I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far is
a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.

On 09/09/2010 in message Nick wrote:

I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far
is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.

A 20 Watt light bulb?

--
Jeff Gaines Dorset UK
By the time you can make ends meet they move the ends

"Nick" wrote in message
...
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far
is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.

http://uk.farnell.com/jsp/displayProduct.jsp?sku=3183166&CMP=e-2072-00001000

Any use?

--
Adam

"Jeff Gaines" wrote in message
...
On 09/09/2010 in message Nick wrote:

I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far
is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.

A 20 Watt light bulb?

Yeah - I was going to say that. Was going to suggest something like a yogurt
maker, but I think they do pretty much use a 20W lightbulb.

On 09/09/2010 15:14, Nick wrote:
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far is
a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.



Look for a "terrarium heater" in eBay or in a pet shop. Used by
reptile fanciers to keep their lizards and snakes warm. Basically a
simple heated mat.

You can probably get one with an internal stat but I'm not sure they'll
adjust temp downwards as far as you would like.

D

On 09/09/2010 15:42, Vortex7 wrote:
On 09/09/2010 15:14, Nick wrote:
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled
by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so
far is
a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.



Look for a "terrarium heater" in eBay or in a pet shop. Used by reptile
fanciers to keep their lizards and snakes warm. Basically a simple
heated mat.

You can probably get one with an internal stat but I'm not sure they'll
adjust temp downwards as far as you would like.

D


Also search "vivarium heater". Same meat, different gravy.

"Nick" wrote in message
...
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far
is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.



A small light bulb wired with an old c.heating roomstat.


mark

"John Whitworth" wrote in message
...


"Jeff Gaines" wrote in message
...
On 09/09/2010 in message Nick wrote:

I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by
a suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far
is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.

A 20 Watt light bulb?

Yeah - I was going to say that. Was going to suggest something like a
yogurt maker, but I think they do pretty much use a 20W lightbulb.
Thanks. I had meant to say in op that I have considered using a light bulb,
which would do the job and is the cheapest method. I would prefer the box
was was not illuminated (even though it would not be visible externally) but
I could mount a bulb within a 'tin can' arrangement. Biggest concern with
using a bulb is reliability.
I will give this a try and see how it goes. It'll only cost a bit of time as
I have all the bits required to hand.

On Thu, 09 Sep 2010 15:21:29 +0100, John Rumm wrote:

On 09/09/2010 15:14, Nick wrote:
I need to prevent a small outdoor enclosure from freezing. The box is
about 1m cube, constructed of wood, waterproof, well insulated and
fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled
by a suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so
far is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

Light bulb

I agree, but he'll have Hansen complaining that some of the energy is
wasted as light!

--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

"ARWadsworth" wrote in message
...

"Nick" wrote in message
...
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by
a suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far
is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.

http://uk.farnell.com/jsp/displayProduct.jsp?sku=3183166&CMP=e-2072-00001000

Any use?

--
Adam

Thanks Adam,
looks very useful and I'll keep it on record.
For now I'm going to try a lightbulb and see how it goes through the winter.

Nick wrote:
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far is
a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.



Buy three 7W 1kOhm resistors and connect them in series across the mains.

e.g. Rapid 62-8268

3 x 1000 = 3000 Ohm

P=v^2 /R = (240 x 240)/3000 = 19.2W

or do the same with 25W resistors, e.g. Rapid 62-8128 if you don't want
to run the 7W resistors quite so close to their limit.

On 9 Sep 2010 14:54:59 GMT, Bob Eager wrote:

On Thu, 09 Sep 2010 15:21:29 +0100, John Rumm wrote:

On 09/09/2010 15:14, Nick wrote:
I need to prevent a small outdoor enclosure from freezing. The box is
about 1m cube, constructed of wood, waterproof, well insulated and
fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled
by a suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so
far is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

Light bulb

I agree, but he'll have Hansen complaining that some of the energy is
wasted as light!

You'd need to work this out, but for my Father's seed-growing thingy I used
2 bulbs in series; if you want small, golfball lamps might do.
More of of the output is heat (the filaments just glow) and also they don't
blow every few weeks. I used a room 'stat as well - that was set by trial
and error as it was in the compartment with the bulbs, not in with the
plants.
--
Peter.
The gods will stay away
whilst religions hold sway

Nick wrote:

but
I could mount a bulb within a 'tin can' arrangement. Biggest concern with
using a bulb is reliability.

Putting a bulb inside a tin leads to very short bulb life. I tried this
last year for a bird egg incubator. It is incredible how hot the tin
gets, and how fast the bulb burns out. One bulb lasted less then 4
hours, a couple of others lasted less than a day.
I then tried the small candle type bulbs. These were slightly better,
though they still popped with alarming frequency, in the end I ended up
with a grapefruit tin, a normal bulb only half in the tin, to dissipate
some of its heat. This lasted for the few days I needed it, but the
downside was the constant light, which I didnt really want.
Alan.
--
To reply by e-mail, change the ' + ' to 'plus'.

On 9 Sep,
"Nick" wrote:

I need to prevent a small outdoor enclosure from freezing. The box is about
1m cube, constructed of wood, waterproof, well insulated and fairly
draught free. It does not need to be warm or hot, just a few degrees above
freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat. I reckon about 20W would do the job but
the smallest I have found so far is a 12inch tubular heater @ 45W. This
would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

This is a very good use for incandescent lamps. Wire two 60w in series, then
they are seriously under-run and last forever. That should give you about
20w. Adjust lamp size if power is too high/low.

--
B Thumbs
Change lycos to yahoo to reply

On 9 Sep,
"Nick" wrote:

Biggest concern with using a bulb is reliability.

Two in series (seriously under-run) are very reliable.

--
B Thumbs
Change lycos to yahoo to reply

On Thu, 9 Sep 2010 15:14:17 +0100, "Nick"
wrote:

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far is
a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

Soil heating cable? 4m is about 25W.

Electric animal heating pad - about 12W
http://www.hygienesuppliesdirect.com...cts/prod110283

mirror demister pads - 7/15/25W
http://www.mirrordemisters.co.uk/

or

http://cgi.ebay.co.uk/Mirror-Demiste...em2e a380eadb

On 9 Sep, 15:14, "Nick" wrote:
I need to prevent a small outdoor enclosure from freezing.

Best thing is real anti-freeze tape. It does your control problem for
you.

Otherwise (like the anti-condenstation heater in my chisel cupboard),
a big wirewound resistor.

On 9 Sep, 15:52, "Nick" wrote:
"John Whitworth" wrote in message

...





"Jeff Gaines" wrote in message
...
On 09/09/2010 in message Nick wrote:

I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by
a suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far
is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.

A 20 Watt light bulb?

Yeah - I was going to say that. Was going to suggest something like a
yogurt maker, but I think they do pretty much use a 20W lightbulb.

Thanks. I had meant to say in op that I have considered using a light bulb,
which would do the job and is the cheapest method. I would prefer the box
was was not illuminated (even though it would not be visible externally) but
I could mount a bulb within a 'tin can' arrangement. Biggest concern with
using a bulb is reliability.
I will give this a try and see how it goes. It'll only cost a bit of time as
I have all the bits required to hand.- Hide quoted text -

- Show quoted text -

Use two 15w bulbs. Or even a CFL.

On 9 Sep, 19:39, Andy Dingley wrote:
On 9 Sep, 15:14, "Nick" wrote:

I need to prevent a small outdoor enclosure from freezing.

Best thing is real anti-freeze tape. It does your control problem for
you.

Otherwise (like the anti-condenstation heater in my chisel cupboard),
a big wirewound resistor.

whoa..... a *heated* chisel cupboard.....????

now ya jus biggin yoself up ..

Jim K

"Nick" wrote in message
...
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far
is a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.


I was going to suggest, as others have, that a wing mirror demister can be
had from any roadside. Then I thought where to get the 12V from - which
meant transformer... And of course, you only need the transformer: if your
box is insulated I expect even just leaving a phone charger or even laptop
transformer in it will keep it above freezing. Just add thermostat.

More elegantly I have what was I think sold as a drum warming tape for home
beer making. It is a 'silky snake' a metre long, presumably with electric
blanket element inside. I have had it hung in an insulated cupboard with a
20C thermostat on for many years - it keeps my wine demijohns bubbling.

And another alternative would be some of that underfloor heating matting,
which you can cut to size. It's in our new shower unit, which is not much
bigger than your box.

S

In message , Nick
writes
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far is
a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Thinking laterally

does it contain lettuce, tomatoes or ganga?

Is it hermetically sealed?

If not, why not get a rabbit and us the enclosure as a hutch

its body heat will keep the temperature above zero and, come the spring,
you will have a fine meal


--
geoff

On 9 Sep, 20:29, Jim K wrote:

Otherwise (like the anti-condenstation heater in my chisel cupboard),
a big wirewound resistor.

whoa..... a *heated* chisel cupboard.....????

Japanese chisels. You can pay serious money for good, wide ones. I
could also buy another Norris for the price of the iron from one of my
planes. It doubled in price overnight when the smith died. I keep that
one in the lounge!

On 10/09/2010 in message geoff wrote:

If not, why not get a rabbit and us the enclosure as a hutch

its body heat will keep the temperature above zero and, come the spring,
you will have a fine meal

But no lettuce left to go with it!

--
Jeff Gaines Dorset UK
The facts, although interesting, are irrelevant

On 10 Sep, 00:15, geoff wrote:
In message , Nick
writesI need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far is
a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Thinking laterally

does it contain lettuce, tomatoes or ganga?

Is it hermetically sealed?

If not, why not get a rabbit and us the enclosure as a hutch

its body heat will keep the temperature above zero and, come the spring,
you will have a fine meal

mmm shurely even an un-stoned hungry rabbit would *probably* manage to
scrat/eat its way out of a wooden box?

Jim K

On Sep 9, 5:01*pm, wrote:
On 9 Sep, *
* * *"Nick" wrote:

Biggest concern with *using a bulb is reliability.

Two in series (seriously under-run) are very reliable.

Yes, but still fragile, and still a single point of failure. You're
better off running 2 parallel circuits of underrun bulb or bulbs, such
that either one alone gives enough power.

The neater way to do this is with 2 lightbulbs, each supplied via a
1kV diode. A 1N4007 is rated at 1A, so will handle a lamp of apx 0.1A
= a 25w lamp max. I'd far rather use capacitors, more reliable,
greater max lamp power and adjustability. 2.2uF with a 40w bulb would
give you in the region of what you want.
http://wiki.diyfaq.org.uk/index.php?title=Droppers


NT

In article , Nick nick.swanston@NOSPAM
gmail.com writes
I need to prevent a small outdoor enclosure from freezing.
The box is about 1m cube, constructed of wood, waterproof, well insulated
and fairly draught free.
It does not need to be warm or hot, just a few degrees above freezing.

The heater needs to be mains voltage and small. It will be controlled by a
suitable froststat or thermostat.
I reckon about 20W would do the job but the smallest I have found so far is
a 12inch tubular heater @ 45W.
This would do the job but I would prefer something physically smaller.

Any ideas or alternative suggestions please?

TIA
Nick.


Last year B&Q were selling some low wattage (about 50 I think)
thermostatically controlled heaters for about £10 (IIRC)
--
John Alexander,

Remove NOSPAM if replying by e-mail