The decision to retrofit or replace your boiler is one you’ll be living with for some time. The service life of gas-fired boilers is long and component failures are generally uncommon. Energy efficiency is often the driving force behind the decision. Boiler efficiency is rated by its AFUE (annual fuel utilization efficiency) percentage. The number expresses the percentage of fuel that is actually used to create usable heat as opposed to heat that is lost during combustion. Older boilers came standard with AFUE ratings of 83 percent or less. A high-efficiency boiler will deliver an AFUE as high as 97 percent.
The best outcome for a boiler approaching the end of its service life with a low AFUE is probably replacement. A high-efficiency unit will begin reducing heating costs from day one. It will also be more environmentally sound and offer a longer warranty. However, a high-efficiency unit comes with a higher upfront purchase price, as well. Homeowners in climates with longer heating seasons have the best chance of achieving payback in a meaningful time span.
Another option for an older boiler is to retrofit the existing unit with more modern technology. Some of the retrofit options include:
- Intermittent ignition devices replace the traditional standing pilot light with an electronic igniter. This saves gas consumption from running the pilot light. However, on a small boiler, greater savings may be achieved by simply shutting down the pilot light seasonally.
- Modulating aquastats vary the heat of the water in the boiler according to the heating load on the home. Instead of keeping the temperature a continuous 185 degrees, a modulating aquastat lowers it to match the heating load, saving up to 10 percent of fuel costs.
- A time delay relay responds to the thermostat signal by circulating residual hot water into the system first before firing up the boiler. This short time delay in igniting the burner saves another 10 percent in fuel costs.
Through all seasons, Comfort Systemskeeps Wichita homes comfortable with the best in heating/cooling sales and service. Call us for more advice about options when its time to replace your boiler.
Our goal is to help educate our customers in Wichita, Kansas about energy and home comfort issues (specific to HVAC systems). For more information about boilers and other HVAC topics, download our free Home Comfort Resource guide.