Natural ventilation is gaining more attention from architects and engineers as an alternative way of cooling and ventilating indoor spaces. Based on building types, it could save between 13 and 40% of the building cooling energy use. However, this needs to be implemented and operated with a well-designed and integrated control system to avoid triggering discomfort for occupants. This paper seeks to review, discuss, and contribute to existing knowledge on the application of control systems and optimisation theories of naturally ventilated buildings to produce the best performance. The study finally presents an outstanding theoretical context and practical implementation for researchers seeking to explore the use of intelligent controls for optimal output in the pursuit to help solve intricate control problems in the building industry and suggests advanced control systems such as fuzzy logic control as an effective control strategy for an integrated control of ventilation, heating and cooling systems.

The US Better Buildings Neighborhood Program (BBNP) consisted of 41 different versions of thermal retrofit programmes with a common structure and objectives. This created a natural experiment in thermal retrofit programme design. This paper uses qualitative interviews with programme organizers measured against third-party programme performance data to create a model of 14 programme steps that were common to all BBNP grantees. This model uses the experiences of programme organizers to define best-practice principles associated with each programme step. Five themes emerge from the programme steps: (1) programme design: local market features and suitable programme structures; (2) marketing and outreach: the processes of creating awareness versus personal engagement – how community-based social marketing is a key strategy in driving demand; (3) workforce engagement: the skills gaps across the supply chain; (4) financial incentives: the merits of grants versus loans – how to use them in combination; and (5) data and evaluation: best-practice techniques for both programme evaluation and enabling iterative programme adjustments. These principles create a template for an ‘optimal’ programme model for retrofit programmes with stated objectives similar to the US BBNP. The potential and limitations in extrapolating this model to UK retrofit markets are considered.

How can programme design and strategy drive the decision actually to undertake retrofit upgrades? The US Better Buildings Neighborhood Program (BBNP) and the UK Green Deal both represent ambitious efforts to drive domestic retrofit markets. These programmes are compared and the differences in their conversion rates explored in the context of marketing, outreach and workforce engagement strategies. The impact of financial incentives is also explored. This paper supports the consensus that the US BBNP was successful against most of its stated objectives. The UK Green Deal, while slow to start, was gaining momentum before it was effectively ended. Semi-structured interviews with programme organizers give evidence that the Green Deal would have benefited from a more active approach to marketing and outreach, specifically emphasizing the distinction between the two. Marketing generates interest, but local outreach through word of mouth and personal referrals is needed to drive upgrades. The Green Deal did not sufficiently engage the workforce through an ongoing communication strategy and should have better facilitated both technical and non-technical skills development. The interest rate of the Green Deal is shown to be but one factor influencing participation, and can be effectively balanced through programme design in other areas.