The responsibility for changing to a sustainable lifestyle
– one that meets the needs of the present while respecting the ability of future
generations to meet their needs, rests with each of us. Energy conservation is
central to living in a sustainable way and a great place to start is in the
greenhouse.
The air as it moves over glass is major cause of heat loss in
the greenhouse. It is therefore very important to site the greenhouse out of
cold winds. Be especially careful not to have it exposed to easterly or
northerly winds. Positioning the house to take full advantage of the winter
sunshine would go a long way to cutting heating costs. Double-glazing is very
expensive as the extra weight of glass requires a robust structure, but if you
are planning to have a warm greenhouse throughout the winter then it might be
worth the cost.
As winter approaches it is time to think of protecting the
plants in your greenhouse. If the costs of heating your greenhouse were rising
each year, maybe now would be a good time to consider providing a windbreak. If
your garden is in an exposed area, the greenhouse looses a considerable amount
of heat due to being exposed. A natural windbreak sited no closer than four
times the height of the greenhouse would be a great advantage in heat
conversation.
Types of heat:
Electric:
This is the most efficient and cleanest fuel available. It is
easy to maintain a specific temperature and so in terms of energy conservation
it is the best.
Gas, Paraffin:
As these fuels require some form of ventilation to avoid risk
of fume damage or fungal damage because of the production of vapour, the
resultant heat loss makes them less efficient.
All heating systems should be fitted with thermostatic
controls for the efficient use of heat.
New Greenhouse
Freestanding
structures with glass to the floor are subject to the largest amount of heat
loss. Structures mounted on a brick base or half-timbered at the sides have
less heat loss.
Lean-to greenhouses
require a lot less heating so is worth considering. If you can use a house
wall that is warm all the better.
Site the greenhouse
in the most sheltered part of the garden or provide shelter. Take particular
note of where the winter sun shines and take full advantage of it.
All greenhouse owners
should invest in a good maximum/ minimum thermometer and use it to monitor the
temperature changes and so adjust the heating quickly.
There is little to
choose between wood and aluminium but wood is perhaps easier to position in a
garden setting as it is a natural product.
Double walled
polycarbonate panels can be used; they are better than glass at conserving
heat. The downside of polycarbonate is the lower level of light transmission;
because of this it is not ideal for the strong plant growth.
Consider safety if
small children are likely to be running around near the greenhouse. Use safety
glass if you can. Otherwise cover the vulnerable panes of glass with a strong
wire frame.
The R.H.S.I would ask its members and the public to give
serious consideration to the conservation of energy. Use energy with
economy.
Insulating an existing Greenhouse.
Make sure that the panes are close fitting
and seal where necessary.
Lining the greenhouse
inside with bubble wrap can reduce the heat loss.
If you only have a few plants that need protection
make a mini greenhouse within the existing
house.
Watch out for condensation particularly if you are using gas or
paraffin heat. The problem is not as bad with electric heat.
Text prepard by Mary Waldron (R.H.S.I)
Further information contact the RHSI at: Swanbrook House,
Bloomfield Ave, Donnybrook, Dublin 4.
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