Sign In

Fix it or replace it?

​When there’s no cure for an aging furnace

Joan Churchill

Although it was an unseasonably warm and sunny January morning the day I moved into my new (to me) house, there was a bite in the air. And by the time the sun went down, I could see my breath . . . while sitting in the living room. The furnace wouldn’t fire up.

It was quickly determined that it just needed a pilot relight. So that evening I had heat. Barely. The furnace kicked in with a deafening, grinding howl and then died before the thermostat reached 18° Celsius. (I’d set it to 20°.) But like a cat with nine lives, it eventually came back to life, cranked the heat up to 18.5, and then died again.  I wrapped myself in a blanket and grumbled about how I was going to survive the fixer part of my new house, if I didn’t even have reliable heat.

My investigation the next morning revealed a furnace filter older than most teenagers. Perhaps why it kept shutting down? A dirty filter can cause a furnace to overheat and not work very efficiently. A quick trip to my local hardware store and the problem was solved. That night with a fresh new filter in place, I had a little more heat, and the furnace stayed on until it reached the temperature setting I’d programmed on my new thermostat.

But I knew that if this furnace and I were to get along, I’d need some professional help. Heck, it was only 18 years old. I should be able to get a few years out of it, right? I called a natural gas contractor for a service and inspection. He provided a 21 point checklist that gave me peace of mind and hope I’d have heat, at least for this winter. But his long term prognosis was not good. A new furnace was recommended. I got through the winter—luckily it was a mild one—and began looking at ways to finance a new furnace.

Creative financing and rebates

I didn’t have enough equity in the home to get a secured line of credit and I wasn’t willing to pay 10 or 12 per cent interest on a loan. But a little research dug up some savings. I was eligible for a $700 rebate from the federal government* if I installed a high-efficiency model, plus the furnace manufacturer offered a rebate, and I found a local credit union that offered a low-ish interest, long amortization loan specifically for home energy efficiency renovations.  The idea being that my low monthly loan payment would be partially offset by the energy savings on my gas bill.

So one hot July day, I had my furnace replaced. Being that it was summer, I was able to spend time shopping around for the model I wanted and get a few quotes. Plus, gas contractors aren’t as busy in the summer and there’s no chance of being without heat on a cold winter’s day.

The model I chose was 95 per cent efficient and had an extra quiet variable speed motor that could circulate fresh air throughout the house all summer long.  So I got to use it even before the first frost.

My savings journal

The first full winter with my new furnace, I had evenly distributed comfortable heat. Mind you with insulation still to be done, the heat never stayed long, but the furnace never failed to head the call. Still, I used a lot less energy—about five gigajoules a month—than the prematurely aged clunker did when the previous occupants lived in the house.  Mind you I was also diligent with keeping the thermostat settings to a minimum.

  • Between October and December 2008, with a mean temperature of 5.8°, the old furnace consumed on average 13.5 GJ per month. (The house was vacant during this time period in 2009.)
  • Between October and December 2010, with a mean temperature of 6.1°, my high-efficiency new furnace used an average of 8.9 GJ per month.


Read last months’ story, Old house doesn’t have to be drafty


Joan Churchill spends her days writing about energy efficiency for FortisBC. In her spare time, she’s renovating her house and taking care of a houseful of fur kids.

*Government of Canada’s ecoAction program ended in 2012.