Early in 1995 the Ministry of Consumer and Commercial Relations (MCCR) announced a program to replace up to 20,000 mid-efficiency gas furnaces in Ontario, because their plastic vent pipes were prone to failure, and might leak carbon monoxide into the house. Other sources indicated the number might have been as high as 40,000 - but no one knows for sure.

The crux of the problem was that no other type of vent pipe had been approved for use with mid-efficiency furnaces.

Hundreds of home owners planned to sue the government, the manufacturers and others for refusing to pay for the entire replacement. At that point, home owners were expected to pay about $1000 of the estimated $1500 cost to exchange the furnaces for high-efficiency models, which would function safely with plastic vent pipes currently available. The home builder was to pay $200, the ONHWP $200, and the gas companies $100.

By the end of 1995 neither the Government of Ontario, which approved the faulty vent pipes, nor the manufacturers had made any contribution toward the cost of replacements in private homes and businesses. But the government did pay for replacements in government-funded non-profit and co-op housing.

And apparently, the program offered nothing to people who had already replaced their mid-efficiency furnaces before this program was announced.

On September 12, 1995, the Ministry of Consumer and Commercial Relations issued a Safety Order requiring all owners of heating appliances with high-temperature plastic vents to have these systems corrected by August 31, 1996. Gas utilities and propane suppliers were required by Ontario law to discontinue the supply of fuel to appliances which had not been corrected by the deadline. Correction consisted of replacing the defective vent with an approved alternate vent, if available, or replacing the whole heating system.

Two vent pipe manufacturers in Toronto claimed they had safe, effective replacement vent pipes (a special grade of corrosion-resistant stainless steel) which would solve the problem with mid-efficiency installations. These replacement pipes had not yet received approval, and for some furnaces, replacements were never approved. One manufacturer asked the Premiers office to spend some of the millions ear-marked for furnaces in government-funded homes, to speed up testing and approval of the replacement pipes. The upgraded vent pipe installations typically cost a little over $400 per house.

In theory at least, all affected furnaces should have been re-fitted or replaced, by August 31, 1996.

However private home inspectors were finding some of these heating systems still in service, with the original hi-temp plastic vent pipes still in place, as late as the summer of 1997. It is entirely possible that some still exist today. Home owners should watch out for plastic exhaust vent pipes labelled Sel-Vent, PlexVent or Ultravent. (or any vent other than those in service on high efficiency furnaces, which are labelled ABS, PVC or CPVC, and are acceptable)

A licensed gas-fitter/installer should be consulted, if own a mid-efficiency furnace and you are uncertain of the vent pipes attached to it.

All owners of gas heating appliances should have CO (carbon monoxide) detectors in service, and have their appliances inspected regularly.