Allotment Gardening Advice Help Chat

Growing => Growing in Greenhouses & Polytunnels => Topic started by: Bernard on July 29, 2015, 21:52

Title: Small heaters
Post by: Bernard on July 29, 2015, 21:52

I have used a small electric blower in my greenhouse for a couple of years but I find it is not a simple solution.

1. The low power setting (1kw) is no use. There is a danger that it will stay on most of the night but never reach the desired temperature. The 2kw setting is more reliable and economical.

2. The on/off range of the thermostat is far too wide.

3. In spite of circulation, the temperature is much higher at the roof than ground level. If the heater is near the floor, it does not switch off until the warm air reaches sown to it. I have raise it to 2 feet from the floor but angled it downwards. This causes it to respond more quickly and give a more even temperature on the vertical scale.

4. At any setting of the thermostat control, the temperature that will be acheived varies with ambient. In other words if the weather gets colder the control will have to be set higher .

I wonder if anyone else finds these problems?

incidentally, I have found that temperature in the greenhouse will fall quickly to 2 degrees lower than ambient if the night sky is clear, due to radiation. (I.e. without the heater)

Title: Re: Small heaters
Post by: yorky on July 30, 2015, 19:30

The answer is to use an external thermostat like this one,

http://www.twowests.co.uk/product/thermo-2-bio-green-digital-winter-summer-and-thermostat

I have used one for a few years now along with good bubble insulation and it is worth every penny of the initial cost. If you shop around you might be able to find one cheaper than the one in the link.

Title: Re: Small heaters
Post by: Bernard on July 31, 2015, 13:37

Thanks Yorky, good idea.