With the increased interest in lowering greenhouse gas emissions, there’s a lot of talk about retrofitting houses to make them more energy efficient, comfortable, and less expensive to heat and cool. While all homeowners will be keen to lower their utility bills and make their homes more comfortable, not all homes are well-suited for retrofitting. Some will be very expensive and challenging to retrofit effectively, especially the older they are. Here are a few typical problems and limitations to consider when retrofitting Canadian houses.
The cost of retrofitting can exceed the value of the home
If you live in a house that’s over 75 years old and its building envelope (the foundation, roof, walls, doors, windows, ceiling and their related barriers and insulation) has never been upgraded, there is likely only a minimal barrier between the inside and outside of your home, even if it is a double brick house. This can be confirmed with an EnerGuide evaluation of the home that will assign an energy efficiency score– an EnerGuide rating. Old homes typically have very low scores. At Green Energy Doors Open 2016, Coolearth Architecture Inc. advised that they expect to spend $106K + HST on a drafty, old Toronto semi to make its building envelope 25% more energy efficient, with $19K of this sum to be spent on triple pane windows. While Coolearth said the property was valued somewhere in the $600K-$700K range, I’m sure this number is based largely on the value of the land and not the house itself. Based on my experience, I would be surprised if an appraisal valued the structure at much more than $100K. This would make the cost of upgrading the building envelope of this energy inefficient semi greater than the value of the house, with only a 25% gain in energy efficiency. And, considering the low energy efficiency of the pre-retrofitted semi, the overall energy efficiency of the semi will still be relatively low after these retrofits.
Retrofitting can make other repairs more necessary
For example: if a house has existing air quality issues like mold, making the house more air-tight to minimize drafts and lower the energy required to heat or cool the house, can exacerbate this issue and associated effects on health like chronic wheezing. Why? Because minimizing drafts lowers the house’s indoor-outdoor air exchange. With mold, the roof, walls, floors and foundation can all be affected. It’s important to be aware of and make these repairs at the same time.
Retrofitting typically will not result in a highly energy efficient home
While a certain level of retrofitting is possible, homeowners must be aware that old houses will never achieve a high energy efficient status without great expense. They were not designed and constructed to be energy efficient – this simply wasn’t a concern or criterion. In contrast, a newly built, highly energy efficient home is both designed and constructed to be so. Because the building envelope of these homes is so air-tight, this also involves integrating controlled ventilation – mechanical ventilation systems to ensure there is adequate ventilation to prevent excess humidity, moisture issues and poor air quality. Other design considerations include things like the orientation of the house and the location of windows and doors.
Consider rebuilding old homes
Lowering greenhouse gas emissions is important, but I think we should be practical about how we approach this goal. While retrofitting may seem like a quick solution or a way to save that charming old house with some impact on the energy efficiency of the house, it’s not the practical choice for old homes if the cost of retrofitting exceeds the value of the house and does not result in a substantial increase in energy efficiency. This would seem especially silly if the retrofitting will not also result in a substantial increase to the expected lifespan of the house.
If the costs are high, the gained energy efficiency is low and the house is nearing the end of its valuable lifespan, a better decision is to tear it down and build a high energy efficient home instead. This way you can live in a home with low greenhouse gas emissions, while also benefiting from all the other comforts and advantages that come with a new home, including a design suited for modern living.
If you are interested in learning more about how you can rebuild your home, please contact me at firstname.lastname@example.org.