HOTHOUSE: Hot water provision in homes: Consumption, Storage and Lifestyle

We are compelled to move towards a low carbon future through government directives and legislation necessary to combat climate change. Simultaneously the nation must maintain a secure energy supply. The generation and consumption of energy for space heating and hot water provision in homes is a significant proportion of national energy use. As we reduce the need for space heating through increased efficiency, reduce the volumes that are heated in buildings, and become satisfied with lower internal temperatures, energy consumption for hot water provision will become more significant. The significance of hot water consumption in the future will also increase through pressures on the potable water supply to homes: in the UK water is heated potable (mains) water. The pressure on the nation's water and energy resources will increase as our population grows.

Our lifestyles and routines, however, do not always move in the right direction. The introduction of high efficiency condensing combination boilers, which are less wasteful than older boilers, has given access to 'unlimited' hot water supply, rather than consumption moderated by having a finite volume cylinder of water. This has led to the installation of larger shower heads, which use more water and longer showers, and hence the boiler efficiency savings are all but lost by increased consumption.

Trends like this are unintended and counter intuitive. Further complicating hot water use in the future, will be: the introduction of new heat generation and storage technologies, which might be all electric; the increasing intermittency of the supply of energy (affecting cost to the consumer); the potential for small-scale generation in the home; as well as the development of new appliances and services. Making decisions about how to provide hot water in the home is important. Poor decisions could mean that we use new technology inefficiently, because it doesn't operate in the way we need to meet our lifestyles. Alternatively, established household routines may need to change, in response to the features of new systems. This too could have undesirable, and unintended effects, such as increasing both water and energy consumption.

This project aims to understand what the likely future for hot water production in family homes looks like now, and as we transition to a new future. The HOTHOUSE project will consider such matters as new technology, appliances, hygiene routines (bathing and cleaning), energy efficiency, etc.

The research will:

* Develop future scenarios that describe these possible futures;
* Use numerical modelling to understand how the new technologies will perform in the home of the future; and,
* Evaluate the potential 'stresses' that might become acute as we try to reconcile our need for hot water and the pressures on supply.

The project is very timely and is supported by a range of organisations and businesses: EON (global energy provider); ETi (renovating smart heating systems for the UK); EST (energy saving advice for the consumer); PS Sustainability (design and build new low carbon homes); Bentley (a global modelling and simulation tools developer); BRE (a national centre for building an energy research); and Forum for the Future (Promotes sustainable thinking in organisations).

The work should generate new insights, data and modelling tools that will help many sectors of society from central government, through house builders and home energy equipment manufacturers, to the public that own or manage homes.

The scale of national challenge to deliver space heating and hot water demand under increasingly unpredictable supply cannot be under estimated. This proposal addresses the issue of hot water provision in homes where it is widely recognised that there is a lack in information and understanding across many stakeholder groups. The range of partners supporting this proposal, and the enthusiasm for the work that they express, illustrates both the need for the work and the breadth of the impacts that can be expected from the HOTHOUSE project. There are however many more potential beneficiaries from this work.

Policy makers are under pressure to evolve a low carbon energy system whilst maintaining a reliable energy supply which offers a hot water service provision comparable to that which households currently enjoy. This project will enable the energy supply implications of different water heating technologies to be understood, provide insights into the technologies most likely to emerge in a future energy system, and information about which technologies are likely to be deployed in grid and non-grid connected homes of different size and household composition. This information, together with the technologies' estimated energy demands, is a valuable input to national energy supply and demand models.

Energy supply companies will better gain insights into the energy demand for hot water and its co-incidence with demand for space heating and also the potential that different hot water heating technologies offer for load shifting. These matters influence the time-of-use tariff structures that may emerge in a future energy supply system. The work will also enable better estimation of the firm and despatchable supply capacity needed for hot water provision. Energy companies also operate models so will benefit from improvements in these (see below).

Home energy equipment manufacturers and installers will benefit from much better information about: the energy and efficiency of different hot water systems; the need for, and/or benefits of, storage; the necessary size of heating and thermal storage components to satisfy the demands of different households; and the requirements of controls, especially for remote demand-side management. Such information will help to inform their future systems development strategies, identifying the systems more or less likely to be attractive to each sector of the market.

Regulators are increasingly interested in standards and guidelines that act to regulate energy use and CO2 emissions from fixed services equipment (e.g. Building Regulations part L). The research will provide information to help frame future documents.

Consultants, designers and house builders: will be equipped with new models of hot water demand, using which they can design more effective systems and understand the space needs, and equipment and energy cost implications, of different options. The new hot water models will also extend the potential user base of the modelling systems within which they are embedded.

Urban planners could benefit from the new heating systems energy demand prediction tools to design local energy networks as a component of a 'smart city', or 'smarter' urban area.

Ultimately, the public that will live in, own, rent or let the homes of the future will ultimately have the most appropriate and cost effective hot water system.