is there such a thing as a battery powered heater so I can use it in my shed?
Are there heaters available for caravans that will run off their leisure batteries when they're staying off grid (aka not plugged into the mains at a camp site)? You'd need to put a bit of work into wiring up as it wouldn't be a direct attach to a battery but a trip to the local caravan sales place might be something to consider if no one else has any ideas.
I'd love someone to prove me wrong here, as it would be a great solution for me too, but when I looked into it last year I came to the conclusion it would be immensely impractical.
You would need at least two leisure batteries, one in use, one on charge, and you would have to swap them at least every two days but if you timed it wrong and drained the battery completely you would kill it dead and that would be really expensive. Even for two days worth of charge you are barely looking at move than a basic frost-killing setting on a 12v heater. I doubt you'd even notice it working unless you stood right over it.
I then tried a little butane gas cylinder camping heater but it was uneconomical and only created a warm area of about three foot diameter and I move around a lot more than that in my shed.
I ended up opting for an Aladdin paraffin heater for my shed because I have good ventilation and I buy paraffin for the GH heaters so it's no bother but if I didn't mind lugging the cylinder back and forth for refil I would have opted for a calor-gas heater as being the most cost-effective and safest option.
Unless you have electricity then I would also go for Paraffin heaters: they do keep a GH or shed frost free - not warm.
I have changed to mains electricity for my greenhouse this winter because paraffin is now soooo expensive, plus you can no longer take the container to be filled. you have to buy the stuff in a new container each time. The heater I have is the equivalent of a 100 watt bulb and has a frost detector wired in to the system.
A friend down the road with a large shed/workshop has installed a smallish stove with chimney for wood/coal. My studio has a calor gas heater, which I only use if I really have to as it smells and exudes humidity.
Silly Q but why do you want heating in your shed?
The numbers don't really work out for battery-powered heating, Nick. A typical 12V car battery is rated at about 50Ah which means it can supply 0.6kWh. A household single bar electric fire is rated at about 1kWh which would mean (if you managed to find a 12V powered heater of the same rating) it would only last for 36 minutes before the car battery was completely flat and needed a recharge (which would take several hours, say 8 or so.) You'd also have to keep lugging car batteries around (although I suppose that would keep you warm!)
I'm lucky, Artjak, because the garage in my village still dispenses paraffin from the pump so I have big metal army jerry cans full of the stuff. I'd love to install electric though, particularly to dispel the humidity problem, but even given the cost of paraffin versus electric it would take over ten years to break even given the distance my shed and GH are from the mains. Unfortunately I'm married to an accountant who, faced with my plaintive request for mains electric, produced a spreadsheet proving beyond doubt that it wasn't a viable idea.
I'm very tempted by the idea of a woodstove but don't like the idea of leaving it unattended between the time I leave the shed and when it goes out completely. I just know I'd end up running back down to check on it every half hour or so and, believe me, I get enough exercise going up and down the hill otherwise known as our garden without adding a half dozen extra climbs every day.
if you have mains.. use what I do, panel heaters.. I have 2 heating 3/4 of my 12 foot x 10 foot greenhouse. Yes I have bubblewrapped the glass and made a 'door' of sorts, coupled with a plugin thermostat, costs pennies a day to run and keeps GH at 7-8 C.
I also have two panel heaters inside my shed, again rigged to a plugin thermostat, keeps my shed.. well workshop, (maybe size of a single car garage!) nice and happy at 18! again pennies a day to run all day.I looked at parafin, infact i got several heaters from older relatives, but for me the condensation was too much, and also they costed out more than the panels..
heating for sheds for 8p per day
I run tealights in a pot in my mini greenhouse when its going to be really really cold overnight if I am growing sweetpeas. It does work but my main fear is I cause a fire so I don't use them if its windy.