large thermal comfort survey conducted using 1520
Thai volunteers from the three climatic regions of Thailand
and different types of air-conditioned buildings
from private and public sectors enabled to point out that
comfortable thermal conditions for Thais are quite different
from those widely used. The main results derived
from this study were as follows:
• The highest mean indoor temperature for thermal
acceptability of the subjects were 26C, 27.4 C and
26.4 C for zone H1, H2 and H3 respectively (see Fig.
1). The recommended nationwide indoor setpoint for
air-conditioning for buildings in Thailand is 26C,
which was accepted by most subjects in every climatic
zone (80% of votes).
• Because there was no humidity control for the
rooms relative humidity in air-conditioned rooms we
surveyed were different although the room temperatures
were the same. However, it was found that high relative
humidity effects the thermal sensation of the occupants
only when indoor temperature was relatively high
(around 26–27C). The surveys from the different zones
concluded that the appropriate relative humidity range
should be between 50% and 60%.
• Although many subjects surveyed preferred room
temperature to be set around 26C, the air-conditioned
rooms measured were set at lower temperatures as indicated
by negative mean comfort votes as shown in Fig.
4.
• The result of this study pointed out that non-quantifiable
factors could effect thermal comfort sensation
considerably. The acclimatization to using home airconditioners
termed as ‘‘AC acclimatization behavior’’
and high educational level. Both these factors make
the subjects preferred a somewhat lower comfort temperature,
and an average of about difference of 1C
was observed.
• Comparison with previous results on free running
buildings permitted us to validate the idea we introduced
previously on the possibility of extrapolation thermal
comfort standards for AC buildings from empirical evidence
from free running buildings in a fundamentally
different context. Although validated, however, we
acknowledge that our idea needs further investigation
and extensive discussion to determine an appropriate
methodology.
Although there used to be some energy conservation
campaigns launched by various governmental organizations
since 1992, such as the use of efficient air-conditioners,
insulation, fluorescent lamps etc., most of the
campaigns were not successful as energy consumption
has continued to increase steadily. There are many possible
reasons for this including people misunderstanding
and getting poor co-operation from the occupants of
the buildings, etc. In the Bangkok area during wintertime,
the outdoor temperature is often in the comfortable
range. Even so, most people in Bangkok like to switch on
the air-conditioners. One other reason for this was that
people wore clothes, which are not suitable for hot regions
like Thailand. These effects reflect some negligence,
misbehavior and irresponsibility among some people.
The result of this research has been transmitted to the
involved government agencies for implementation with
the coming new standards and regulations for buildings
in Thailand. We do strongly believe that the proposed
temperature set-point standard is not only a simple
way to reduce energy consumption of air-conditioning
system, as no investment is required, but the most effective
large scale energy saving method under Thailand climatic
conditions