15 ways to increase boiler efficiency：
 

1. increase boiler efficiency: lower the stack temperature

2. install an economizer

3. tune the burner regularly

4. install a variable frequency drive

5. increase boiler efficiency: insulate your valves

6. clean the fireside

7. preheat combustion air

8. clean the water side

9. return condensate to the boiler

10. recover heat from boiler blowdown

11. control blowdown rate

12. reduce excess air

13. reduce carry-over

14. survey steam traps

15. reduce steam usage