Electric Heating Systems

The most common way to heat a small glasshouse with low target temperatures is using electricity. Harrier GD offers two main types: Circulating Fan Heaters and Electric Tubular Heaters.

1) Circulating Fan Heaters

Fan Heaters This is the least expensive way of purchasing heat for your glasshouse.  If the structure is small (up to 15m2) and you don’t want to maintain a high temperature, one or two fan heaters could be the answer.  They have the added advantage that the heating element can be turned off in the summer and they can be used as a circulating fan.

2) Electric Tubular Heaters

Tubular heater

Tubular heaters can be positioned on the perimeter wall.

Installed in a duct.

… or installed in a duct.

As the glasshouse gets bigger (15 – 30 m2) or the temperature lift increases and demands heat inputs of 6 – 8kw, the more important it is that consideration is given to the way the heat is put into the glasshouse.  Electrical Tubular Heaters produce slow convected heat which will be the better option for uniform heat distribution, and will avoid dehydration of plants, which can be caused by fast moving air from fan heaters.  They are easierand cheaper to install than a typical Hot Water System, but are less economical to run in a larger greenhouse.

Specification

Placement

How many?

Other components

Contactor and thermostat  with tubular heater.

Contactor and thermostat with tubular heater.

A Thermostat is required to set the desired temperature.  Harrier GD uses a high quality weatherproof thermostat with an IP56 rating.

For installations using a larger number of Tubular Heaters, and /or when vent mechanisms are electrically controlled, we would recommend upgrading to an HH2 or HH3 Controller. Details of these can be found in ‘Hot Water Heating Systems’

A Contactor Box (Heavy duty switch) should be ordered with heaters.  It is connected to the control system, and has the capacity to run high power requirements of multiple tubular heater installations

Cost

All projects will be slightly different, so the following is only a guide.  If a customer required 4kw of heat they would need:

‘Supply Only’ cost for the above, including delivery would be £1770 + VAT (Nov 2013)

Customers should contact us to establish how many Tubular Heaters they need for the desired temperature lift in their glasshouse.  The Tubular Heaters can be sold as ‘Supply Only’ or can be ‘Installed’ by a Harrier GD fitter.