This guide has been produced by Low Energy Supermarket to list common energy improvement recommendations as commonly found on Commercial Energy Performance Certificate Reports. These recommendations have been developed via the Carbon Trust and qualified energy assessors.
Not all of these improvements will be applicable to your property and some will vary dependant upon its construction. The energy efficiency recommendations below are intended as guidance only. For further detailed property specific advice or energy ratings can be prepared by a qualified energy assessor which can be found at the link below:- https://www.ndepcregister.com/searchAssessor.html
Improvements below within each category have been listed in order of payback time – shortest payback first.
Payback is the time it takes for the cost of the energy efficiency improvements to be paid back through your cheaper energy bill savings.
For short to medium payback improvements, do worry about throwing out lighting or old heating boilers which are working fine as their replacements will quickly pay for themselves through their energy saving efficiency.
- Change halogen spotlights to LED or CFL retrofit light bulbs Payback is generally less than 2 years but can be a low a 3 or 4 months.
- Change old incandescent light bulbs to CFL fluorescent energy saving or LED Light bulbs.
- Fit retrofit energy saving conversion kits to change tube lights from T12 to T5 fluorescent tubes which can reduce electricity consumption by 60%. T8 to T5 tube conversions give 45-50% energy savings.
- Replace high-pressure mercury discharge lamps with plug-in SON replacements.
- Install PIR or microwave lighting occupancy sensors to occasional usage areas such as store rooms, toilets, kitchens, corridors to automatically turn lighting off when not required. This generally has a two-year payback.
- Display lighting should be fitted with a timer to minimise lighting on time.
- Fit photoelectric day light zoning controls be fitted so that lighting close to the windows is automatically turned off when not required.
Voltage Optimisation and Power Factor Correction (PFC)
- Fit voltage optimisation equipment to reduce voltage to 220v, which can give 8-12% electricity savings.
- Fit Power factor correction to equipment with large inductive loads such as machinery or motorised equipment such as lifts. Seek further specialist advice.
Heating & Cooling
- Old heating boilers may only have 65% efficiency or less. A modern condensing boiler is capable of over 90-95% efficiency meaning it will burn less fuel to heat the building.
- If there is no gas supply, some larger buildings will be better suited to a high efficiency air source heat pump system such as a VRF multi-split air conditioning system, which would provide heating and summer cooling.
- Expensive electric heaters should never be used where a gas supply is available which could power an efficient condensing boiler.
- Consider switching from gas to biomass fuel.
- Smaller properties without gas should consider installing an air source heat pump available from around £500 each, which uses 3.5 – 4 times less electricity than electric panel, fanned or storage heaters. This will give significant improvement to energy efficiency. An air source heat pump or split system air conditioning can provide a complete heating and cooling solution. Look for high EER (cooling energy efficiency ratio) and COP (heating coefficient of performance) figures in purchasing specifications
- Add heat recovery to the ducted heating/cooling system. A heat recovery unit can recover up to 65% of the heat from the exhaust air without cross contamination of the intake/extract air supplies were required.
- Know the efficiency of your cooling systems. Some older air conditioning units have low efficiency. Some systems can have efficiency improvements such as changing the type of coolant.
- Ensure basic time control of you heating system.
- Large buildings may require local time control unless all heating is normally on at the same time.
- Each room should have thermostatic control valves or air con thermostat. Central circulation areas should also have wall thermostats.
- Best heating systems will be zoned for local time and heat control, especially important for larger buildings.
- Fit optimum start stop to ensure heating does not come on too early.
- Fit weather compensation controls.
- Fit variable speed controllers to heating circulation pumps. Payback can be as low and 10 months. Obtain further advice from a mechenical and electrical consultant.
- Fit metering provisions to the heating system with monitoring and targeting alarms for out or range values to aid energy management.
Hot Water Efficiency
- Hot water storage tanks and cylinders constantly loose heat which must be reduced by thick insulation. A small building with low hot water usage does not need a hot water storage cylinder. Removing hot water cylinders and secondary circulation and replacing the hot water system with instant electric hot water heaters above all sink/ wash hand basins can have a 30-40% higher efficiency than upgrading the insulation to hot water cylinders and secondary circulation. Where there is a higher demand for hot water, i.e. kitchens, local highly insulated electric immersion hot water storage cylinders can be fitted.
- Improve hot water cylinder insulation jacket to at least 80mm thick, preferably 120mm thick. Fit programmer timer switch to minimise hot water heating times.
- Where hot water is heated but central heating circulation from a main gas boiler, ensure a thermostat is fitted to the cylinder.
- Hot water pipes from the hot water cylinder should also be insulated, using pre-formed pipe insulation of up to 50 mm thickness, or to suit the space available.
- Large buildings will normally have a secondary hot water loop. Consider replacement of the secondary circulation pumps for the hot water with more efficient variable flow pumps. Also improve pipe insulation to secondary hot water circulation pipes to at least 25mm thick throughout the building. A timer should also be fitted to secondary hot water circulation so that the pump is not running continuously.
Building Fabric – Insulation
- Reduce air leakage through the fabric. Draught proof all windows and doors and seal all joints between construction elements. Redundant ventilation openings should also be sealed, reduce fan extraction rates or install heat recovery. Seal old chimney flues.
- Install or improve roof insulation. Roof insulation laid in the roof void above ceilings to a depth of at least 270mm will mean around 15-17 times less heat will be lost through the roof. Loose granules where access is difficult. Rigid polyurethane insulation boards to a thickness of at least 160mm can be used between/ beneath roof rafters where there are sloping ceilings. Maintain roof ventilation.
- Flat roof heat loss is high in many buildings with the likelihood of no insulation. Always use recovering as an opportunity to upgrade flat roof insulation. An un-insulated concrete flat roof will loose around twice as much heat as an un-insulated timber flat roof.
- Install injected cavity fill wall insulation. Short payback and very effective. Specialist installation widely available – get your free survey.
- Buildings with thin cavities may require injected insulation and internal or external insulation for effective heat loss reduction.
- Add insulation to solid external walls and party walls if unheated to the other side. Solid wall insulation involves adding a layer of insulation, normally 100mm thick to either the inside or the outside surface of the external walls.
- Install low-emissivity double-glazing in place of the current single glazing.
- If a property is within a conservation area it is unlikely that double-glazing will be allowed due to planning restrictions. It is recommended that a clear low-emissivity heat reflective film be installed to the windows, which can significantly improve their insulation value. This film can also be used for shop display windows.
- Double glazed windows installed before 2002 will not have the special heat reflective low-emissivity coating used on modern windows. It is recommended that a clear low-emmisivity film be installed to the windows, which can significantly improve their insulation value.
- Where floors are poorly insulated – introduce and/or improve insulation. Add insulation to the exposed surfaces of floors adjacent to underground, unheated spaces or exterior.
Air Conditioning Efficiency (where fitted)
- Reduce load on air conditioning systems by using solar reflective film to windows. Also consider bris soleil shading overhangs.
- Make use of/ install free cooling coils to reduce air con costs/energy usage, get further advice.
- Shading – effective use of blinds to reduce air con energy usage,
Mechanical Ventilation Systems (providing heating and cooling)
- Ductwork leakage is greater than 10%. Inspect and seal ductwork.
Warehousing Energy Improvements
- If a gas supply is available then gas powered radiant heating is much cheaper and efficient that electric radiant heating. Radiant heating is commonly used as it radiates heat making operatives feel warm rather than heating the air and warming the structure of the building like traditional heating which is less efficient.
- Consider fitting destratification fans where ceilings are more than 3-4 meters high to ensure the heated air is blown back down into the occupied space therefore avoiding excessive heat loss due to warmed air rising above occupier areas. This can reduce heating costs by 20%. It is recommended that these fans be thermostatically activated when they detect excessive high-level air temperatures.
Renewable Energy Sources
- Install a solar photovoltaic system. Feed in Tariffs (FITs) should be explored.
- Install a ground source heat pump (higher efficiency than air source heat pumps)
- Consider installing building mounted wind turbine(s). Feed in Tariffs (FITs) should be explored. Some areas more suitable than others. A specialist installer survey is recommended.
- Install solar water heating. A solar water heating panel, usually fixed to the roof, uses the sun to pre-heat the hot water supply which reduces demand on the heating system. Best situated to high hot water usage buildings.
- Combined heat and power can be more efficient than traditional systems but suitability needed to be carefully checked.