Energy Saving Fact Sheet Boilers

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1 Energy Saving Fact Sheet Boilers

2 Turn a burning issue into real energy savings You need a boiler to heat your premises and provide hot water or to generate steam for use in industrial processes. Unfortunately, boilers are often forgotten when looking for energy-saving opportunities. But you can make significant cost savings through effective operation and maintenance. This straightforward fact sheet will help you keep your boiler in peak condition. Energy wasting hot spots Want to know where you can start saving energy? This useful chart gives you a quick idea of the impact of simple low-cost measures, such as maintaining the boiler in good condition. How most businesses can save money and energy on boilers Operation and Maintenance Fact! Around 20% of heat generated by a boiler goes straight up the chimney. This can increase to over 30% if the boiler is poorly operated or maintained. More Complex Measures Energy Saving Fact Sheet Boilers Inspection Check your boilers regularly between services. These common signs of boiler inefficiency need immediate attention by your service engineer: Warning lights or smell of gas. A possible safety problem turn equipment off straight away. Leaks. These can come from water, heating and steam pipes, valves, flanges and worn linkages, as well as from boilers themselves. Damage. Look for burn marks and other physical evidence. Noise. Undue noise from pumps and burners can indicate poor combustion or wear. Controls. Poorly calibrated controls can affect combustion, so ensure that the settings are accurate by having them checked as part of your regular service. Maintenance Good fuel consumption and low chimney heat loss can help improve efficiency. Here s how to achieve it: Annual check-up. Get a qualified contractor to clean and service your boiler at least once a year to remove the build-up of deposits. The service should include a combustion efficiency check and adjustments to optimise the burner air-fuel ratio. Keep your eyes open. Measure the temperature and oxygen content of the flue gases and have your boiler cleaned when the maximum temperature of the gases rises more than 40ºC above that of the last service. If you don t have a flue gas thermometer, install one! Breathe easy. Your boiler needs an unrestricted air supply for complete combustion; so check for adequate ventilation, and that louvers and vents are open and clear.

3 Choosing a boiler There are many different types and sizes of boiler depending on the amount of heat or steam that needs to be generated. Conventional boilers usually use a header (or feeder) tank to supply cold water, and a hot water cylinder to store heated water. Although the design of these boilers has improved in recent years, they tend to be relatively inefficient compared with other types. In a combination boiler, water is fed directly into the boiler and heated 'on-demand by an efficient heat exchanger. Because hot water is produced only when it is needed, there is no need for a hot water storage cylinder, making combination or combi boilers much more efficient than conventional boilers. Condensing boilers are perhaps the most efficient boilers on the market. A heat exchanger in the flue is used to extract much of the heat that would otherwise be lost in the exhaust gas, and return it to the system. They can cost slightly more than other boilers but in situations where there is a reasonably high heat demand, the savings should outweigh the additional cost. Most of the steam boilers found in industry are similar in design to a traditional boiler but often incorporate systems such as steam trapping, which improves the quality and efficiency of the steam, and condensate return whereby moisture in the steam is re-used as pre-heated feed water. These systems can drastically improve the efficiency of the boiler and the efficiency of steam-powered processes. Operation Apart from switching off boilers when they re not needed, there s more you can do to save energy: Complete shut down. Did you realise that boilers sometimes continue to fire even when the room thermostat or time-switch shuts off the circulation pump? If this happens, your electrician may be able to alter the wiring so that the boiler shuts down too. Get smart. If you have several boilers, turn one or more them off during milder weather. Consider installing boiler sequencing controls; these ensure that the minimum number of boilers fires to meet demands and that they operate in the most efficient order such as the smallest first. Slow down. When you re using boilers to generate steam, try using the lowest possible steam pressure that your process allows it will reduce demand on the boiler. Pipework Once you ve generated heat, you ll want to make sure it gets to where it s needed as efficiently as possible: Keep it covered. Insulating pipework can reduce heat loss from pipes by over 70%. Make sure that all heating pipework is insulated. Cut it out. Check your system for unused pipework a major source of heat loss. If possible, remove redundant piping or isolate it using a valve. GIL151 How to fit pipework insulation will tell you more. Trap it. In steam systems, steam traps can reduce generation costs by up to 30% by returning unwanted condensate from the steam. Ask an independent expert to check your steam distribution to see if steam-trapping can be improved.

4 Know your boiler A boiler is very much like an engine the better the flow of air and fuel through the system, the more efficient the combustion. This is why maintenance is so important. Cleaning burners and flues, such as in the diagram below, lets the fuel burn efficiently, as well as increasing the life of the appliance. Major components in a typical gas hot-water boiler Exhaust Gases Draft Hood Water Feed Hot Water Outlet Temperature & Pressure Controls Circulating Pump Drain Insulated Metal Enclosure Heat Exchanger Gas Valve and Burner Controls Gas Inlet Gas Burners Helpline More complex measures There are further advanced actions that you can take to increase efficiency: Wrap it up. Uninsulated boilers lose heat into the surrounding area a significant waste of money. Consider fitting minimum 50mm thick fibre mat with foil laminate to the inside of the boiler. Blow it down. Blowdown is when some water is removed from the boiler to remove solid impurities. This protects boiler surfaces from severe scaling or corrosion problems, but also wastes hot water and should be kept to the minimum. Read our guide GPG369 Energy efficient operation of boilers for further guidance. Keep it clean. Keeping feed water as clean as possible will help reduce the build-up of scale and the need for blowdown. You can use chemicals that improve the water quality by reducing the amount of solids. Ask your boiler engineer to see whether this could help. Slow it down. Some larger boilers have fan-assisted flues. Often you can replace the conventional electric motors that power these fans with more efficient variable-speed drives. Your boiler engineer will to tell you whether you have a fan-assisted flue and identify the fan speed/load. Consult our guide GIL152 How to select a variable speed drive to assess whether a VSD will help save energy.

5 Take action! Start saving energy today Allocate responsibility to a member of staff or small team who can drive forward energy-saving measures: 1. Switch off. Make sure that your boilers are turned off when there s no demand for heat, especially when buildings are unoccupied in the evenings and at weekends. 2. Maintain. Good boiler maintenance is essential to ensure efficient combustion. Have your boiler serviced regularly. 3. Fix. Be sure to stop all leaks in water, heating and steam pipes. 4. Check steam pressure. If you use your boiler to generate steam, use the lowest possible steam pressure for your processes. 5. Get the guide. Call the Carbon Trust Energy Helpline for a copy of How to maintain your heating system our step-by-step guide to saving energy with your boiler. The Helpline can also give you additional energy-saving tips and advice for your business. Helpline Purchasing and upgrading If you re considering installing a new boiler, buy one on the approved Energy Technology List (at This details products that meet certain energy-efficiency criteria. You may also qualify for a valuable Enhanced Capital Allowance and an interest-free loan from the Carbon Trust. Call our Helpline for more information.

6 The Carbon Trust helps businesses and public sector organisations cut their energy costs to combat climate change through the provision of free, professional advice and assistance. Want to find out more? There are useful energy-saving guides at and through our Helpline FL177 Industrial boilers & heat distribution systems money to burn? GPG381 GPG369 GIL152 GIL151 GIL156 Energy efficient boilers and heat distribution systems: choosing the best for your site Energy efficient operation of boilers How to select a variable speed drive How to fit pipework insulation How to maintain your heating system You can access the Energy Technology List at We ve got many more tips on boilers that will help you save energy and money. So give our Helpline a call today. Helpline The Carbon Trust is funded by the Department for Environment, Food and Rural Affairs, the Scottish Executive, the Welsh Assembly Government and Invest Northern Ireland. Whilst we have taken reasonable steps to ensure that the information contained within this leaflet is correct, we give no warranty and make no representation as to its accuracy and we accept no liability for any errors or omissions and neither does the Government. The Carbon Trust is a company limited by guarantee. Registered in England and Wales Number Registered at: 8th Floor, 3 Clement s Inn, London WC2A 2AZ. Queen s Printer and Controller of HMSO, May 2005 Ref: GIL121