436 Energy Project Financing: Resources and Strategies for Success
sufficient moisture removal and excess indoor humidity. Condensation
of water vapor on radiant cooling panels is much more likely in high
humidity climates. Maintaining thermal comfort with natural ventila-
tion is much more difficult in warm humid climates.
In cold climates, thermally efficient windows, high levels of ther-
mal insulation in the building envelope, and measures that reduce air
infiltration are more likely to significantly improve thermal comfort by
reducing drafts and radiant heat losses from occupants to walls and
windows. The potential to have very low indoor humidities is also
increased in cold climates.
levated levels of pollutants in the outdoor airE ncrease certain i
IEQ risks. Energy conservation measures that increase outside air
supply, will generally improve IEQ by reducing concentrations of in-
door-generated air pollutants. However, when outdoor air quality is
poor, e.g., when outdoor pollutant concentrations exceed applicable
standards, these same energy conservation measures may increase the
indoor concentration of outdoor pollutants.
haracteristics of the building and building HVAC systemC lso in-a
fluence the IEQ outcomes from energy conservation. Only a few of the
many possible interactions are described here. The magnitude of indoor
pollutant emission rates is one consideration. If the building contains
strong indoor sources of air pollutants, energy conservation measures
that reduce outside air supply are much more likely to result in elevated
concentrations of these indoor-generated pollutants. (The converse is also
true.) Similarly, if a building has a low rate of outside air supply, pol-
lutants emitted from energy conservation products such as sealants are
more likely to significantly degrade indoor air quality. Energy conserva-
tion measures that reduce outside air ventilation are more likely to lead
to IEQ problems if the initial rate of outside air supply is low.
roper implementation of the energy conservation measures P can
prevent many of the potential adverse impacts on IEQ. Most of the pos-
sible implementation errors are obvious: faulty design, installation, cali-
brations, control methods, commissioning, operation, or maintenance of
the energy conservation systems or practices can lead to IEQ problems.
Proper design, training of users, etc. can prevent problems.
ngineering calculations and computer modeling E are the primary
tools for predicting levels of IEQ or the magnitude of changes in IEQ.
Indoor temperatures are determined from energy balances, and indoor
humidity and pollutant concentrations from mass balances. Algorithms