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Q&A Spotlight

Options for Replacing a Boiler

Is an air-to-water heat pump a drop-in replacement for an oil boiler?

An oil-fired cast-iron boiler is typically a reliable and long-lasting heating appliance, but an early failure has a homeowner wondering whether he should transition to something else, such as an air-to-water heat pump. Is the strategy sound? Maybe not. Photo credit: Alex Wilson.

After just 20 months, Ineffable’s oil-fired boiler has failed and the labor estimate to repair it under warranty is twice what it originally cost to install it. “In light of how awful my experience with the boiler has been,” he writes in this recent Q&A post, “I am looking at other options.”

At the top of his list is an air-to-water heat pump that could become a drop-in replacement—assuming that such a product would work in his situation.

Ineffable lives in a 1900-sq.-ft. home in central Connecticut, where he estimates the maximum heating load is about 75,000 Btu per hour. Even on cold days, the boiler ran no more than 30% of the time.

“There is no natural gas available,” he explains, “and I cannot run ductwork, install minisplits, or install radiant floors (house construction is unusual). Baseboard and valance heaters can be added or replaced with higher output if needed.”

What are Ineffable’s best options? That’s the question for this Q&A Spotlight.

First, what’s up with the boiler?

Paul Wiedefeld, among others, is shocked that the boiler—which Ineffable says is a Buderus G115/WS3—stopped working after less than two years in service.

“Did you get a second opinion?” asks Walter Ahlgrim. “Did you contact the manufacturer? In general, boilers tend to have a longer service life than other types of equipment. It would be interesting to know why yours failed.”

Ineffable says that a seal between boiler sections began to leak, allowing a pool of water to accumulate in the combustion chamber. That prevented the burner from running properly. “Basically, it was a manufacturing defect,” he says.

According to Ineffable, Buderus will replace the block for a $200 processing fee, but installation of the block would take an estimated four…

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  1. iainb | | #1

    I have a quick question about the Dana Dorsett column. I was attempting to use that myself to determine my heating stats but my boiler was an oil burner converted to natural gas.

    Is there a way to figure out the efficiency of a boiler that's had a fuel conversion?

  2. user-672886 | | #2

    I'm surprised that in discussing options, the operational green house gas emissions benefit of an electric heat pump over an oil burner was not mentioned. While GBA's expert advice to stick with oil may be the cheapest solution, how does that recommendation accord with this platform's goal of "designing, building, and remodeling homes that are durable, energy-efficient, healthy, and climate-friendly"?

    1. bje11 | | #3

      Agreed. Also, surprised that no consideration was given to the cost of operating a new oil-fired boiler when oil is currently well over $100 a barrel.

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