If your home was built in the 80’s or 90’s you are probably starting to consider a furnace replacement. Before making such a large purchase, and one that can effect the comfort of your home for years to come, you are probably considering doing some research into the benefits of replacing the old dinosaur in your basement. This article will help you sort through the hype and sales pitches you are likely to hear or read about.
A common sales pitch is that the 1980’s furnace in your basement is approx. 50% efficient and upgrading to the new 92% + efficient models will save you a fortune. This is not necessarily true. The efficiency of your furnace is measured by how much gas is burned compared to the heat that is actually transferred into your home, this is measured in BTU/hr. We will go into more detail in a later blog what this means to for, for the purposes of this article, what you need to know is that on your furnaces rating plate you will see BTU input and BTU output, so if your furnaces input is 100,000 btu and its output is 80,000 btu 20% of the gas burned is going up your chimney, making that model 80% efficient. Now this is at factory mint condition, over 30 years they get beat up and worn out just like the rest of us. They become less efficient as their components wear out and require more energy to perform, including the electrical for the blowers. So by the time you start to consider replacing the old girl, while there is no exact figure for every model, but it is probably operating in the mid 70% range. New furnaces can only be sold in the 90% range, this is achieved in many ways including more efficient motors, 2 stage and variable stage gas valves, but one of the best innovations is the secondary heat exchanger which captures excess heat from the exhaust gasses and turns it into useable heat. You will see that all furnaces do not have a chimney in the usual sense. They are vented by specially designed pvc pipe. This is for a couple reasons, but one of them is a great example of why these furnaces are so efficient. The exhaust gas is not hot enough to rise all the way out of a typical chimney and will typically condensate out and drop down, this is also why they have drains. I could go on and on touting the benefits of the higher, more efficient furnaces but this article is designed to dispel one myth…. Your old furnace is so inefficient that it is useless and should be thrown away immediately because it is draining your bank account.
So let’s do a quick comparison. Using the 100,000 btu furnace example from above
That 100,000 btu furnace is 30 years old, and operating at approx. 70% efficiency
The new base level models that I sell are 92% efficient
So the old furnace sends $30 out of every $100 spent on gas up the chimney
While the new furnace sends $8 out of every $100 spent on gas up the chimney
Let’s assume a 6 month heating season
Old furnace wastes $600
New furnace wastes $48
Now the facts and figures stated here are approximations, but its obvious which furnace most people would choose based on efficiency. But the idea that the old furnace is completely useless is simply not true, and if you are in a situation where finances are tight and your furnace isn’t broken and still operating safely, if you have to wait until you can afford the replacement it’s not the end of the world
If you have any questions regarding furnaces, fireplaces, or general heating, cooling, ventilation or plumbing related concerns, please do not hesitate to call the experts at Red Deer Heating and AC for your free consultation and estimate