These are short surveys of existing buildings for owners who want help to cut their bills. There is often scope for large energy savings without major capital expenditure and with relatively high returns on investment.
Energy efficiency investments can be regarded as savings accounts which deliver a steady index-linked income. The typical return is better than from the ‘Feed In Tariff’.
The chart below shows a hypothetical office building which makes a 50% saving via relatively high-return measures. Modifications to the space or water heating systems, pumps and fans, more energy-efficient lighting and electrical equipment usually deliver the highest returns. Building insulation improvements can be worthwhile but often deliver lower returns than modifications to the services.
Lower Energy Costs and Reduced CO2 Emissions,
3,000 m2 Office Building.
NOTE: Circumstances vary. Typical case of a building retrofitted with low- and no-cost improvements to the heating and lighting systems and their controls, electrical office equipment, fans and pumps and limited thermal insulation.
Buildings surveyed have ranged from churches and village halls to offices, doctors’ surgeries and factories. The savings identified in short surveys usually range from about 25% to 50-60%, depending on the individual case.
The figure shows what might be achieved in a hypothetical medium-sized office building from measures with medium to high returns on investment, say over 10% per year.
The buildings below were surveyed for owners who were concerned at their high energy bills. The details and recommendations listed here can usually be established via a survey lasting less than two hours on small buildings of 300-500 m2. For buildings which are being constructed from new, or whose owners plan total refurbishment, see Building Projects.
2012 – Doctor’s surgery, small West Midlands city.
Suggestions how to reduce both the gas and electricity bills via measures with relatively high returns on investment. The areas highlighted for attention included an outdated gas heating system, poor system controls, a need for cavity wall insulation and a need for more energy-efficient lighting throughout the building.
2012 – Village hall and shop, rural West Midlands.
The buildings surveyed were constructed in 1999-2000 to Part L of the 1995 Building Regulations. The village has no natural gas.
Despite being on a ‘cheap’ electricity tariff, the hall was spending £4,000 per year on electricity. Users reported still being cold. The original electric underfloor heating had been abandoned due to high running costs, poor control and damage to the wooden floor by the heat from the buried wires. Portable electric convector heaters were being used for evening meetings. Although the lighting was fitted only 10-12 years ago, it was very inefficient.
The shop was spending £130 per month; i.e., over £1,500/year on electricity to operate two fresh food chiller cabinets and a soft drinks display case. Electricity was also consumed for air conditioning to remove the heat generated by the refrigeration plant.
Such chiller cabinets are widespread in the retail sector. Their energy efficiency varies but is far lower than that of domestic refrigerators.
Right – A classic ‘power guzzler’: a refrigerated display case for fresh food.
Represents just one of thousands of generic products made in the Far East or other low-cost manufacturing areas and sold worldwide.
The main recommendations on the village hall were to add a little further insulation and draughtproofing and change the heating system from off-peak electricity to a condensing boiler with effective controls. The lighting would be replaced by a mix of T5 lamps and CFLs or LEDs. Now, two years later, the suggestion would be LEDs and T5s.
The shop lighting was new and fairly energy-efficient, so not worth replacing. The main potential savings involved fitting more energy-efficient refrigerated cabinets and supplying the residual amount of air conditioning more efficiently. It should be possible to reduce electricity consumption for these uses by over 80% and make high returns on investment; i.e., a short payback time.
2012 – Doctor’s surgery, small West Midlands town.
Improvements were proposed to the walls, the pitched slate roof and the efficiency of electricity use in lighting and equipment, plus modernisation of a dated gas central heating system.
2012 – Community hall, urban West Midlands.
Outline recommendations for wall and roof insulation and improving the existing fluorescent lighting.
2013 – Methodist church and attached hall, conservation area in a West Midlands town.
Recommendations included replacing the gas heating system and carrying out solid wall, extra roof insulation and floor insulation as and when grants allow, plus work on the existing historic windows, plus more energy-efficient lighting.
It was advised that work on the heating and lighting systems should go ahead anyway. The returns on investment were higher than for retrofit insulation measures.
2015 – Detached cottage, south-west England.
This survey was carried out on a rural house which dates from the 18th or early 19th century. The original building is stone and solid-walled but it has three cavity-walled extensions dating from respectively the 1950s, the 1970s and the 1980s.The total floor area is 150 m2.
The owners spend £1,500 per year on heating oil. But they are still cold. They will have a lower income after they retire and are very worried that they may be unable to afford to heat it. They wanted to know whether the dwelling could be improved in energy efficiency, ideally reducing their bill to around a tenth of the present level and at a cost which would make economic sense to them after their retirment.
It was noted that some major items of building work had been undertaken by the previous owners without adding any energy efficiency measures. Low-cost opportunities to improve the levels of roof insulation and draughtproofing had been missed.
An oil condensing boiler had been fitted to the dwelling before the owners purchased it in 2012. But unfortunately, the work did not include the controls most suited to condensing boilers; i.e., weather compensation and related measures.
The owners were advised that some changes to the lighting should go ahead anyway, reducing electricity bills for this purpose by 50 to 80%. In addition, minor adjustments to the heating controls and improved tank and pipe insulation should be able to save of the order of 10-15% of the existing oil bill. These give acceptable returns on investment.
The ‘bottom line’, however, was that this dwelling contained construction details of great complexity. These issues contribute to the very high space heating bills and the occupants’ poor comfort. In the current situation, the dwelling could probably not be improved in order to yield an ‘affordable’ fuel bill for the owners’ retirement. At least, it could not be done for a cost which they would find acceptable. The owners were advised to consider other strategies to secure the desired end result.
The finding was much as the owners suspected but they greatly valued receiving an expert opinion on the subject. They had been ‘going round in circles’ with commercial organisations and stated that they never received consistent advice from two different companies.