New or revised pages:
(latest at top)
1 December 2008
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House construction
Walls
Roofs
Doors
Windows
Heating
Air conditioning
Water
Hot water
Conclusions
Further reading
Most modern houses in Cyprus are not well
constructed from the point of view of the environment. Enormous amounts of
energy are needlessly wasted in both summer and winter, through cheap and
simple construction. The cost of improving this would be small, if the
necessary measures were taken at the time of construction. Modifying
existing houses would be expensive. Of course, the drama is a result of the
fact that no heating or air conditioning is required for most of the year,
but is required for short periods.
The use of water is also poorly managed in many
houses (see also the
essay on Water).
Again, conservation and recycling water would be cheap if this were foreseen
at the time of construction.
The following paragraphs apply essentially to
houses built before about 2004. More modern houses are built with a minimum,
but inadequate, amount of insulation.
Most houses are constructed with a reinforced
concrete skeleton to provide protection against earthquakes. The outside
walls are mostly filled in with terracotta bricks with air gaps. Both the
inside and outside surfaces are rendered with cement "plastering", to
provide a finish suitable for painting. There is no additional insulation.
The roofs are sometimes simply wooden joists
strung between members of the concrete skeleton, supporting wood planking
over which a waterproof layer is laid. Laths and then terracotta tiles are
fixed on top. Again, there is no insulation in many thousands of houses.
Outside doors are often in MDF and fit badly,
allowing air to circulate. In most cases, the front doors open directly into
the living room, without a porch or an intermediate hallway. This means
that, every time the door is opened in winter, heat escapes and, in summer,
heat enters, increasing the load on heating and air conditioning.
The case of windows is even worse.
Semi-reflective double glazing is fairly standard and should be effective.
The problem is that the frames and surrounds are in aluminium profiles,
which are excellent heat conductors. In the case of sliding double windows
and doors, there is a gap of several millimetres between the two window
frames. This is "closed" off by a thin brush or rubber flap, allowing an
important exchange of air with the outside. This is particularly noticeable
in winter when there is a strong wind blowing: cold draughts are inevitable.
Unfortunately, there is little alternative available. It would be possible
to have wooden-framed casement windows and doors, but the maintenance in the
climate would be difficult and expensive. All wood used for construction is
imported and expensive and not necessarily of the best quality. There could
be considerable shrinkage in the hot, dry summers and expansion in the cool,
wet winters. An annual painting would be necessary. More research into
synthetic constructional materials may be required to provide an answer to
this dilemma. UPVC may be a partial solution, but its longevity in this
climate has been put into doubt.
Even modern houses are constructed without
thought as to how they can be heated in winter. Because of the poor quality
of construction, some form of heating is necessary. All new houses should
have correctly insulated central heating pipework installed or three-phase
wiring for low-cost storage heaters. This lack of heating infrastructure
means that many kinds of wasteful, expensive and often polluting means are
used to ensure a reasonable degree of comfort. These include using
reversible air conditioning units, bottled gas radiant heaters, kerosene
heaters, electric convection or fan heaters and others.
Because of the poor insulation, the cost of
heating is at least twice what it should be with just a reasonable amount of
insulation and thought. The cost of this could be recovered easily in only
two or three winters.
Another problem is that, in cases where
oil-fired central heating is installed, the boiler, which also provides hot
water when the solar heating is inadequate, is often sited in an outhouse.
This means runs of outside poorly insulated pipework. When new, this is not
too catastrophic, but the quality of the insulation often deteriorates in
time, allowing the ingress of ground water. This may be very good for the
garden plants but is not good for the fuel bills. The idea of having the
boiler in a cellar under the house itself is rare, but offers other
advantages besides short, indoor, pipe runs. The fact that there is a
concrete slab between the boiler room and the house means that any waste
heat will help keep the house warm. Similarly, the heat from the chimney
pipe, usually embedded in the wall, also helps to keep the house warm.
While on the subject of oil-fired central
heating, there are rarely adequate precautions taken to prevent an
accidental leak of the heating oil from polluting the surrounding soil. It
should not be thought that either plastic or metallic tanks last
indefinitely and leaks can and do occur. Every tank should be situated in a
suitably lined brick housing that can contain the full volume of the tank,
in the event of a leak. It is probable that this is also required under EU
regulations.
Little emphasis has been placed on heat pump
heating. A properly designed system can be more energy-efficient than any
other. In some cases, the compressor can double as a chiller to provide
air-conditioning.
With modern houses, air conditioning is a must
for reasonable comfort in high summer. Central air-conditioning with a
chiller is not usually appropriate for individual houses, although they are
efficient for large apartment blocks. Split air-conditioning units are
suitable for villas and they should be dimensioned appropriately for each
room. Reversible systems can be used to provide emergency heat in winter at
no extra capital cost and minimal running costs. Suitable insulation,
as described in the previous section on construction will reduce energy
requirements, costs and pollution.
Unfortunately, air conditioning is abused by
many users, causing unnecessary energy consumption and consequent pollution.
My personal experience is that setting the temperature to about 27° or 28°C
provides all the comfort that is required, when dressed in summer clothes.
If the house is reasonably insulated, it can be switched off after about one
hour and the room will remain comfortable for quite long periods, even with
the outside temperature in the 40s. Of course, the "aircon" should be
switched off in rooms that will not be used in the near future. I find that
switching it on in bedrooms about 45 minutes before retiring and switching
it off again on going to bed will allow one to fall asleep in comfort and
there will be no disturbing noise. On awaking some six to eight hours later,
one is naturally uncomfortably hot but a good night's sleep has been
achieved at no energy cost. It is a mistake to run the bedroom units
throughout the night and it is not healthy. (If one awakes prematurely, for
example with the need to use the toilet, it may be necessary to switch it on
again, in hot weather, for 10 or 15 minutes, before settling down to
sleep again.)
These recommendations for usage may be
modified, of course, under individual conditions, particularly in the case
where someone is ill.
Domestic water management is atrociously poor
in a country where periodic droughts lead to severe water rationing. Low
volume toilet flushes are rare, the use of grey water for toilet flushing
and garden irrigation is almost unknown, collecting roof run-off for garden
irrigation or as a complement to grey water systems is equally rare. Yet the
cost of adding these to a new house is small and can reduce the water
consumption by half. Unfortunately, the cost of adding these to existing
houses is prohibitive, except possibly for a complete refurbishment.
Another negative is that the usual gravity-fed
hot water system often requires running water for minutes before it starts
to run hot. This cold water is usually allowed to run to waste. Ideally, a
pumped recirculatory hot water system would offer the comfort of instant hot
water in all taps and prevent this wastage, especially in houses without a
grey water system. The negative aspect is that the small pump does consume a
small quantity of electricity. This can be partially offset by using a timer
to run the pump only for a short period before expected periods of hot water
consumption (e.g., in the early morning for showers, at meal times for
washing up, in the evening for kid's baths etc.). At other times, the hot
water would still be available after a minute or so. In this case, the cold
water may be collected in a watering can for pot plants. Again, the extra
cost of adding a recirculatory system is almost negligible in new houses,
but is not too costly for existing houses, either.
Most houses up to an altitude of about 500 -
600 m are equipped with direct solar heating panels, which will provide
adequate hot water for most of the year. The payback time of these is
typically two to three years. In the high mountains, where severe frosts can
occur, a more expensive indirect solar water heater system is suitable, with
a payback time of eight to ten years. Ideally, the solar panels should be
complemented by an electric immersion heater for the few insufficiently
sunny days in winter. This is the most energy-efficient method. The
efficiency of using central heating water to heat domestic water is much
poorer and results in increased pollution, including greenhouse gas
emissions.
New houses in Cyprus can be made much more
energy-efficient at relatively little extra cost. No matter how heating and
air-conditioning is done, this reduction of energy requirements translates
into reduced running costs and reduced pollution. It is essential to
remember that increased energy usage engenders increased pollution, even if
that pollution comes from the stack of a power station hundreds of
kilometres away.
Where feasible, additional insulation can be
added to existing houses, especially when going through major redecoration
or refurbishment.
A major problem exists with modern window
construction. The aluminium frames, surrounds and runners, as well as
aluminium doors, are major causes of heat transmission between the inside
and outside of many houses. Without doubt, these extruded profiles are
excellent in every other way, but they probably cause 20 per cent or more of
the total losses from heating and cooling and thus an equivalent amount of
emitted pollution. It is suggested that some better form of window frame be
developed that would reduce these losses.
Architects and building contractors, heating
and sanitary engineers, as well as others involved with house construction,
should voluntarily suggest to their clients the benefits in building houses
with proper thought to reducing energy and water requirements. In the
meanwhile, general building standards can be improved while awaiting the
mandatory implementation of better means to achieve these results.
Green
Households
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