Boiler technology has come a long way in the past 15 to 25 years.
As an experienced construction pro, you may think it’s obvious. But when homeowners come to you needing to replace their old heating oil boilers, they may simply replace them with similar units, not realizing that there are more efficient options available. So it’s a point that plumbers, heating professionals, and remodelers must emphasize to help their customers make a smart decision for their replacement heating: Converting to a propane or natural gas boiler can greatly improve the efficiency of their heating system.
Matthew Freeman, product manager for Bosch and Buderus boilers, has worked in just about every branch of the home heating industry, first as a plumber, then as a wholesaler, and now for a boiler manufacturer. He says that while there is plenty of buzz around oil-to-gas boiler conversions, customers without access to natural gas may not know they can still upgrade with propane.
“I feel like they think they’re just stuck with oil,” he says.
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But by switching to propane, Freeman points out, homeowners can open up a new world of efficient heating. While oil boilers are generally limited to efficiency levels of 85 to 87 percent annual fuel utilization efficiency (AFUE), propane and gas units generally operate at 92 to 96 percent efficiency. “You don’t typically find a standard-efficiency propane unit,” he says. “Most propane units are high-efficiency units, whether it’s a furnace or a boiler.”
The difference lies in two technological features common in high-efficiency propane and gas boilers: They’re condensing and modulating. Condensing means they extract additional heat that would normally be lost through waste gases. The heat is extracted through a heat exchanger, which cools the gases, turning them into condensate.
But while condensing technology allows boilers to achieve efficiency levels in the mid-90s, modulating technology is what truly sets modern propane and gas boilers apart, Freeman says. A standard oil boiler has essentially one speed: It will heat to its maximum temperature of around 180 degrees, whether or not that level of heat is needed.
Modulating, condensing propane boilers can modulate their supply water temperature anywhere from 100 degrees to 180 degrees based on the level of heat needed within the home. “If they can meet the supply target of the room at 160 degrees, they will never run to 180 degrees if the thermostat is satisfied,” Freeman explains. “That’s how you’re saving energy.”
Smart control systems known as outdoor reset controls monitor the outdoor temperature and modulate the boiler’s supply temperature accordingly. Bosch is also developing a new Zone Control System package that will calculate the lowest possible supply temperature based on the current room temperature and the outdoor temperature, Freeman says. These features will boost the efficiency of a condensing boiler, which condenses more at lower supply temperatures.
The effect of these features on both heating costs and carbon emissions can be significant. Check out our Energy Cost and Carbon Calculator and enter details about your current heating system and energy costs to see how much you can save in your region.
In addition to reducing a homeowner’s fuel costs and emissions, condensing and modulating propane boilers can improve comfort, as well. Since oil boilers operate at only one speed, they often overshoot a home’s target temperature, and then allow it to swing several degrees below the target temperature before activating again. With smart controls, modulating boilers can provide steadier, more-even heat. “The ideal system would be getting a temperature that can heat the house, that’s not 180 degrees, and you feel comfortable with it all around the house,” Freeman says.
Converting a home’s fuel source from oil to propane may not be as complicated as you or your homeowner think. A propane boiler can be easily integrated into an existing oil heating delivery system, so the time and initial cost of conversion can be significantly reduced. Propane and heating oil are both stored onsite, but only propane can be stored in a hidden underground tank. And unlike heating oil, propane can be used for other systems in your home, such as cooking, clothes drying, fireplaces, and standby power generation. Propane also won’t cause damage or contaminate groundwater the way oil can if it’s spilled.
Continue your education about heating oil conversion by taking the Propane Training Academy’s online course, “Heating Oil Conversion: Exploring Propane as a Viable Alternative Energy Source.” You’ll become an expert on converting homes to the superior performance of propane, and we’re adding an incentive to make it even sweeter. Complete the course by Dec. 1, 2014, and you’ll be entered into a drawing for a $500 gift card. Visit the Propane Training Academy to get started.