Furnace Energy Efficiency - It Is Not That Simple…

With the return of cold weather, I find myself listening the furnace running and feeling guilty about all the energy I’m using heating my home. The environmentalists have done an excellent job of making us feel guilty about our lifestyles and persuading us to become more energy efficient. After all, we have all heard if we don’t take the bus, that the sea levels are going to flood half the populated world and that if we don’t stop driving cars, we are going to be vacationing at the North Pole in the winter to get relief from the heat. 

However, when we look at energy efficiency of our homes, it is just not that simple to get an environmental benefit from changing our heating equipment.

What is Really Efficient?

A new high-efficiency gas furnace ideally turns 95% of the energy it consumes into usable home heating energy while a 20-year old mid-efficiency furnace is more likely about 80% efficient. So that means for every $100 spend on natural gas this winter, you would $15 more worth of energy from the high efficiency furnace. Sounds great, until you start to look at the total environmental and business case for updating your furnace:


Source: fortisbc.com/NaturalGas/Homes

  1. Life Cycle Savings - Fortis BC says the average home in the lower mainland would spend $565 on natural gas for heating with a mid-efficiency furnace, or $480 per year for high efficiency. That would be a savings of only $85 per year. With an expected service life of 20 years, you stand to save $1,700 in the life of the equipment. How much does a high-efficiency furnace cost? About $3,500. There is really no life cycle cost benefit in our climate to replace an operating furnace.
  2. Installation Errors - In order to get that 95% efficiency rating, the installer (and/or builder) have to have a ‘perfect’ installation. When retro-fitting a new furnace, there will never be a perfect installation. For example, omitting a fresh air intake (common when the furnace room is central in the home) from the high efficiency furnace may drop the efficiency rating by 5-10%. Now the ‘high efficiency’ furnace is only operating at 85-90% efficiency (or a $566-1133 life cycle savings).
  3. Energy to Produce Equipment - To make your new furnace, mining equipment in will need to extract the ore, a refinery will need to run massive smelters, toxic chemicals are needed to produce the circuit boards, and a fleet of trucks, trains, and planes will move the parts around the world numerous times until they are finally delivered to your home. This process consumed huge amounts of energy and in many countries of the world, that energy may have come from unclean sources like high sulphur output coal plants. Plus, we now need to take out your old furnace and safely recycle the materials. A tremendous amount of ‘energy’ went into getting you a new furnace before you even start to use it.
  4. Heating Impact to Global Warming - According to the US Government EPA in 2011, home and commercial heating was responsible for about 11% of global warming causes. As a home and commercial inspector, I can tell you that most commercial structures are horribly inefficient compared to homes, so even without this number broken in more detail, heating your home is a small part of your lifestyle impacting global warming. Plus, emissions are actually DOWN in heating energy in the last decade because of natural equipment changes and improvements to energy efficiency in new homes. What am I getting at here then? If you want to save the environment, it will take more than just a new furnace and there are more effective lifestyle changes you can make about what you eat, where you shop, and what you drive that should take priority. 

Final Thoughts

I’ve often told clients, the least expensive furnace to operate is the one you own today. Certainly from a cost of ownership perspective that is true but I believe the environmentalists are wrong in making you feel guilty about using your old furnace. Removing and replacing a functioning furnace would require huge amounts of new energy and you would be ‘wasting’ the energy that went into making your old furnace before its life was complete. That said, we need to heat our homes and at some point your old furnace is going to break down and the government won’t let you buy anything but a high efficiency furnace to replace it. 

So if you want to be a good steward of the environment, lower the thermostat, put on a sweater, and nurse as much life as you can out of that old furnace, and when the time comes to replace it, you will have done the environment (and your wallet) a favour.

By James Bell - Owner Solid State Inspections Inc.