Greenhouse Heating

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Guy

Re: Greenhouse Heating

Post by Guy »

Mick C, yes it should be fairly good at 5c, but i'd still prefer an external thermostat. Dave's explanation is correct if all was equal, but when heaters were tested by Garden Which? in the same size greenhouses, many of the same wattage heaters were useless as they are unreliable or don't circulate properly or have poor thermostats. Not all 2Kw heaters are identical.
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Mick C
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Re: Greenhouse Heating

Post by Mick C »

OK Guy, thanks again for the info.
kentgardener

Re: Greenhouse Heating

Post by kentgardener »

helen wrote:Am thinking of sectioning off part of the greenhouse (I've got a big 'un), and I'll add heat to that section, rather than the whole thing. So, I can easily create a 'tent' from bubblewrap, or build something with more expensive polycarbonate. Just not sure what yet.

Anyone done this before?
Hi Helen

I used to have a few overlapping 'curtains' of bubble wrap that I could walk through for the end of the biggest greenhouse - it sectioned off the last 8 ft or so. I had one heater in the main bit set to a low temp (a couple of degrees) - and a seperate heater in the smaller curtained off bit that was set to 5c. I am trying to remember (after a Friday work drink session drunken_smilie1 ) how I did it. I remember that either propane or butane freezes at low temps. So I had a butane heater in one bit and a propane heater in the other bit. everything seemed to survive happily and it didn't cost a packet.

cheers

John
Frank
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Re: Greenhouse Heating

Post by Frank »

I remember that either propane or butane freezes at low temps.
It's butane John that freezes = blue bottle.......
Don

Re: Greenhouse Heating

Post by Don »

Bloody pseudo scientists :lol: It's Butane that has a BOILING point of about-0.5C. It freezes at about -140C. In other words even on a coldish day Butane is not very good at vapourising.
Frank
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Re: Greenhouse Heating

Post by Frank »

What, you're saying oop North it doesn't get to -140C :lol: :lol: I'm sure you're right Don, I was just spreading misinformation picked up on one of these plant websites long defunct :wink:
Libby

Re: Greenhouse Heating

Post by Libby »

wheres the best place to get an external thermostat for frost free fan heaters from???
Linden

Re: Aluminium vs. wooden frame greenhouse

Post by Linden »

Sorry Dave I didn't explain very well there - I meant we'd take it apart to move it if necessary for access to the manhole,hence timber base rather than concrete. We've now decided anyway to go for a smaller 6' x 6' to make access to the garden easier and safer, and tempered glass was definitely on the agenda from the start. Next step - any advice on heaters? I'm wondering if we'd get better air circulation if we get a more expensive one that we can hang from the roof? We can get power in easily enough from the summerhouse, there's already an outdoor socket there. I read that some plants can get scorched by a floor fan heater, and the fan goes off when the heater goes off. A better one will keep the fan on low all the time. Any hints gratefully received icon_salut
dave2166

Re: Aluminium vs. wooden frame greenhouse

Post by dave2166 »

heaters....mmmmmmmmm. that was the next thing on the list of things to buy... dont think the cheapie ones are much good, IMHO. the stats arent accurate enough and can end up with wider fluctucations in temps than you need. not sure about the roof hanging methodd, cos hot air rises which is great but the plants at the bottom will not feel the effect until it cools down and then its a bit late. i was going to go floor, and have flexibility to adjudt to staging and angles. from what little i have researched the more pro style vary widely on the web, try these sites

http://www.greenhousewarehouse.com/Elec ... 21CT8.aspx

http://www.isgreenhouses.co.uk/greenhou ... rs_6_1.htm

http://www.garden4less.co.uk/greenhouse-heaters.asp

http://www.greenhousepeople.co.uk/green ... e-heaters/
Linden

Re: Aluminium vs. wooden frame greenhouse

Post by Linden »

I agree, but when I read about them (can't remember where out of all the pages I've trawled in the last few days!) it said that if you have a good fan, it's less damaging to the plants as the heat is fanned round the greenhouse rather than chancing scorching plants at the bottom. I rather fancy this one: http://www.garden4less.co.uk/phoenix-el ... heater.asp but will continue researching icon_scratch
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Dave Brown
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Re: Greenhouse Heating

Post by Dave Brown »

Libby wrote:wheres the best place to get an external thermostat for frost free fan heaters from???
I don't know about a best place, but check THIS PLACE :lol:

Lots of goodies from Thermostats and controllers, to heat mats and heat bulbs. They also do a solar powered temperature probe which may be useful for monitoring soil temperature :DD
Best regards
Dave
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Roll on summer.....
http://www.hardytropicals.co.uk
dave2166

Re: Aluminium vs. wooden frame greenhouse

Post by dave2166 »

Linden, i fancy that too !!!!, now got to figure if i
1- order it and lie about the price
2 - order it and tell her it will last for years so its an investment
3 - order it and say it will be more economic on electricity
4 - order it and be damned....

working in ventilation myself, its more the volume of air movement than the heat as such, as a constant moving air stream will give better distribution and fewer cold spots, hence less cutting in and out.
also those cheap fan heaters are like putting your hand in front of a hot air gun.... too hot, the more air blowing the better as that keeps the heat manageable at the output point
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Dave Brown
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Re: Greenhouse Heating Good ventilation required

Post by Dave Brown »

Linden, I don't know about Gardening 4 Less :lol: , but that heater is 3 time the price of my new polytunnel :shock: . I would just stand a fan behind the heater and leave this running. By comparison running a fan is a fraction of the cost of heating, it will help avoid condensation and rot, will blow greenhouse air across the heater sensor giving a far more accurate thermostatic control, and assist in distributing the heat more evenly.

I would hope to keep my poly frost free for a winter for far less than that heater costs :wink:
Best regards
Dave
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Roll on summer.....
http://www.hardytropicals.co.uk
Linden

Re: Greenhouse Heating

Post by Linden »

Dave2166 that was what the article said, nice to have it confirmed by an expert! I agree DaveB about the price, it was just the bit about the moving air that impressed me, and having it at the top of the greenhouse so it'll move warm air down again rather than losing it. A fan behind the heater looks like it would work too.. We just need to bit the bullet and get the stuff ordered or the frost'll come and we'll be too late anyway :lol:
musa_monkey

Re: Greenhouse Heating

Post by musa_monkey »

I managed to pickup a new greenhouse thermostatic electric fan heater in Wyvale at the week end for £10 so a nice bargain :D.

i am aware that the stats on these things are not always accurate so am considering getting an electronic plug in stat for it that i could also use elsewhere.

Anyone used one of these before ?

http://www.tlc-direct.co.uk/Main_Index/ ... index.html
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