rutter

Mon, 07 Jan 2008 13:22:37 +0000

Incidentally, the particular ceiling figure of 1500 watts for electric heaters in the USA comes from the fact that ordinary household circuits in the USA are rated for 15 amps, and there’s a section of the electrical code that forbids single appliances from consuming more than 80 per cent of the total rating for a circuit.

120 nominal volts times 15 amps times 0.8 equals 1440 watts; appliance manufacturers won’t push their luck any further than that nice round 1500.

by: Daniel Rutter

Mon, 07 Jan 2008 12:44:03 +0000

Here in Australia, the problem is of course usually cooling rather than heating. Australia has a rich crop of McMansions, some of which are fairly intelligently designed, but others of which have vast open-plan living areas with acres of awning-less windows.

It’s also fairly uncommon for Australian houses to have double glazing, serious insulation, or central heating. The paradoxical result of this is that although winter in the major Australian capitals is mild, many Australians actually spend more time being cold than many Finns.

by: Alan

Mon, 07 Jan 2008 12:04:53 +0000

Your discussion reminds me of a pet peeve when it comes to modern architecture: the “open plan” design. Kitchen dining, and even lounge areas have no boundary walls or doors. Sure, it looks pretty- but when winter comes there’s no way to heat “just one” room.