For Gary Sidelinger, the inspiration came when one of his old oil boilers went kaput.
An independent rental owner with 225 units in the Portland, Maine, area, Sidelinger hired an energy consultant to see if he could qualify for state efficiency incentives while replacing the aging oil heating systems in several of his buildings. The consultant recommended a conversion that’s becoming increasingly common throughout the Northeast: From oil to propane.
Sidelinger decided to install new propane boilers in two of his apartment complexes, the Beach Street Apartments and Terra Apartments. The Beach Street Apartments, in Saco, Maine, included two 10-unit buildings with hydronic heating and oil-fired boilers that are 20-plus years old.
“The oil-fired units that were there were reaching the end of their life anyhow,” Sidelinger says. “There is no city gas available, so your choices are propane or oil.”
Switching to propane boilers appealed to him on multiple levels. “I liked the idea, among other things, that it was a direct-vent unit,” Sidelinger says. “You’re pulling your combustion air from outdoors and then venting outdoors. It prevents creating a vacuum in your building, which an oil furnace does because the burner’s sucking air out of the building.”
The propane boiler would also provide significant energy savings, an important factor since Sidelinger is the one paying for the buildings’ heat. High-efficiency boilers would save him about $2,500 annually in energy costs for the two buildings, according to the consultant. The overall project, which included new circulators for the hydronic heating and other efficiency measures to tighten the envelopes of the buildings, would cost $24,120 and pay back more than $9,600 annually in energy savings.
“If you have a forced hot water [hydronic heating] system, it’s definitely worthwhile to look into propane.”
The two Buderus 93-percent-efficient, wall-hung propane boilers that were installed in the buildings had a number of other operational and efficiency benefits, notes Steve Trudelle, an energy advisor for Downeast Energy who coordinated the boiler installation. (Downeast also supplies propane to the buildings.) The Beach Street Apartments’ old oil boilers were not only oversized, but they also fired at full throttle no matter how much heat was needed. It wasn’t an efficient setup for the apartments, which each had separate thermostats, creating 10 separate zones.
“With one zone calling, it was firing close to 250,000 Btu to satisfy that one zone,” Trudelle says. The new boilers can modulate their propane output to a much lower level if fewer Btu are needed. The boilers are not temperature maintaining — they don’t have to keep a vessel of water heated 24 hours a day — and they use outdoor temperature reset controls, which adjust the boiler water temperature based on how cold it is outside. That way, the boiler can keep heating costs down even if a resident has their thermostat cranked up on a 50-degree day.
And because Sidelinger was upgrading the efficiency of his buildings by at least 20 percent, he was eligible for incentives from Efficiency Maine’s Multifamily Efficiency Program. Those incentives helped Sidelinger offset the installation cost and spurred him to investigate similar upgrades in other apartment buildings he owned. He ended up converting to propane boilers in the Terra Apartments, a 16-unit townhouse complex in Portland, as well, even though the oil boiler there was less than 10 years old. The cleanliness of propane, the advanced features of the propane boilers, and the possibility of converting to natural gas if it becomes available all contributed to that decision.
“If you have a forced hot water [hydronic heating] system, it’s definitely worthwhile to look into propane,” Sidelinger says. “You’re just changing your heat source and tying into your forced hot water system, so it’s a pretty straightforward, easy conversion.”
To learn more about oil-to-propane conversions, check out our two-part video that walks you through the steps of converting an oil-fueled boiler system to one based on high-efficiency propane.