High-efficiency furnaces designed to save energy and money can lead to frozen pipes and expensive repairs when installed in mobile homes, a plumber says.

Go Public has seen frozen pipes and sewer back-ups caused by water from high-efficiency furnaces freezing in pipes and furnaces that shut down on cold days.

The problems are caused by the design of high-efficiency furnaces, which squeeze every last bit of heat from the burned gas, producing water when moisture in the exhaust condenses.

Mobile home-owner Weber

Ronald Weber owns two mobile homes. (CBC)

The resulting trickle of water is discharged into a drain, but in the space under a mobile home the trickle can start to freeze.

“They haven’t thought through the consequences of having them in mobile homes,” said Ken Stashko, a plumber with more than 30 years of experience around Athabasca, Alta, as he crawled under a mobile home, hauling out chunks of yellow insulation, frozen solid with leaked sewage.

The family in the home had been away for two days. In that time, he said, the trickle of water from the furnace froze in the sewer pipes.

When the family returned and began using toilets, showers and laundry, the sewage had nowhere to go, eventually backing up in the home, costing about $1,500 to repair.

The problem started in the past three years when high-efficiency furnaces became mandatory, Stashko said.

His solution is to install a pump that collects the condensation then flushes it all at once, and to wrap drain lines with electrically-heated tape to keep them from freezing.

Stashko said it costs between $1,000 and $1,500 to install the heat tape plus the cost of electricity when it’s in use.

The extra cost of a high-efficiency furnace and the modifications required for its use in a mobile home make it a false economy, he said.

“There is no money saving, no efficiency. You’ll never make up the difference,” Stashko said.

Owner won’t trust furnaces in cold weather

Ronald Weber has two brand-new mobile homes sitting empty, waiting for buyers.

He said he doesn’t trust the furnaces to keep running in extreme cold weather.

“If someone’s occupying the place, flushing the toilet, got water running through the sewer system, you probably won’t have a problem,” he said.

'I think it’s ridiculous. We don’t need these problems'- Ronald Weber, mobile home owner 

“But if you go on a holiday you’re going to have a problem unless you have the sewer system insulated and heat-traced,” he said.

Even then, he said, pumps and heat tape can fail or wear out.

His solution, until someone moves in, is to disconnect the furnace’s drain tube from the sewer line and run it into a bucket which he dumps every other day.

“You shouldn’t have to do this,” Weber said. “I think it’s ridiculous. We don’t need these problems.”

Alberta alone in requiring high-efficiency furnaces

Federal legislation requiring residential furnaces built after 2009 to be high efficiency specifically exempts those installed in mobile homes.

But a circular quirk of Alberta law makes high-efficiency mandatory for mobile homes in this province.

Hank Starno, president of MHI Canada, the national trade association for manufactured home builders, said manufacturers are forced to install high-efficiency furnaces because of the Alberta Building Code.

The code treats mobile homes the same as conventional single-family houses. In Alberta that effectively makes a mobile homes a house and subject to the federal requirement for high-efficiency furnaces.

“The problem is when you try to apply the Alberta Building Code to a type of house that’s normally built under a different code,” Starno said.

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“We don’t know the rationale, other than somebody said we only need one code here.”

However, Starno says he’s not aware that high-efficiency furnaces are a problem in Canadian winters, provided the plumbing systems are properly insulated.

Ken Stashko disagrees. He’s had three calls already this winter about frozen plumbing caused by frozen condensate from furnaces.

“I’m being told I am responsible because I am an installer,” he said.

“I don’t want to install anything that doesn’t work properly. I don’t want to have to crawl around at 30 below...soaked in sewage...more than I need to,” he said.

“I already have to, but to have to do it when it’s just a poor design and poor engineering?”

Stashko said high-efficiency furnaces shouldn’t be installed in mobile homes but says he can’t get anyone at the provincial government to listen.

“They shrug their shoulders and say ‘It’s the building code’”, he said.

Stashko wants the provincial government to recognize there’s a problem and take action.

“Until the engineers ... can give us a solution on what to do with the condensate that does not take up more energy and is a reliable solution, until then, put in a mid-efficiency.”