heating system need help choosing

Hi.
I'm looking for some advice /help in choosing a heat source for our greenhouse.

the greenhouse we have is a dig geodesic dome covered with polytunnel polythene. It has a diameter of 6 meters and is 3 meters high.

We are looking to utilise the area more during the year and use it as more of an indoor garden/ chill out area. A nice spot to have a glass or 2 of vino or a bottle of beer in he evenings. The only problem is it gets a bit chilly at nighttime. So we have decided to heat it. But there are a lot of options.
I don't think passive heating alone is enough to have a comfortable temperature. Seeing as we are heating it I plan to keep some tropicals out there to. so we are looking for ideas and pros and cons of supplemental heat.
Initially we were thinking of buying a wood burning stove but there would be a lot of work keeping the fires burning.
Out other options are gas or electric.
Does anybody know how much it would cost to run either. The gas heater would be run on cylinders.
I have priced a 4.2Kw gas heater online and it is pretty reasonable but I'm curious of the running costs before I commit to buying it. I'm not sure if I am aloud to post the brand on the forum.
Otherwise would anyone know roughly the cost of using electric.

Thanks for your help

 

Thanks for the Great Advice I would never have thought of the oil filled heaters. and love the idea that they are silent

Thanks again FC

 

I use an oil filled radiator in my green house . I use it only when the temp is forecast at 6°c or lower. So I think it will be fairly economical . Now I have a standard size GH not a huge Geodome like yours . Do the manufactures not recommend a suitable system for your unit ?

 

Also in your very large GH you may need a mix of heaters and fan-heaters to move the air for ventilation. I open the door on mine and wave a towel around

 

I have had several heating systems over the years coal, paraffin, gas but I found the most efficient is an electric fan heater, however you will need a good thermostat to control it to prevent hysteresis losses. most fan heaters with built in thermostats wildly over/undershoot required temp.
I have a electricity monitor and using the fan heater with my thermostat reduces costs by 60%
(proved with trial) My present greenhouse 6ft 6 x 16ft
I use a 3Kw fan heater for the reasons stated by fat controller above.
I use a bio green thermo 2 thermostat which is very similar to those inkbirds above only mine cost twice what they are.
Hope this helps Alex

 

I use a gas heater but only because it is affordable natural gas and electricity is far too expensive over here, to use for heating.

As others said, air circulation makes the biggest impact to how much it costs to heat a greenhouse. I have ceiling fans operated by solar power supplied batteries. These operate on the 1/2 hour for a few minutes which works out very well for keeping the heat off the ceiling and in turn, the heater cycles less frequently.

 

Your roof covering, is it just a single skin or double ? if the former the heat loss will be high.
Though do you get many frosts or snow in the west of Ireland or is your climate more like Cornwall and Devon ?

As said, an electronic thermostat will be might better than typical inbuilt mechanical ones.

With the height of the dome you might be better fitting a ceiling type for fan, to push the rising heat back down in winter and to aid cooling in summer.

 

oth

As heat loss through a single skin of polythene is phenomenal [1] compared to heating a glazed greenhouse, I have only attempted to heat polytunnels when there's been an exceptionally late cold spell in May, or for just a couple of days of cold weather in early autumn that would be sufficient to keep the crops inside going for several more weeks after normal temps resumed.


[1] I have put temperature data loggers in both my greenhouse and polytunnels. The temperatures in the tunnels still crash around dawn, even with heating.

 

Hi HarryS I think 6degrees when not in use will probably be the cut off point. Might look at 10 when I get a better idea of the cost difference.
Unfortunately I am the manufacturer its a home made one I put made a few years ago !

 

Cheers Alex yep that helps a lot gives an idea of the size of heater I may need.
I ordered on of those Inkbirds on Fat Controlers recommendation and eagerly awaiting its arrival tomorrow

 

Cheers Lori. The solar fan is a great idea. I may have to start perusing around Amazon again

 

Hi Ricky101 its a single skin polythene all over the dome. fot the next on I build I am looking at using Polycarbonate, should be a much better job.

in a normal year we would only get a sprinkling of snow once or twice a year and maybe 10 light frosts max. just lots and lots of rain. I'll definitely look into the fan. Thanks