Recommendations for a greenhouse electric heater please

For the discussion of topics related to the conservation, cultivation, propagation and exhibition of cacti & other succulents.
Forum rules
For the discussion of topics related to the conservation, cultivation, propagation and exhibition of cacti & other succulents only.

Please respect all forum members opinions and if you can't make a civil reply, don't reply!
FaeLLe
BCSS Member
Posts: 339
Joined: 24 Feb 2016
Branch: DARTFORD
Country: UK
Role within the BCSS: Member

Recommendations for a greenhouse electric heater please

Post by FaeLLe » Thu Feb 01, 2018 10:31 am

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.
JaneO
Registered Guest
Posts: 894
Joined: 22 Jan 2009

Re: Recommendations for a greenhouse electric heater please

Post by JaneO » Thu Feb 01, 2018 12:43 pm

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
BCSS Member
Posts: 339
Joined: 24 Feb 2016
Branch: DARTFORD
Country: UK
Role within the BCSS: Member

Re: Recommendations for a greenhouse electric heater please

Post by FaeLLe » Thu Feb 01, 2018 2:39 pm

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!
User avatar
habanerocat
BCSS Member
Posts: 222
Joined: 02 Jun 2012
Branch: DUBLIN
Country: Ireland
Role within the BCSS: Member
Location: Ireland
Contact:

Re: Recommendations for a greenhouse electric heater please

Post by habanerocat » Thu Feb 01, 2018 3:19 pm

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......
Cidermanrolls
BCSS Member
Posts: 73
Joined: 21 Nov 2016
Branch: LINCOLN
Country: England
Role within the BCSS: Member

Re: Recommendations for a greenhouse electric heater please

Post by Cidermanrolls » Thu Feb 01, 2018 7:15 pm

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.
User avatar
ralphrmartin
BCSS Member
Posts: 2310
Joined: 11 Jan 2007
Branch: SOUTH WALES
Country: UK
Role within the BCSS: Branch President
Location: Cardiff
Contact:

Re: Recommendations for a greenhouse electric heater please

Post by ralphrmartin » Thu Feb 01, 2018 8:54 pm

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
http://www.rrm.me.uk/Cacti/cacti.html

Members visiting the Llyn Peninsula are welcome to come and see my collection.

My Field Number Database is now hosted by the BCSS: see
http://www.fieldnos.bcss.org.uk
User avatar
Peter
BCSS Member
Posts: 2496
Joined: 22 Mar 2007
Branch: SHREWSBURY
Country: UK
Role within the BCSS: Member
Location: Whitchurch, Shropshire

Re: Recommendations for a greenhouse electric heater please

Post by Peter » Thu Feb 01, 2018 9:08 pm

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.
User avatar
Mafate79
Registered Guest
Posts: 126
Joined: 23 Feb 2015
Branch: None
Country: France
Location: France

Re: Recommendations for a greenhouse electric heater please

Post by Mafate79 » Thu Feb 01, 2018 10:29 pm

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
topsy
BCSS Trustee
Posts: 648
Joined: 20 Sep 2007

Re: Recommendations for a greenhouse electric heater please

Post by topsy » Fri Feb 02, 2018 9:47 am

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
User avatar
agavedave
Registered Guest
Posts: 128
Joined: 21 Aug 2015
Branch: None
Country: UK
Location: East Anglia
Contact:

Re: Recommendations for a greenhouse electric heater please

Post by agavedave » Fri Feb 02, 2018 12:27 pm

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
Post Reply