Does anyone have any information on this? I remember when I were a lad
those calor gas fires on wheels were all the rage with students during
the winter. But are they much cheaper to run nowadays than an electric
convector heater?

(I'm aware of the issues of condensation and the need for ventilation.
In fact looking back at some helpful chemical equations in the
archives here, burning 1kg of gas produces about 1.5l of water. At
that rate you'd really need to have the thing pumping out heat before
the walls start dripping.)

On Sun, 17 Oct 2010 05:55:23 -0700, Martin Pentreath wrote:

Does anyone have any information on this? I remember when I were a lad
those calor gas fires on wheels were all the rage with students during
the winter. But are they much cheaper to run nowadays than an electric
convector heater?

(I'm aware of the issues of condensation and the need for ventilation.
In fact looking back at some helpful chemical equations in the
archives here, burning 1kg of gas produces about 1.5l of water. At
that rate you'd really need to have the thing pumping out heat before
the walls start dripping.)

The increase in humidity caused by burning gas is likely to make it feel
sweltering when an LPG heater is on but cold as soon as you turn it off
again. If the heater is being used in ratty bottom-end-of-the-market
accommodation which is likely to tend to damp anyway then an LPG heater
will exacerbate the problem. For not much more than the cost of an LPG
heater one could buy a dehumidifier which, by reducing the humidity, will
make the place more comfortable at lower temperatures anyway, plus it'll
chuck out about 250Watts (for a compressor type) which may be enough to
keep the place warm much of the time anyway. Adding a cheap convector or
radiant halogen heater should then cope with colder spells. Capital cost
approx £100-120 for dehumidifier plus electric heater compared to c. £80
for LPG heater but should save on running costs fairly soon.

--
John Stumbles

Fundamentalist agnostic

Martin Pentreath wrote:

Does anyone have any information on this? I remember when I were a lad
those calor gas fires on wheels were all the rage with students during
the winter. But are they much cheaper to run nowadays than an electric
convector heater?

No, I don't think they are, though they may previously have been.

Portable room heaters would typically use 15 kg Calor bottles (blue,
hence butane). Wikipedia gives the heat of combustion of butane
as about 46 MJ/kg. 46 MJ corresponds to 12.8 kWh. This size of
Calor refill costs about £29 these days.

So the gas costs £1.93 per kg, and each kg gives the equivalent of
12.8 units of electricity, so the running cost is about 15 p/unit.

I pay less than that for my electricity, once I'm past the first
500 units per year which are more expensive, so I think electric
heaters (convectors or others) win hands down, especially as they
have no worries about condensation or carbon monoxide, and have a
lower capital cost.

On 17/10/2010 16:23, John Stumbles wrote:
On Sun, 17 Oct 2010 05:55:23 -0700, Martin Pentreath wrote:

Does anyone have any information on this? I remember when I were a lad
those calor gas fires on wheels were all the rage with students during
the winter. But are they much cheaper to run nowadays than an electric
convector heater?

(I'm aware of the issues of condensation and the need for ventilation.
In fact looking back at some helpful chemical equations in the
archives here, burning 1kg of gas produces about 1.5l of water. At
that rate you'd really need to have the thing pumping out heat before
the walls start dripping.)

The increase in humidity caused by burning gas is likely to make it feel
sweltering when an LPG heater is on but cold as soon as you turn it off
again. If the heater is being used in ratty bottom-end-of-the-market
accommodation which is likely to tend to damp anyway then an LPG heater
will exacerbate the problem. For not much more than the cost of an LPG
heater one could buy a dehumidifier which, by reducing the humidity, will
make the place more comfortable at lower temperatures anyway, plus it'll
chuck out about 250Watts (for a compressor type) which may be enough to
keep the place warm much of the time anyway. Adding a cheap convector or
radiant halogen heater should then cope with colder spells. Capital cost
approx £100-120 for dehumidifier plus electric heater compared to c. £80
for LPG heater but should save on running costs fairly soon.


It occurs to me that dehumidifier (to take water vapour, and make some
heat) plus gas (to make some heat, and supply water vapour) might work
quite well together.

But I'm scared of open fires in enclosed spaces. If _my_ boiler throws
a wobbly it'll poison next doors cat that's sitting on the fence. An
internal fire might poison me!

Andy

On 17 Oct, 13:55, Martin Pentreath
wrote:
Does anyone have any information on this? I remember when I were a lad
those calor gas fires on wheels were all the rage with students during
the winter. But are they much cheaper to run nowadays than an electric
convector heater?

(I'm aware of the issues of condensation and the need for ventilation.
In fact looking back at some helpful chemical equations in the
archives here, burning 1kg of gas produces about 1.5l of water. At
that rate you'd really need to have the thing pumping out heat before
the walls start dripping.)

Another issue I discovered was with the cylinders. They won't give
you your deposit back when you bring a cylinder in. They only do
exchanges.
They are a dangerous fire hazard in my view, inconvenient and
expensive to run.

A good one is about £80, plus cylinder, plus gas which is quite a
considerable cost. In reality you would most likely want two cylinders
re backup if one runs out during a snowed-up spell like 2009 so you
can choose when to go out rather than the heater.

A (very) powerful dessicant dehumidifier draws 390W (after the first
12hrs of not being used for some time), which is actually usable
heating and very good for drying. Example: PREM-I-AIR PRDHZ8 on Ebay
120525881861 is about £119 delivered. It is actually well built, well
thought out, not flimsy, a great many independent reviews around the
net - and it is quieter than an x-dry on which it is I suspect
genetically linked. A dessicant unit produces a fair amount of usable
heating, but also works at low temperatures - that model is very good
(I have had 17 dehumidifiers over the years and that one is only just
below the Mitsubishi which is the only quality unit out there, the
rest are just crap).

A good industrial electric heater is the 2kW industrial fan heater at
about £38.50 on Ebay - they use MICS (oven) elements, similar to fan
oven motor & stainless impeller, and the thermostat actually does turn
the elements on & off works too unlike the cheap nasty consumer fan
heaters that crop up in winter. Actual power options are 650W 1300W
2000W (or thereabouts). There is a 3kW / 3.3kW version out there which
is bigger, but on a 13A plug I am happier to take 2kW thanks. Cheap
enough to buy two 2kW fan heaters, just run them off different sockets
rather than the same double socket.