Recommendations for a greenhouse electric heater please

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FaeLLe
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Recommendations for a greenhouse electric heater please

Post by FaeLLe »

Hi,

Based on feedback from folks on here I decided to get armoured cable laid around my fence till the place where I plan to fix my greenhouse.

Can someone suggest a model and specification of heater to heat my greenhouse which is around (8x12 approx. or smaller), need a digital thermostat one I believe. Will a 3kwH one do?

I would like to run it really hot (15 celcius, I heard this should be fine?) due to my love for caudiciforms...

Also how does everyone manage failure of the heating system at night, paraffin backup?

Thanks.
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Re: Recommendations for a greenhouse electric heater please

Post by JaneO »

Hi,
https://www.amazon.co.uk/Bio-Green-Heat ... b3cc27eeaf

This is one of the best but not cheap at £135 on Amazon. It seems to offer what you want but only 2w not 3.
Good luck
FaeLLe
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Re: Recommendations for a greenhouse electric heater please

Post by FaeLLe »

JaneO wrote:Hi,
https://www.amazon.co.uk/Bio-Green-Heat ... b3cc27eeaf

This is one of the best but not cheap at £135 on Amazon. It seems to offer what you want but only 2w not 3.
Good luck
Thanks, looks like what I need!
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Re: Recommendations for a greenhouse electric heater please

Post by habanerocat »

FaeLLe wrote:
Also how does everyone manage failure of the heating system at night, paraffin backup?

Thanks.
All depends on how it's wired.

Assuming you have a dedicated MCB for the mains cable you can mount an auxiliary contact on the side of this. The auxiliary can drive a lamp or bell in the house. Whatever is practical for you. The tripping of the MCB would be your main fault concern. Any electrician could wire this.

Next level up would be visible indication that all is ok in the greenhouse. This could be as simple as mounting the digital thermostat so that it is visible from the back window. Of a low wattage neon lamp perhaps.

Advanced level would be an on-site temperature monitoring alarm unit. It gets a bit complicated. There has been previous threads here before. Try a search or a ask a more detailed question maybe.

I wouldn't be into paraffin backup myself......
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Re: Recommendations for a greenhouse electric heater please

Post by Cidermanrolls »

I like the bio green Phoenix. It's more expensive, but at 2.8kw it should do what you need, if you insulate well. I use 4mm twin wall polycarbonate insulation and you can buy it in greenhouse panels size off eBay.
My 6x8 "hot house" is set to just over 10c and holds steady with the heater on its 1kW setting (I limit the output as I have three greenhouses running off one common supply main and don't want to risk expensive overload damage!)
I'm not sure you need a digital thermostat. The Phoenix has what I think they call a capillary thermostat and it works very well with little hysteresis. My oldest one of these heaters is well over five years old and showing no signs of wear.
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Re: Recommendations for a greenhouse electric heater please

Post by ralphrmartin »

I have an old 3kW Parwin heater with thermostat, which should do the job. (I used 2 to heat a 10 x 20 greenhouse set to about 5C at one end and 7 C at the other, but the second one rarely came on).

They are pretty reliable, but alas made no more.

You can run the fan without the heater, too, which is useful for ventilation.

How does £50 + delivery charge by Hermes or other suitable budget parcel service?

(In fact, as you can see, I've got a couple if you want a backup :grin: - and I'll do free delivery if you take both).

PM me if interested.
Ralph Martin
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Peter
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Re: Recommendations for a greenhouse electric heater please

Post by Peter »

This year for the first time since I bought it some eight years ago as a back-up heater, I had reason to use my Calor gas fired heater. Incredibly, it started straight away and the heat it gave off was tremendous, even at a low setting. It certainly surprised me about how much it warmed my 40ft x 22ft greenhouse.

I really cannot recommend gas heaters enough for back-up use and a small one would easily suffice, coupled with a small gas bottle - which last a long time given the low heat setting.
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Re: Recommendations for a greenhouse electric heater please

Post by Mafate79 »

Hello,

I think that I use the same heater than Cidermanrolls: see here on Amazon.

I only had it for a year but I read a lot of positive opinions about it on the web before buying and it makes the job. The only concern are its grids at each end that rust slightly
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Re: Recommendations for a greenhouse electric heater please

Post by topsy »

Hi,

We use LPG heating all the time with the addition of an electric heater. Being out in the countryside with overhead electricity supply we cannot rely on the supply being interrupted. I would question whether you need the temperature that you are planning for. Yes a lot of (but not all) caudiciforms need extra heat, but unless you have very large plants wouldn't it be simpler and cheaper to create an area in the greenhouse which you could keep hotter without increasing the heat in the whole of the greenhouse? A hotbox or hot area?

Regards, Suzanne
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Re: Recommendations for a greenhouse electric heater please

Post by agavedave »

I use an ordinary domestic fan heater on an electronic thermostat and another heater on it's own thermostat set a little lower than the main one. No watering happens Oct-April so getting the heater wet/watered is not an issue for me. Though I'm only keeping temps above 3.5°C 1Kw is more than enough in a 8x10 bubble wrapped GH.

Inside the house there is a temperature display powered from the same rcd as the cable to the GH. If the power fails and alarm sounds.

The load sensor and sensors in the GH all feed into a data logger so I can monitor its performance, I just can't afford to over heat even by a couple of degrees because the cost would soon escalate.

I remember seeing some gadget as a power fail alarm for freezers quite some time ago that had a battery and plugged into the same socket as the freezer, you might find something if you look around.

They can even send you a text when the temperature goes outside limits
https://www.uk-automation.co.uk/envirot ... t-message/

Regards
Dave
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