GardenBanter.co.uk - View Single Post

John McMillan · 16-01-2007, 10:33 PM posted to uk.rec.gardening

In article ,
"BoyPete" wrote:

wrote:
BoyPete wrote:
wrote:
so it would just be the cost of a light turned on 24-7? How much
does that equate to I wonder?

Judith at home in England

Obviously it depends on your energy supplier and wattage,, but
around £1.20 a month for 'a light bulb'. Info courtesy of Google.
--
ßôyþëtë

I wonder if you could use the low energy bulbs making that around
what, say 50p a month. I have a Halls greenhouse, I think its about
8 x 8. My new paraffin heater blew up and I don't want another.
Would 2 x low energy, 100 watt bulbs be adequate to heat the
greenhouse so that I could use it now?

Judith at home in Norwich

No, the electricity is 'used' to create light. The tubes I spoke of use all
the electricity to produce heat. Do you remember the old style portable
heaters that used a long coil of wire that glowed red?....similar concept,
but safely enclosed.

Heck, all the electricity ends up as heat anyway. If its a transparent
polytunnel then maybe some of the light will escape and not heat the
tunnel but even in an energy efficient bulb most of the power goes
directly to heat without going through light first. So if you use a low
energy bulb it will simply produce less heat. I don't know how
big the polytunnel is - or how well insulated (is it bubblewrap lined?)
but I get the feeling that 100 watt wouldn't make much difference to
the temperature. Most greenhouse heaters are 2kilowatt and up.
There's some nice thermostatically controlled heater tape thats intended
for underheating beds and greenhouse staging.
However, its a nice warm winter this year.