Thread: Shed heating options

Is it possible to install sisilation to an existing tin shed without removing the roof sheets?

I lived in Canberra for 12 years before moving to Melbourne. I found the air was so dry there that moisture/rust was never a problem. At the time I was using a gas blow heater similar to a Jetfire (ie un-flued). Would be interested to hear if Ewan suffers from moisture problems.

I think any form of gas heating will work for the OP. I definitely would avoid reverse cycle. We had reverse cycle where I worked in Canberra and they spent a lot of the time defrosting their coils. While that's happening you get not heat from them.

Chris

Apologies for the garbled reply last night, was writing from my tablet and it was a PITA.

Anyway, Gas isnt really appealing as I hate running out of the stuff, dont want to rent big bottles, and dont like the idea of dragging heavy cylinders around my shed....the units attached no doubt would work but they seem quite bulky too...and I feel my shed is already cluttered enough with all my toys in there.

Fire would be cheap but as pointed out...it takes time to get cranking which defeats the purpose.

The units linked to on ebay were electric blow heaters....theres a 3000w one on there that will cost me 60c an hour to run, and a 5000w 3 phase one that will cost me $1 an hour to run. Both have a half setting also. The 3000w one is $115 delivered, the 5000w one is $180 delivered.

Has anyone used or seen these in action? Do you think I need the 5000w one for a 45sqm shed or could I get away with the 3000w one?

Brendan

Originally Posted by jack620

I think the heat pump efficiency thing is overstated. I have 2 Daikin inverter ducted reverse cycle air conditioners in my home. They are frighteningly expensive to run.
.

if you calculate the heat output (to occupied space) V $'s input you will find that heatpumps are the most efficient..latest models are getting cop's of +3.00 at standard design conditions ...that means for very $ input you get over $3.00 worth of heat (when compared to electric element)

gas (natural (ng) and not lpg) runs a close second but you only get heating...no cooling

I think wood comes next and assumes a high efficieny combustion wood heater/stove

electric element is basically 100% efficient..for every $ input you get $1.00 worth of heat

can not recall where LPG fits in but its definitely very dear

and then comes open fire pace...way way down on the list as most heat goes to atmosphere via the stack

personally, I have a 4 panel suparay.....and for info only, these dont heat the air directly..they work by the items eg lathe, mill, and other stuff in your shed absorbing the infrared rays and then those items release that heat back into the space by convection.

I would go the big one Brendan. 5000W is equivalent to 18MJ/hr. given that you have a large un-insulated tin shed in the coldest city in Oz, you will want plenty of output. Any chance you can run a mains gas pipe to the shed? How far is the shed from the nearest gas pipe on the house?

Originally Posted by 19brendan81

Apologies for the garbled reply last night, was writing from my tablet and it was a PITA.

Anyway, Gas isnt really appealing as I hate running out of the stuff, dont want to rent big bottles, and dont like the idea of dragging heavy cylinders around my shed....the units attached no doubt would work but they seem quite bulky too...and I feel my shed is already cluttered enough with all my toys in there.

Fire would be cheap but as pointed out...it takes time to get cranking which defeats the purpose.

The units linked to on ebay were electric blow heaters....theres a 3000w one on there that will cost me 60c an hour to run, and a 5000w 3 phase one that will cost me $1 an hour to run. Both have a half setting also. The 3000w one is $115 delivered, the 5000w one is $180 delivered.

Has anyone used or seen these in action? Do you think I need the 5000w one for a 45sqm shed or could I get away with the 3000w one?

Brendan

rough rule of thumb for heating a standard house is to allow 100watts / square metre...its going to be much higher for a non insulated metal shed

If your going to use electricty as the fuel then you must consider capital cost of heatpump Versus long term fuel bill
Insulation is important if you want to reduce fuel bill.
If working in your shed you can always layer up and set heatpump thermostat down to say 15 to help reduce energy cost

Eskimo,
I'm no expert in the area, but my understanding is that the efficiency of heat pumps drops as ambient temperature drops. In Canberra, where it regularly gets below 0C in winter, they spend a significant amount of time and energy defrosting their coils. At what ambient temp were the figures you quoted measured?
Chris

Interesting observation that unflued gas heaters put a lot of moisture in to the air. This would explain the problems I am having, even though I always run the heater with good ventilation.
Maybe I should keep this Supagas heater for outdoor use only and look into a flued LPG gas heater.

any one considered buying or Building one of these

GAS_TUBE_RADIANT_HEATER.jpg



they are the heaters... you see when you first walk in to bumblings

looks like all you need as a blower, gas, a mixer and some length of Gal pipe ... Can't be that hard surely ...??

"Any chance you can run a mains gas pipe to the shed? How far is the shed from the nearest gas pipe on the house?"

About 1 meter...

Re electric - Im also leaning towards the bigger one....id rather be over gunned than under gunned. For intermediate nights I have a little kerosene heater that I fired up for the first time last night...it throws out a reasonable amount of radiant heat...but pumps out water vapor in the process.

Re layering up - yeah this is fine for most work I do, however I will only work on my lathe in short sleeves...which can be a touch nippy when its under 10 degrees in the shed, which is pretty much every night of the year for July and August, and most of June. I think it was 8 degrees when I was in there at 7.30pm last night.

Brendan

Chris,
No moisture problems here at all. Love it, I used to live down the south coast and everything rusted.

Our house aircon stops pretty regularly to defrost, we can have ice here by 9 easily some nights. Brendan, if your planning to run it at night mostly I would not bother with heatpump tech, the cop gets pretty low once the air gets below 0.

100w per m2 is pretty standard for heating in an insulated house. Get yourself a roll of aircell and line the whole shed, it will make a massive difference....although this morning its cold everywhere....where is that Sun?

Cheers,
Ew

Re insulation - 1/3rd of the roof is currently insulated with batts and timber cladding, same with the walls....the back third of my shed used to be an office. Front two thirds is not though...I will look into putting something up there...what is the product you reccomend?

Re sun - hours away by the look of things. Just checked BOM and it was probably more like 5 degrees when I was in my shed last night. I knew it was chilly cos my breath was starting to mist.

Brendan

Originally Posted by eskimo

can not recall where LPG fits in but its definitely very dear

At Brendans price of $0.20kWh it comes in pretty much the same. (if the gas usage rate from supgas is correct)My Shed is about 12*8 with a lot of cast iron in it, it take maybe 30 minutes to take the chill off. The owner of the heaters shed is larger but has a lot less stuff in it and in 30 minutes its heading towards t-shirt time lol. Cant say I have noticed any change in moisture problems since using the heater.

Brendan I think it would take a fair while for 3kW to make a lot of difference to the whole shed. But the would be easy to cart about to where you are. What my heat will do in 30 minutes would take your 3kW heater 6 hours.
Don't you have a couple of little fan heaters? I have three kicking about. As Eskimo says a W is a W as far as electric elements go. Most little fan heaters are about 2000W so try and couple and see if you notice a difference. I've tired them from time to time and while they help I wouldnt call them the answer.

Stuart

My two burner natural gas powered forge outputs 21kW which warms the shed up VERY quicklyso that I had to boost my 300 cfm ventilation to >1000 cfm ventilation and it is still not really enough. I had though about employing the 1250 cfm of my DC but that's 2.4kw of energy up the spout but I will have to do that in summer.
Interestingly I didn't notice any problems with condensation, probably because I was using ventilation.

Not that it gets that cold here or that we even worry about it.
The only time we have turned on heaters inside during the last 3 years has been when we have had visitors.
During the last couple of weeks our house has been 14º and 17º inside and we just wear a windcheater (for me its the manky one with the melted sleeves)

"Most little fan heaters are about 2000W so try and couple and see if you notice a difference"

Thats a good point Stuart....I could probably buy a couple of those dirt cheap locally and at least have them at either end of the garage or something. That 3 phase one is beefy, but an extension cord for it so that I can move it around the shed would double the cost.