Ask any builder whether building new or doing a renovation is more challenging, and you’ll get a clear answer – renovations are harder and more complex. A deep retrofit is a renovation intended to make a building net-zero-ready. The following are some challenges and considerations of deep retrofits. The Retrofit Road Map aims to equip homeowners, builders and other professionals with the knowledge they need to surmount these challenges.
Costs
The cost of doing deep retrofits is by far the biggest barrier. The high initial cost of well-planned deep retrofits encourages isolated, piecemeal upgrades that usually make the long-term total cost even higher. It is one reason that the piecemeal approach is still so common, in spite of its ineffectiveness.
Retrofits are often more expensive than can be justified by simple energy savings payback calculations. The numbers look a lot better when you consider the Total Cost of Ownership (TCO) of the building. Total Cost of Ownership calculations, in addition to including the long-term savings in energy costs (with expected escalation in those costs based on inflation), also include the cost of maintenance and repairs—including the ability to catch up on existing maintenance needs—durability and the longer expected lifespan, and resale value and possible incentives.
The significant side benefits to deep retrofits—like healthier indoor air quality, luxurious comfort, improved durability and resilience, a beautiful new look, and being able to look your kids in the eye—add to the value side of the equation, but they can be difficult to quantify.
Complexity
While cost is the biggest barrier, the complexity inherent in most well-planned deep retrofits is a barrier that can stop teams from dialing in the most cost-effective set of solutions.
The range of buildings and building types that we need to retrofit—basically all of them—is broad. This will take a broad range of solutions. When costs are so critical, choosing the right set of solutions for any given project becomes a make-or-break decision.
For residential buildings alone, there are single-family homes of all sizes, shapes, ages and conditions. Multi-family buildings range all the way from wood-frame duplexes to concrete and steel high rises. Each building was built according to its era’s prevailing construction practices, forms, and building codes. Over time, those codes, practices, and materials have evolved.
Many homes and buildings have undergone renovations, recladding, replacements, additions, and other improvements—including energy upgrades—that add to their variability. These all change the starting point and the optimal solutions for particular retrofits.
Early days.
Deep Retrofits are a new undertaking. Some solutions can be found from techniques used in new net-zero buildings, but many still need to be developed or adapted to the countless permutations that will be encountered. As more retrofits are finished, this will all get easier and more routine. Some experienced deep retrofit contractors can walk into a building and know exactly what to do.
Building science
Adding new layers to a building to control heat loss and air leakage can slow down the drying potential in previously leaky, underinsulated buildings and increase the risk of damaging moisture buildup. Successful deep retrofits avoid these risks by using details and techniques that are guided by good building science. First, do no harm.
Avoiding the piecemeal upgrade trap
Unfortunately, it is too easy for homeowners to fall into the piecemeal upgrade trap, making improvements to a building without any plan to achieve net zero. This slapdash approach can lead to unrecoverable sunk costs and prevent the building from ever becoming carbon neutral.
Even government grants for homeowners can inadvertently promote piecemeal retrofits by only funding certain upgrades without requiring a net-zero plan. These programs are getting better as policymakers adopt a more holistic, house-as-a-system approach to structuring these grants, with net-zero-ready as the ultimate goal. These homeowner grant improvements are encouraging progress that will prevent piecemeal upgrades that lock in emissions.
Another emerging concept in the retrofit movement is the shallow retrofit, which can also create confusion. As the name suggests, a shallow retrofit involves smaller upgrades and results in less energy savings. A properly executed deep retrofit will make a building at least 50% more efficient, whereas a shallow retrofit achieves significantly lower efficiency.
A shallow retrofit is acceptable if it is part of a plan to make the building net-zero-ready later on without redoing or undoing any upgrades. Without such a plan, a shallow retrofit will have the same outcome as a piecemeal retrofit, making it difficult, if not impossible, to achieve net-zero in the future.
The similarities between shallow upgrades and deep retrofits obscure the change in mindset needed for residential retrofits at the scale Canada needs to address the climate crisis. Both save emissions, but isolated upgrades, as practiced and encouraged since the 1970s oil crisis, tend to lock in the remaining emissions.
It cannot be overstated – do not fall into the trap of doing a piecemeal retrofit that will never get a building to net-zero.
OTHER CONSIDERATIONS
Upfront Carbon
As if deep retrofits weren’t complicated enough, the emissions from the materials and activities that go into them also need to be considered. These upfront or embodied carbon emissions can be higher than the ongoing operating emissions that are saved. Typically, these emissions are much lower than for new construction with new foundations—new everything—but they are not always trivial. If high embodied carbon emissions materials are being used, it is important to do the math. There are several calculators available, like this one.
The best deep retrofits use as low emissions materials as possible.
One chance
Deep retrofits are major, expensive interventions. Keep in mind that, however you leave it, that’s how it will be for the long haul. Any upgrades you make now will make future work or redos almost impossible because the money will be gone, and the business case will be worse. Realistically, there is only one chance to get it right for any given building.
The ‘While you’re at it’ opportunity
Deep Retrofits present once-in-a-building-lifetime opportunities for other improvements and repairs. For example, if you are replacing the windows, it would be foolish not to take advantage of the opportunity to enlarge or move that window that’s been driving you up the wall. Doing it later, working around a new air barrier, several layers of insulation, and new siding and trim will be difficult and costly. Other examples include fixing foundation leaks and grading problems, egress deficiencies, radon and mitigation, or even adding more space. Doing these kinds of add-ons during a retrofit makes a lot of sense, but they can stress the budget.
Conclusion
Deep Retrofits are complex, but not necessarily that complicated. None of the many tasks or considerations is all that difficult. It’s just that there are so many of them that need to be considered at once in order to do them affordably without missing opportunities and wasting money.
