Need advice? get in touch here. Contact us today for more information on our services and our coupon offers we serve all of south east pennsylvania with trucks in your area waiting for your call. Your flow rate multiplied by 3.5 gives you a rough idea of how powerful a boiler you’ll need in kilowatts, assuming your cold water comes in at about 10c your installer will be able to check your temperature and flow rate and help you make an accurate assessment. All estimates are free and flexible.