cost effectiveness

Multi-storey steel-and-glass office buildings suffer from a strong thermal load during the summertime, particularly in Mediterranean countries, and thermal discomfort is a very likely occurrence, even when a massive air conditioning centralized system is operated. Significant departures from thermal comfort conditions have been proven to result in decreased performance for office workers, which translates into a additional costs for the employer.

Radon gas is now considered to be a health hazard when found in excessive amounts in the builtenvironment. The levels of radon vary greatly, with some geographical areas having very highlevels. In the United Kingdom, Northamptonshire was declared an Affected Area in 1992, and itwas at this stage that our group first started studying radon levels and the steps taken to reducethem.The radon levels both before and after remediation were studied, together with the number ofoccupants of affected rooms, and their pattern of occupation.

The research was oriented to analyze better the ventilation systems, in terms of cost-to-quality ratio. The matter of the paper is that a ventilation system is designed to work in certain quality conditions, but every quality has its cost. This cost comprises investment, energy consumption and operation-maintenance expenditures.

Fresh air has a very important role in indoor air quality.This study aims at quantifying the costs and the gains of an increase of the ventilation rate, in an office building. Results show that a big increase of the ventilation rate leads to an increase of the installation costs, but to no change of the energy costs. The additional costs may be paid back quickly due to the productivity improvement.

The focus of this paper is on cost effectiveness of remedial measures for existing buildings in order to reduce high summer time indoor temperatures. A typical Finnish office building was selected for the analysis. The cost items included in the analysis are: the capital cost of the remedial measure (increase of ventilation, mechanical cooling added in central air handling unit), cost of the used energy (heat and electricity), and the cost of deteriorated productivity due to high temperatures.

Building environmental performance evaluation should make use of a life cycle assessment(LCA) approach, by considering all building process phases: raw material acquisition,manufacture, transportation, construction, use or operation, decommissioning, disposal andre-use. Such an approach is intended to measure, not only impacts on natural and non-naturalresources but also building indoor environmental quality (IEQ).

Life-cycle costs of investments for improving air quality in an office building were comparedwith the resulting revenues from increased office productivity; benefits from reduced healthcosts and sickness absence were not included. The building was simulated in a cold, amoderate and a hot climate. It was ventilated by a constant air volume system with heatrecovery. The air quality was improved by increasing the outdoor air supply rate and byreducing the pollution loads.

An investigation of the performance of a recently built estate of over 50 low-energy rental dwellings indicated that there was a slight but significant increase in electricity use of the “super low energy” designs over the control “low energy” designs. The “super low energy” designs included, in addition to the enhanced fabric specification of the “low-energy” types, active systems such as mechanical ventilation, solar DHW panels and enhanced space heating systems.