Energy efficiency in residential dwellings

One in every five UK households are currently in fuel poverty. Coupled with the fact that energy providers are continually raising their prices, this issue is becoming increasingly prominent; the basic necessity of keeping warm can no longer be taken for granted. It is estimated that a minimum of 5.5 million people within the UK are living in houses that are inadequately heated

Source: www.eco-uk.co.uk

Fuel poverty occurs when a household spends 10% or more of its income on fuel; figures show that one in every five UK households are currently in fuel poverty. Coupled with the fact that energy providers are continually raising their prices, this issue is becoming increasingly prominent; the basic necessity of keeping warm can no longer be taken for granted. It is estimated that a minimum of 5.5 million people within the UK are living in houses that are inadequately heated due to self-rationing, made necessary by insufficient funds (The Guardian 2011). Modern new build properties benefit from legislation such as Part L of the Building Regulations, which ensure that construction is adequately insulated. Efficient methods of heating property are also being implemented more regularly; this however, provides no relief for the millions of people living within existing housing stock. 

While there are ways in which home-owners can improve thermal efficiency, methods often require financial investment (sometimes substantial), and exhibit long payback periods. Improving thermal efficiency, using external wall insulation for example, can result in payback periods of 12 years and cost as much as £65 per square metre (Oxford Solar n.d.). This can mean that while people may want to improve their homes, the same financial concerns which mean they are subjected to cold living conditions, prevent steps being taken to make improvements.  In addition to financial benefits, increasing efficiency will also result in fewer carbon emissions. The Climate Change Act 2008 has made the UK the only Country which has introduced a legally binding framework intended to address climate change by reducing emissions by at least 80% by 2050, when compared to the levels seen in 1990 (Committee on Climate Change n.d). Ensuring that existing homes are used efficiently is a cost effective way of contributing towards this target. The former coalition government saw Green Deal as a vehicle for meeting these targets; however Green Deal did not have the effect that the government had hoped. 

A Thermostatic Radiator Valve (TRV) - Source: abodesolutions.com

Daniel Coghlan, a recent graduate of mine at Coventry University, considered energy efficiency in residential dwellings as part of his final year dissertation, and undertook some very interesting research. The purpose of the research was to ascertain whether heating costs could be reduced by using an existing heating system more efficiently. If this was possible then this would allow savings to be made with little or no financial investment. The research involved taking meter readings in a selected residential property both before and after alterations were made to the use and set-up of the heating system. The usage during both periods was then compared to ascertain whether the alterations that were made have affected the efficiency of the central heating system, and if they have, to what extent.  The property selected was a detached 1970’s house with insulated cavity walls. The heating system comprised of a condensing combination boiler which fed a wet radiator array; heat was controlled using a programmer integral to the boiler, a central room thermostat and thermostatic radiator valves on each of the radiators.

A meter reading was taken on the 1st October 2011 and one was obtained from the resident for the 1st September 2011. The resident at the property was then left to utilise the heating system as they normally would; repeat readings were taken at the first of each month for a total period of 3 months, ending on 01st December 2012. The purpose of this was to ascertain energy usage over a set period of time prior to any system alterations. Following this, alterations were made to the system. These alterations included:

       1. Bleed radiators to remove trapped air
       2. Balance System
       3. Discuss room use and set TRVs accordingly
       4. Reduce temperature of system slightly
       5. Remove restrictions surrounding TRVs
       6. Set a programme timer suitable for general daily use
       
The results from the case study showed that alterations made to the set-up and use of the central heating system within the property resulted in a reduction of 18% in energy usage. It is understood that there were a number of limitations to the research, however this result  provides a strong indication that considered use can improve efficiency. In addition to the case study a questionnaire was devised to establish the levels of understanding of the use of a central heating system. Of the returned questionnaires, only 14% of those who responded used their central heating systems efficiently. Therefore, the combined result of the research shows that the efficiency of a central heating system can be improved by altering use, and currently, there is a deficiency in understanding or common practice of incorrect central heating system use within the UK.  

Limitations with the research were; 

Within the case study, monitoring was undertaken for three months in each period consecutively. This meant that varying weather conditions will have affected the boiler efficiency and the consequential energy consumption may not be completely representative of the alterations made. 

Another consideration is gas usage within the case study property as gas is not used exclusively for heating; the cooker hob is also fuelled using gas. This means that, while the same number of residents were residing within the property during both periods, varying eating patterns may have introduced further inaccuracy into the results. December for example is a time when residents are off work, and likely to entertain, again resulting in more cooking, higher gas usage and less reliable results. 

Different families are likely to have different comfort requirements and eating habits for example. In addition to this, differing windows, doors, thermal insulation, boiler type and radiator sizing for example would all make data obtained from different properties less directly comparable.  In addition there are a number of potential limitations commonly associated with observational information gathering techniques, such as when individuals or groups of individuals are aware they are being watched, they can sometimes change their behaviour, a phenomenon known as the Hawthorne effect (Kumar 2005: 120-121).

Despite these limitations the research demonstrated that energy and consequently cost savings can be made by educating and encouraging people to use their heating systems more efficiently.  Notwithstanding the fact that buildings also need to be made thermally efficient in the first instance, otherwise all of the heat created is likely to disappear through the walls.

(The above article is a summary of research undertaken by Daniel Coghlan BSc(Hons) as part of his final year dissertation at Coventry University and is published with the express permission of Daniel)

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