I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Any thoughts, comments or suggestions welcome

On 27/02/2018 20:41, Enrie Membership wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Insulate the walls as best you can with polystyrene sheet. Try and avoid
drafts.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

That or a modest fan heater on its frost stat setting.

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Absolutely not unless you want everything to rust to blazes from the
resulting humidity. And if anything goes wrong get covered in soot -
very bad for greenhouse plants. Also you need ventilation as well to
sustain the flame.

Any thoughts, comments or suggestions welcome

Electric heating on a thermostat. You might want to monitor the dew
point rather than

--
Regards,
Martin Brown

On Tue, 27 Feb 2018 20:41:58 +0000, Enrie Membership
wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Any thoughts, comments or suggestions welcome

Do mean you one of those standalone heaters or a fixed one with a
flue?

Paraffin will produce water vapour , almost equivalent to the amount
of Paraffin used. Not ideal in the proximity of things that can rust
like old engines. A heater with a flue will help but some heat will go
up it as well so the electric may well be cheaper to run.

G H

On Tue, 27 Feb 2018 20:41:58 +0000, Enrie Membership wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Any thoughts, comments or suggestions welcome

If it is not in total shade during the day then a solar air heater and some
decent insulation in the structure like PIR foam (Kingsapn/Celotex etc)

http://www.reuk.co.uk/wordpress/sola...ar-air-heater/

--

On 27/02/18 20:41, Enrie Membership wrote:
I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Any thoughts, comments or suggestions welcome



Dessicant based dehumidifier - mine can run at 300W or 600W and it's a
double win - bit of warmth and the air is dried out.

If you have a fairly airtight shed it seems to work very well. My shed
has 50mm celotex on the floor and about 60% of the walls (rest and roof
is a later tuit) and 600W can bring the temperature up a good 10-15
degrees - but it doesn't need to run that hard to keep the humidity
below about 40-45%.

On 27/02/18 21:14, Martin Brown wrote:
On 27/02/2018 20:41, Enrie Membership wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter.
I do have an electrical supply nearby. What are folks thoughts on the
most efficient form of heating that will keep the shed just above
freezing point?.

Insulate the walls as best you can with polystyrene sheet. Try and avoid
drafts.

Electrical Tubular heater 5' 200w (has the advantage of having a
frostat onboard)

That or a modest fan heater on its frost stat setting.

I wouldn't - modern fan heaters can be a horrid fire risk - bit of fluff
builds up inside the front grille and you get a red-hot spot (I've seen it).

If you just want a pure heater, oil filled radiator is the safest bet,
or a dehumidifer.


Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Absolutely not unless you want everything to rust to blazes from the
resulting humidity. And if anything goes wrong get covered in soot -
very bad for greenhouse plants. Also you need ventilation as well to
sustain the flame.

Any thoughts, comments or suggestions welcome

Electric heating on a thermostat. You might want to monitor the dew
point rather than

On 27/02/18 21:32, The Other Mike wrote:
On Tue, 27 Feb 2018 20:41:58 +0000, Enrie Membership wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Any thoughts, comments or suggestions welcome

If it is not in total shade during the day then a solar air heater and some
decent insulation in the structure like PIR foam (Kingsapn/Celotex etc)

http://www.reuk.co.uk/wordpress/sola...ar-air-heater/


+1 to the celotex - reduces vapour transmission and gives a way/reason
to seal up the draughts with foam too

On Tue, 27 Feb 2018 20:41:58 +0000, Enrie Membership
wrote:


I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Dehumidifier suitable for low temperatures. Dries and heats air.

On 27/02/18 21:49, Tim Watts wrote:
On 27/02/18 21:14, Martin Brown wrote:
On 27/02/2018 20:41, Enrie Membership wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter.
I do have an electrical supply nearby. What are folks thoughts on the
most efficient form of heating that will keep the shed just above
freezing point?.

Insulate the walls as best you can with polystyrene sheet. Try and avoid
drafts.

Electrical Tubular heater 5' 200w (has the advantage of having a
frostat onboard)

That or a modest fan heater on its frost stat setting.

I wouldn't - modern fan heaters can be a horrid fire risk - bit of fluff
builds up inside the front grille and you get a red-hot spot (I've seen it).

Absolute nonsense. I've been using fan heaters in greenhouses for over
20 years. All sorts of crud on the elements - spiders' webs, dust, small
dead leaves, other plant-based material, etc, and I've never seen or
smelt evidence of burning. After about eight years, I did have one
element go o/c, though, and I've had a thermostat fail with crud on the
contact points. And I only use the absolutely cheapest 1 - 2kW fan heaters.

Anyway, if someone was really concerned about fire, they could always
use a ceramic-element fan heater.

--

Jeff

Yes, also insulate the floor and roof as a lot of the heat in my old now
defunct shed was lost through those means.
I am going to try to make something similar this year, but it looks like
I'll have to get somebody in, but the costs seem to go a bit mad if you want
anything other than a boring old shed these days.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Martin Brown" wrote in message
news
On 27/02/2018 20:41, Enrie Membership wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Insulate the walls as best you can with polystyrene sheet. Try and avoid
drafts.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

That or a modest fan heater on its frost stat setting.

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Absolutely not unless you want everything to rust to blazes from the
resulting humidity. And if anything goes wrong get covered in soot - very
bad for greenhouse plants. Also you need ventilation as well to sustain
the flame.

Any thoughts, comments or suggestions welcome

Electric heating on a thermostat. You might want to monitor the dew point
rather than

--
Regards,
Martin Brown

On Tuesday, 27 February 2018 20:42:02 UTC, Enrie Membership wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Any thoughts, comments or suggestions welcome


http://wiki.diyfaq.org.uk/index.php/Electric_heating
all electric heaters are 100% efficient.
Radiators are the lowest fire risk, low loading tubular heaters next. Bowl heaters the greatest.


NT

On 27/02/18 22:22, Jeff Layman wrote:

Absolute nonsense.

No it's not - and your experience is probably based on your heaters
being 20 years old.

I was running fan heaters in the early parts of my bungalow renovation
(10 years ago) and I bought "decent" ones. Except they were plastic. I
caught one with a red hot spot on the element and right in front of
that, the plastic grill was melting.

The others started doing that and I had to take them to bits to clean
the fluff out.

Mordern fan heaters IME are unsafe by design.

I've been using fan heaters in greenhouses for over
20 years. All sorts of crud on the elements - spiders' webs, dust, small
dead leaves, other plant-based material, etc, and I've never seen or
smelt evidence of burning. After about eight years, I did have one
element go o/c, though, and I've had a thermostat fail with crud on the
contact points. And I only use the absolutely cheapest 1 - 2kW fan heaters.

Anyway, if someone was really concerned about fire, they could always
use a ceramic-element fan heater.


Or an oil filled rad like I suggested - probably the safest of all
electric heaters.

On 28/02/18 07:31, Brian Gaff wrote:
Yes, also insulate the floor and roof as a lot of the heat in my old now
defunct shed was lost through those means.
I am going to try to make something similar this year, but it looks like
I'll have to get somebody in, but the costs seem to go a bit mad if you want
anything other than a boring old shed these days.
Brian


Because my shed is felted, I can't do the roof yet (or the wood will get
trapped between 2 impermeable layers).

I'm planning to strip the felt, celotex the top, batten a ventilation
space in, ply and finish with something nicer - some plastic tiles or
shingles.

The ply will let me extend the roof a foot all round to give water
shedding away from the wall too.

On 27/02/2018 22:22, Jeff Layman wrote:
On 27/02/18 21:49, Tim Watts wrote:
On 27/02/18 21:14, Martin Brown wrote:
On 27/02/2018 20:41, Enrie Membership wrote:

I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter.
I do have an electrical supply nearby. What are folks thoughts on the
most efficient form of heating that will keep the shed just above
freezing point?.

Insulate the walls as best you can with polystyrene sheet. Try and avoid
drafts.

Electrical Tubular heater 5' 200w (has the advantage of having a
frostat onboard)

That or a modest fan heater on its frost stat setting.

I wouldn't - modern fan heaters can be a horrid fire risk - bit of fluff
builds up inside the front grille and you get a red-hot spot (I've
seen it).

Absolute nonsense. I've been using fan heaters in greenhouses for over
20 years. All sorts of crud on the elements - spiders' webs, dust, small
dead leaves, other plant-based material, etc, and I've never seen or
smelt evidence of burning. After about eight years, I did have one
element go o/c, though, and I've had a thermostat fail with crud on the
contact points. And I only use the absolutely cheapest 1 - 2kW fan heaters.

Mine have always been fine in the greenhouse too.

Anyway, if someone was really concerned about fire, they could always
use a ceramic-element fan heater.

The other option are the rod type oil filled heaters. The main advantage
of a fan heater in a modest sized space is that it stirs the air around
so you don't get cold spots where condensation can occur.

--
Regards,
Martin Brown

In article ,
Tim Watts writes:
On 27/02/18 20:41, Enrie Membership wrote:
I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Electrical Tubular heater 5' 200w (has the advantage of having a frostat
onboard)

Old fashioned paraffin heater (I would have to light it if the
temperature was liable to drop below freezing)

Any thoughts, comments or suggestions welcome



Dessicant based dehumidifier - mine can run at 300W or 600W and it's a
double win - bit of warmth and the air is dried out.

Seen enough of those at Repair Cafes that I would never leave one
running unattended.

Number 1 failure mode is the dessicant disk jams so it's no longer
rotating, and the heater then heats one spot continuously, and it
burns it.

Also seen one where the mica element supports in the fan heater part
had fallen to pieces and the element wire coils had dropped out in
clump against the dessicant disk, burning it.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 27/02/2018 22:11, Peter Parry wrote:
On Tue, 27 Feb 2018 20:41:58 +0000, Enrie Membership
wrote:


I've just had a 6' x 6' shed erected in the garden to house a few
stationary engines which I want to keep above freezing in the winter. I
do have an electrical supply nearby. What are folks thoughts on the most
efficient form of heating that will keep the shed just above freezing
point?.

Dehumidifier suitable for low temperatures. Dries and heats air.


My Ebac homedry has a circuit board with a 555 timer.

Once per hour it operates a solenoid valve in the gas stream
reversing the flow of warm refridgerant through the cooling
coils, so the ice crackles, melts and falls off. It does this
for about 3 mins and then reverts to normal operation.

QED, should work at very low temperatures.

I bought it 2nd hand in 1988, it's been around the world, to
the pacific for 2 years, and back. Still going strong.

You can buy special heating cable that is mains rated.

On 28/02/18 23:30, Andrew Gabriel wrote:

Dessicant based dehumidifier - mine can run at 300W or 600W and it's a
double win - bit of warmth and the air is dried out.

Seen enough of those at Repair Cafes that I would never leave one
running unattended.

Number 1 failure mode is the dessicant disk jams so it's no longer
rotating, and the heater then heats one spot continuously, and it
burns it.

Also seen one where the mica element supports in the fan heater part
had fallen to pieces and the element wire coils had dropped out in
clump against the dessicant disk, burning it.


Thanks for that - I was a bit cautious about the heater in them as I
know it runs hot.

I rigged my shed unit so it's only allowed to run when someone is home
and "awake" (controlled through ZWave) (at home + awake is a notional
thing based on based times of day mostly)

How flammable is the desiccant disc, do you reckon?


Oh well - oil filled rad or intrinsically safe heater bar for the OP
then, unless he can run his at safe times.

On 01/03/18 11:19, Andrew wrote:

My Ebac homedry has a circuit board with a 555 timer.

Once per hour it operates a solenoid valve in the gas stream
reversing the flow of warm refridgerant through the cooling
coils, so the ice crackles, melts and falls off. It does this
for about 3 mins and then reverts to normal operation.

QED, should work at very low temperatures.

I bought it 2nd hand in 1988, it's been around the world, to
the pacific for 2 years, and back. Still going strong.

You can buy special heating cable that is mains rated.

I wonder if anyone still makes a unit like that?

I'd prefer the safety of a refrigerant unit (based on what Andrew said
earlier) but the purpose is to keep a shed dry so it will get cold.

Tim Watts Wrote in message:
On 01/03/18 11:19, Andrew wrote:

My Ebac homedry has a circuit board with a 555 timer.

Once per hour it operates a solenoid valve in the gas stream
reversing the flow of warm refridgerant through the cooling
coils, so the ice crackles, melts and falls off. It does this
for about 3 mins and then reverts to normal operation.

QED, should work at very low temperatures.

I bought it 2nd hand in 1988, it's been around the world, to
the pacific for 2 years, and back. Still going strong.

You can buy special heating cable that is mains rated.

I wonder if anyone still makes a unit like that?

I'd prefer the safety of a refrigerant unit (based on what Andrew said
earlier) but the purpose is to keep a shed dry so it will get cold.


Define "cold"...
At 0 / minus anything, there is relatively little water vapour in
the outdoor atmosphere, so your "shed based damp" should be
migrating happily outside by itself without the need of a
dehumidifier?
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 01/03/18 15:56, jim wrote:
Tim Watts Wrote in message:
On 01/03/18 11:19, Andrew wrote:

My Ebac homedry has a circuit board with a 555 timer.

Once per hour it operates a solenoid valve in the gas stream
reversing the flow of warm refridgerant through the cooling
coils, so the ice crackles, melts and falls off. It does this
for about 3 mins and then reverts to normal operation.

QED, should work at very low temperatures.

I bought it 2nd hand in 1988, it's been around the world, to
the pacific for 2 years, and back. Still going strong.

You can buy special heating cable that is mains rated.

I wonder if anyone still makes a unit like that?

I'd prefer the safety of a refrigerant unit (based on what Andrew said
earlier) but the purpose is to keep a shed dry so it will get cold.


Define "cold"...
At 0 / minus anything, there is relatively little water vapour in
the outdoor atmosphere, so your "shed based damp" should be
migrating happily outside by itself without the need of a
dehumidifier?



Defined as "works when it needs to work"

Yes, you're quite right - but interestingly my Meaco 20l compressor unit
goes down to 5C (just checked).

That can be slimly beaten by the

https://www.ebac.com/dehumidifiers/p...er-de8421gy-gb

(Ebac was mentioned earlier)

which goes down to 3C - which clearly would do the job as:

a) It doesn't get that cold often;

b) As you rightly say, damp is not a problem at =0C



As I drive mine through a ZWave switch, I can add temperature as a
factor into the switch on programming.

On 01/03/18 16:07, Tim Watts wrote:

That can be slimly beaten by the

slightly


https://www.ebac.com/dehumidifiers/p...er-de8421gy-gb


Having just looked, it's costing me £4/week to run the desiccant unit
which is worth it in terms of stopping stuff rusting - I've had no
problems with things stored there since I started doing this.

However, the Ebac takes about 1/2 the power, so in about 3 years it
would pay for itself. Desiccant unit is old too - might be time for an
upgrade...

Tim Watts Wrote in message:
On 01/03/18 16:07, Tim Watts wrote:

That can be slimly beaten by the

slightly


https://www.ebac.com/dehumidifiers/p...er-de8421gy-gb


Having just looked, it's costing me £4/week to run the desiccant unit
which is worth it in terms of stopping stuff rusting - I've had no
problems with things stored there since I started doing this.

However, the Ebac takes about 1/2 the power, so in about 3 years it
would pay for itself. Desiccant unit is old too - might be time for an
upgrade...


Istr the efficiency of compressor dehumidifiers is hampered below
15deg c? (hence the usual recommendation for using dessicant
types in colder areas).

That deficiency might knacker the sums on "paying for itself"?
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 01/03/18 16:45, jim wrote:
Tim Watts Wrote in message:
On 01/03/18 16:07, Tim Watts wrote:

That can be slimly beaten by the

slightly


https://www.ebac.com/dehumidifiers/p...er-de8421gy-gb


Having just looked, it's costing me £4/week to run the desiccant unit
which is worth it in terms of stopping stuff rusting - I've had no
problems with things stored there since I started doing this.

However, the Ebac takes about 1/2 the power, so in about 3 years it
would pay for itself. Desiccant unit is old too - might be time for an
upgrade...


Istr the efficiency of compressor dehumidifiers is hampered below
15deg c? (hence the usual recommendation for using dessicant
types in colder areas).

That deficiency might knacker the sums on "paying for itself"?


Possible - but I also value "not catching fire"

In article ,
Tim Watts writes:
On 28/02/18 23:30, Andrew Gabriel wrote:

Dessicant based dehumidifier - mine can run at 300W or 600W and it's a
double win - bit of warmth and the air is dried out.

Seen enough of those at Repair Cafes that I would never leave one
running unattended.

Number 1 failure mode is the dessicant disk jams so it's no longer
rotating, and the heater then heats one spot continuously, and it
burns it.

Also seen one where the mica element supports in the fan heater part
had fallen to pieces and the element wire coils had dropped out in
clump against the dessicant disk, burning it.


Thanks for that - I was a bit cautious about the heater in them as I
know it runs hot.

I rigged my shed unit so it's only allowed to run when someone is home
and "awake" (controlled through ZWave) (at home + awake is a notional
thing based on based times of day mostly)

How flammable is the desiccant disc, do you reckon?

I've no idea. It looks like a cardboard honeycomb, but I think it
must be more fire resistant than cardboard, although it did char.

Oh well - oil filled rad or intrinsically safe heater bar for the OP
then, unless he can run his at safe times.

The shed I did for someone uses an old oil filled radiator.
It's rated 1kW, but mostly it runs with a half-wave rectifying
diode to halve the power output.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Tim Watts Wrote in message:
On 01/03/18 16:45, jim wrote:
Tim Watts Wrote in message:
On 01/03/18 16:07, Tim Watts wrote:

That can be slimly beaten by the

slightly


https://www.ebac.com/dehumidifiers/p...er-de8421gy-gb


Having just looked, it's costing me £4/week to run the desiccant unit
which is worth it in terms of stopping stuff rusting - I've had no
problems with things stored there since I started doing this.

However, the Ebac takes about 1/2 the power, so in about 3 years it
would pay for itself. Desiccant unit is old too - might be time for an
upgrade...


Istr the efficiency of compressor dehumidifiers is hampered below
15deg c? (hence the usual recommendation for using dessicant
types in colder areas).

That deficiency might knacker the sums on "paying for itself"?


Possible - but I also value "not catching fire"


Absolutely - a nice dry shed will go up marginally quickerthan a
damp one :-)
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

In article ,
jim k writes:
Tim Watts Wrote in message:
On 01/03/18 11:19, Andrew wrote:

My Ebac homedry has a circuit board with a 555 timer.

Once per hour it operates a solenoid valve in the gas stream
reversing the flow of warm refridgerant through the cooling
coils, so the ice crackles, melts and falls off. It does this
for about 3 mins and then reverts to normal operation.

QED, should work at very low temperatures.

I bought it 2nd hand in 1988, it's been around the world, to
the pacific for 2 years, and back. Still going strong.

You can buy special heating cable that is mains rated.

When I wanted about 15m of it, easiest way was to use standard
1mm T&E, short the far end, and feed it with an electronic 12V
halogen transformer. I bought a 250W transformer and connected
it to the cable, using a mains power meter to make sure it was
within the load range (IIRC, I could make it 150W or 230W,
depending if I connected the earth or not). This solution was
orders of magnitude cheaper than mains heating wire. It's taped
to an underground water main which I could only get 500mm deep
rather than the recommened 750mm because the end connections
were nowhere near that deep (and the original lead pipe was only
a few inches deep at one end).

Note you cannot work out the power rating by measuring the
resistance of the wire and using ohms law. An electronic halogen
transformer will be at least 20kHz output, and the skin effect
comes into play, and the impedance will be significantly higher
than the DC resistance, which in this case is a big bonus.

I wonder if anyone still makes a unit like that?

I'd prefer the safety of a refrigerant unit (based on what Andrew said
earlier) but the purpose is to keep a shed dry so it will get cold.


Define "cold"...
At 0 / minus anything, there is relatively little water vapour in
the outdoor atmosphere, so your "shed based damp" should be
migrating happily outside by itself without the need of a
dehumidifier?

I've been controlling the humidity in a large shed for someone for
5 years now. Originally I was thinking I would need a dehumidifier,
but I didn't have a spare one so started with a heater. That works
so well, I stuck with it. It's an old oil-filled 1kW radiator,
running at half power with a half-wave rectifier.

You are right that the absolute humidity (dew point) is low at low
temperature even when the relative humidity is 100%. This means that
a very small temperature rise is required to drop the relative
humidity and protect against condensation.

However, without protection, that moisture is dumped out on the
contents of the shed when the temperature drops any further, and
that's exactly what you don't want.

I keep the relative humidity to no higher than 80%, and the contents
of the shed are on palets and spaced away from the walls so there's
circulation all around (otherwise you will get cold spots which drop
below the dew point). It also has frost protection which kicks in
at 5C (and bumps radiator up to 1kW at 3C, although I just searched
through the logs and that's never happened - coldest shed has ever
got is 4.5C when it was -4.9C outside on Tuesday).

I monitored the costs in the first year, and I think it was around
£50 for the electricity. Previously it was costing £200/month
to store the stuff in a warehouse, so that's an enormous saving.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]