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Greenhouse parrafin heater ????

Discussion in 'Greenhouse Growing' started by Spruce, Feb 4, 2012.

  1. Spruce

    Spruce Buzzed off, wont be back

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    Hi all

    Was going to put this in the other thread about greenhose heaters, but reading through never gave me a answer if the weather carries on like this I was thinking of getting a parrafin heater only wont it to keep the frost out, greenhouse only small but it is cedar and with toughned glass so it is a lot warmer 8 x 6 I supose

    Anyone any ideas of which one would be suitable

    Spruce
     
  2. pete

    pete Growing a bit of this and a bit of that....

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    Spruce as said on the other thread, the price of paraffin is ridiculous these days.
    Even electricity is cheaper, and more controllable.

    But I know its a problem to get the cables installed, there are ways of doing it, but I'd get slaughtered if I mentioned them. :D
     
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    • Kristen

      Kristen Under gardener

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      I think, personally, that there are several problems with paraffin heaters

      Here are my thoughts on greenhouse heaters:

      Paraffin Greenhouse Heaters

      1) Paraffin generates a lot of condensation (more than Gas, and Electricity doesn't have that problem)

      2) Paraffin heaters don't have thermostatic control, so you have to light it when you think it may be needed, and then it runs until you turn it off, whether cold or not :(, or it runs out of fuel

      3) Paraffin heaters will turn the whole greenhouse black if the wick is not trimmed properly. This is most likely to be a problem if you ask a mate to "just light the greenhouse heater if it gets really cold"

      4) Paraffin seems to be very expensive nowadays (relatively speaking). If you can buy it in bulk, somewhere where you take your own container, you might get a better price.

      5) After lighting you have to go back a second time to check & adjust the wick.

      These cost between £20 - £40 and will provide frost protection (only) for 6' x 6' to 8' x 6'; they burn between 0.5 Litres and 1.2 Litres per day

      [​IMG]

      Models: http://www.greenhousewarehouse.com/categorylist/greenhouse-heaters-paraffin-heaters/

      Electric Greenhouse Heaters

      My first choice would be electric, but that only works if you have electricity in the greenhouse of course!

      1) Buy a proper thermostat (if the heater does not have a accurate one already). Its very doubtful that the one in "economy range" heaters is accurate, and you will save a lot of electricity / money by the heater only achieving the desired temperature, and its hysteresis not over/under-shooting

      2) Electricity is the most expensive type of energy for heating, but for frost-protection and with a quality thermostat, it will be the cheapest overall

      3) Fan will move the air, which will help with moulds etc. in the Winter. If you are likely to have a problem with humidity (e.g. you have to stuff the greenhouse full! over the Winter) then choose a fan heater with a blower-only mode so you can use that to circulate the air on days when heating is not required.

      The small ones are 2kW @ £40 and able to provide decent heat in a 8' x 6', and frost-protection for 10' x 12'. However, they are not very efficient, thermostats are crude (so hysteresis will over/under-shoot) and thus will use more electricity than a more upmarket model

      [​IMG]

      More upmarket models around £200 much more efficient (i.e. use less energy) and powerful fans so no cold-spots in the corners :thumb: This particular one also has a quality thermostat build in.

      http://images.esellerpro.com/2265/I/121/1/medscaleheat-elec-phoe.jpg

      Consider a quality thermostat for the cheaper models @ £50 - likely to save you the extra cost in reduced electricity use over 3 or 4 years - and an electricity meter - so you know how much it is costing and how long it is coming on for.

      I wouldn't bother with tubular heaters, or any other type of convection heating. This tuular heater is £25 and outputs 60watts (yes - that LITTLE !!). I've never seen one with a thermostat, so you'd need to get one of those too.

      [​IMG]

      Electric heater models: http://www.greenhousewarehouse.com/categorylist/greenhouse-heaters-electric-heaters/


      Propane Gas Greenhouse Heaters

      1) Should be cheaper than Paraffin (and may be cheaper than Electricity if you want to maintain, say, 10C rather than just frost-protection)

      2) Can be thermostatically controlled, but the thermostats tend to be a bit crude - so some over/under-shooting of target temperature

      3) Risk that a gas bottle runs out, or the pilot light goes out, and you have no heating! You can fix the first by having two bottles and a change-over valve (My fix to this problem is to move the gas bottle to the kitchen-cooker when it is getting low, as we have a bottle-gas "range" cooker in our kitchen)

      4) You have the initial cost of the gas bottle "deposit". However, you may already have a Propane gas bottle for Summer Bar-B-Q etc.

      5) Some condensation (but less than Paraffin)

      Typical model is 1.9Kw @ £75 brand name Lifestyle although if you are searching on eBay also look for "Eden" which was the original brand name. Suitable for heating 8' x 6' and frost-protection in 10' x 8'

      [​IMG]
      http://www.greenhousewarehouse.com/categorylist/greenhouse-heaters-gas-heaters/

      Insulation

      Cheapest form of heating is to use less heating!! so insulate the greenhouse carefully with bubble-wrap. Tape up the joins. If you have cropping wires you can drape the bubble-wrap over them for support, and if not there are plastic "offsets" that will either fix into the channels in aluminium glazing bars, or have suckers that stick onto the glass, and then you "popper" the bubble-wrap to the offsets.

      The offsets look like this:

      [​IMG]

      Examples: http://www.greenhousewarehouse.com/categorylist/greenhouse-insulation/
       
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      • Scrungee

        Scrungee Well known for it

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        I would only use paraffin for somewhere where either the cost of cabling would be prohibitive, or would be too insecure to leave a gas heater/bottle/regulator, but I do have these old blue-flame Aladdin heaters for use in polytunnels, and I've also got the metal extension tubes for them, spare larger wickcarrier/chimney, wicks, etc.

        [​IMG]


        P.S. For greenhouse heating at home I use propane despite having electrcity laid down the garden because I'd lose the lot in a power cut and we get too many of those in this village.
         
      • Spruce

        Spruce Buzzed off, wont be back

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        Now thats what I was after do they still sell these ?? they look as it should be on the antique road show:heehee:

        Thanks everyone I will probably only use it when the weather goes like this so hopfully just a couple of weeks a year but for the coast and what I have in the greenhose I think I will need to do somthing , I cant lose more stuff this year as well that will be 3 years on the trot

        Spruce
         
      • Kristen

        Kristen Under gardener

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        I've gone back and "topped up" my earlier post.
         
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        • Scrungee

          Scrungee Well known for it

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          I've seen them on ebay, but have never come across one at a car boot sale yet (and I visit quite a few). Being 'blue-flame' with a circular wick they are more fuel efficient and emit less smoke than those with flat wicks like cheap Parasene heaters. Mine are from the 1950's and wicks and trimmers are still available.

          I'll get the extension tubes out of storage and take some more pics of them in case it helps anybody spot them at a boot sale. They're about 3" dia, fit on the male tubular stubs either side at the top, have legs and extend the heating by about 3 feet either side of the heater. I'd buy another one myself if I saw one going cheap.
           
        • Spruce

          Spruce Buzzed off, wont be back

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          What would be a ok price on ebay I was looking at Bio Green Warmax power 5, talk about ££ if you dont have a nose around and see what what

          Spruce
           
        • Scrungee

          Scrungee Well known for it

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          There's none on ebay at present, probably not for some time, I wouldn't pay the prices asked when I have seen them, and would want to look it over before committing to buy. But if I found one at a car boot with some wear left in the wick, that had a wick trimmer and no sign of leakage from the fuel tank, I'd pay as much as new one of those Bio Green (or Parasene) heaters (and that's without any Aladdin heater extension tubes).

          Any other Aladdin blue-flame enthusiasts out there?

          And are there actually any 'modern' blue-flame paraffin heaters available these days?
           
        • Kristen

          Kristen Under gardener

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          When I was a kid the only "central heating" we had in the house was "oil-heaters", with circular wicks.

          I can't believe that paraffin would be more cost effective than gas or electricity these days, but I'd be happy to be proven wrong.

          They probably give off some CO2 which, if sufficient light, would help with growth? Pretty sure we used to burn Paraffin-for-CO2 (in commercial greenhouses) in the early '70's
           
        • moonraker

          moonraker Gardener

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          Heaters,

          Hi pete,
          Ive a greenhouse thats 12x8feet and like many other people ive given a lot of thought as to when to heat it up, ie cost is the big thing here, and secondly power cuts, It's all very well having electric "as i have" until one morning you go out to the greenhouse only to find the electric company turned the power off during the night and this is a favourit time for this to happen, & all's lost or damaged.

          Now ive been gardening for a long time, it's my hobby, my life and one of the reasons i agreed to come here to france to live (much larger house and garden plus a field that will be my allotment next year at a cost i just couldnt afford in the uk, and we do get a good summer every year here) "We did live in north -wales and summers lasted about 4 weeks"

          Now having said all the back ground stuff ive insulated the greenhouse, i do use electric therm/control, But i also have a paraffin heater but with a difference.

          It has the normal circular wick and the heater holds 1Xgallon of fuel,
          its got the funnel that fits over the wick "but now's the difference"

          all ive just said, fits under a square metal frame and on this frame a large thin copper tube fits, this tube is filled with water and as the heater heats the water the heat spreads around the greenhouse, but when the heater is turned off, the heat is still there until the water cools down & this takes a few hours.

          I bought this heater off an old friend when i had the allotment in the uk and because of this water tank idea it really is a good item to have.

          But what i was going to say or ask is this, how many people are heating the greenhouse through the winter?

          Ive had thoughts on this subject and apart from over wintering the frost free plants and i can use fleece/bubble plus as ive said my greenhouse is fully insulated so these methods seem to work for such plants,

          But if you take into account the cost of buying some early seed sown plants that the gardencentre's are selling near to april/May time and you just carry on growing in your greenhouse when just the night temp needs tobe continued by you!

          Is it really worth heating all through the winter?

          My thought is that for what i save on heating fuel all winter i can buy a lot of plants grown via the garden centre's and let them worry about germination during the winter cold times.

          Dont get me wrong im still itching to start the seed trays off in the spring and ive pots & pots of geranium's in the workshop all doing well, but winter heating the greenhouse i feel is to costly and to risky.

          Whats others thoughts on this subject?:grouphug:
           
        • Kristen

          Kristen Under gardener

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          I have two thoughts :)

          1. I don't know the physics, but I would have thought that heating a "heat sink" (your water-filled copper-tube) means that the hysteresis is greater. So greenhouse gets to temperature, you [or a thermostat, but obviously not for a paraffin heater!] turn off the heat, the heat-sink carries on pumping out heat, temperature continue to rise above the target "max" temperature. In part this doesn't matter because it then takes a while to cool back down to the point where you need to turn the heat back on again [provided the plants don't benefit more from "constant" temperatures], but whilst at the higher temperature the differential to the cold outside is higher, and thus the heat-loss is higher, and overall it takes more energy overall.

          In the case of a paraffin heater (no thermostat) the worst case is that you light it, the night is not very cold, it heats the greenhouse gently all night, at 9am the greenhouse is quite a lot warmer than the "minimum" you are trying to maintain [and possibly your heat-sink is fully-charged], and then the sun comes out during that day and in effect the extra heat you have put in is wasted as it is not "stored" until the next cold night.

          For an electric fan heater I would either want a very accurate thermostat built in or, if that is not included, I would add an external one. They are not cheap (50 quid, ish?) but are likely to repay their cost in saved electricity within a year or two. Similarly heaters with efficient fans / pumps / whatever will be cheaper, long term.

          2. Maybe consider NOT heating / using the greenhouse. You are a bit further South in France, but back here in Blighty you may remember :) that light levels are not good in the Winter. So it may be more optimal to have a grow-room with special lighting, good insulation (easy to do if you are not having to use Glass to get the maximum light input!), and compare the cost of lighting against the cost of heating (and taking into account that, in a glasshouse, natural light will not be enough for you to make a start on your bedding plants early enough in the season to fully steal a march on the garden centres.

          Lets assume that you spend £100 on bedding plants a year, and that you are happy to cover the capital cost of the lights (you don't have to buy a greenhouse heater, and you won't have to insulate the greenhouse with bubble-wrap every year, so we'll swap that for the cost of buying the lights).

          Assume that you will light the seedlings for 8 hours a day for 3 months. My figures are based on memory, so I'm happy for someone else to do a calculation that is more accurate :)

          £100 budget for 8-hours-a-day for 3-months-a-year I calculate would provide 800W of lights. I would say that is equivalent to a floor area of a 6' x 8' greenhouse, maybe a 10' x 8', and you will have more light / growth than a heated greenhouse would get in the early months of the year.

          Having said that, £100 would get you a LOT of electric greenhouse heating in MOST years. In a really cold snap it will be on 24/7, and you may fail to maintain minimum temperature, and a power cut could wipe out your plants if temperature fell low enough in the greenhouse. When tossing-a-coin to decide keep in mind that a power cut is likely in really bad weather - significant snow falls will bring down power lines. You could have a backup Gas/Paraffin heater, but you would need to get an alert (e.g. at 1am !!) that the power had failed

          By comparison with a grow-room a power cut would mean that plants had no light for a day or two. Probably no harmful side effects (freshly germinated seedlings WOULD get leggy, but plants that were a week or two older, or more, should be fine). I'm assuming that the grow-room is insulated, and probably "within" your home, so temperatures won't drop to dangerous levels
           
        • moonraker

          moonraker Gardener

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          Hi and thanks for your view',
          ref the paraffin heating not being controled via therm,

          It's the same problem as over heating the greenhouse via summer temps,
          and for this we have the automatic temp/set window openers!
          I'll be first to say they are not as good as electric devices "But they do work with electric,
          Once you get to know the automatic opening devices you have ! then your in with a chance of having the greenhouse heated.

          Again the heating is all connected with the time of the year ie feb/march are the times when you'll tend to use more of any fuel to heat and you do have to ask yourself what are you using the greenhouse for? IE overwintering shrubs that are not frost hardy? In this case you dont need high temps, but if you intend to start seeds etc then in most cases your looking at 55deg min,

          As i did say i use my workshop to house all the geraniums all winter and the lowest temp in there of an evening is 44deg, and then in the day its around 70 until approx 9pm.
          But im very very lucky to have such a space a lot of the members dont and its these people that the question has to be asked,
          Is it worth it or not to heat all winter?
           
        • pete

          pete Growing a bit of this and a bit of that....

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          I heat in winter only when necessary. :D

          I use an electric fan heater with a remote thermostat, and during the very cold weather of late I've used a tubular heater combined with a small circulation fan as an extra.

          And that is just to maintain frost free conditions for many plants that are in some cases many years old.

          You cant buy age, well you can but its not cheap:D, so I tend to like to hang on to the plants I have rather than keep buying new ones.
          Just my thoughts, but the disposable gardener, (dump it and buy new next year), is a modern concept I've yet to come to terms with.

          I know with electric there is always the chance of a power cut, but where I live its pretty reliable, (fingers crossed), so a power cut of more than a couple of hours is unusual.
          I keep a parrafin heater standing by, but I doubt it would be much use on a really cold night.
          Managed to buy a gallon at the weekend £6.99, stupid prices.:mad:

          I run a propagator for starting early seeds etc. might get it going the weekend, and as the spring progresses I can turn the thermostat on the greenhouse heater up a notch, as the days get warmer and heat is only required during the night.
           
        • Scrungee

          Scrungee Well known for it

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          My village regularly gets power cuts so I initially used (blue flame) paraffin, then propane gas heaters. I used to heat my greenhouses (had 2 then) when a 19kg cylinder was about £12 and abandoned it when they went to £19. Since then I've deferred putting on the heating later and later each year.

          I've recently acquired a 2kw electric heater for a 'bargain' price of approx £11, which I intend using as a backup to my propane heater (they can and do fail), but I'm wondering if I should get a better 'plug in' thermostat for it such as a eBay - Timeguard ET05 Plug-In Electronic Thermostat £18.75 incl P&P - I use one of these to control a high level fan in my shed/workshop to keep summer temps down.

          I've now decided to keep the general temperature lower and put a couple of 40 watt propagators with a higher temperature setting in there so I'm not paying to get the entire greenhouse up to necessary germination temps.

          I also use Bayliss autovents to control window opening, and cannot speak too highly of this company and their products/service - all still made in the U.K.

          And as I stiil have paraffin heaters for emergencies/out of village poly tunnel heating, the best priced paraffin I've found locally is from here:
          £5.70 for 5 litres
           
        • moonraker

          moonraker Gardener

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          All thinking much the same.

          Well having read the verious thoughts on the "heating of the greenhouse's"
          I think we're all thinking along the same lines,

          Ive been to the local garden centre here today and could'nt help but notice the amount of stuff that was'nt moving ie potatoes, they we're selling but not as fast as normal also fruit tree's are cheaper this year than last,

          So all in all the writings on the wall, garden but try to be wise about it.:cool:
           
        • Carl

          Carl Gardener

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          Here`s the thought I had for heating our greenhouse (3 compartment )24 x12 (one compartment 4 foot and 8 foor and one 12 foot ) I intend to heat the 4 foot and the 12 foot section

          Ive got a 5kw Webasto diesel heater (heats water to 80c) and im thi nking of connecting it up to a couple of radiators in the 2 compartments and running it on waste oil throught a timer circuit and stat

          do folks think this ill work ?
           
        • Kristen

          Kristen Under gardener

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          I would find a web site that does a neat-loss calculation for you; you should be able to enter the "thermal efficiency of the building" and thus you would be able to indicate that the "building" is glass, rather than a double-block-with-cavity-fill thermally efficient wall :)

          That will then tell you how big the radiators need to be, and from that you can decide if that is a runner, or not.

          The victorians used to heat their hot houses like that I think? They had large meta pipes in ducts in the floor, covered with a nice decorative grill, and they gave off continuous heat along their length. They may also have run a couple of pipes (above ground) around the perimeter of the house [I can't remember] which would have counteracted the cold of the glass.

          However, the downside I see with this is the hysteresis. The more radiator volume you add, to get the heating effect you need, the more residual hot water is in the system, and the more the temperature will overshoot when the thermostat shuts the heating system off. You might be able to get a fancy control system that "anticipates" the overshoot and turns the heat off before it is reached (and back on before the temperature falls so far that it will undershoot your minimum target)

          If you have 3 compartments then heating the middle one is probably best - insulated by the two either side that will above external ambient temperature.
           
        • Carl

          Carl Gardener

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          the radiator size will be determind by the size of the ones im taking out the house - there free :lol: - as for turning the system on and off im thinking that the greenhouse will be so thermally inefficiant that having it running all night still wont cause it to get too warm in there

          the idea of heating the end compartments was then the center one would also remain frost free and the one with staging in will be the first compartment
           
        • shooting pete

          shooting pete Apprentice Gardener

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