Retrofitting and adaptive reuse of older buildings is often an ideal eco-friendly solution — bringing existing structures up to modern energy efficiency standards without the resource consumption of new construction. However, it’s critical to be realistic about which projects benefit from renovation and which are holding us back from a more energy-efficient future.

Sometimes, letting go of old buildings and starting fresh can have a better environmental impact. Here are some ways repurposing spaces can actually be less efficient.

When Upgrades Require Too Many Resources
Adding energy-efficient upgrades may be harder on some structures with construction that does not hold up to changes. For example, dealing with unkempt clapboard siding may make an energy-efficient building envelope much more costly, compared to renovating masonry. Therefore, fixing the structural issues may cost more than adding these improvements.

For example, some very old structures lack insulation in the walls. Locking down the air barrier to make heating and cooling these homes affordable and efficient could require removing the original siding to insulate and sheath the walls — hardly an easy or cost-effective task for most building owners.

It’s not just materials that make retrofitting challenging at times. In many municipalities with older housing stock, code requirements may insist upon protecting the original historic character of the building. While there are understandable historical and aesthetic reasons for these rules, the expense and challenge of finding compliant doors, windows and other features can put too much strain on renovators while sacrificing the energy-efficiency potential of newer models.

Sustainability advocates must also question what our goals are for energy-efficient development. Are we better served retrofitting all of our older single-family homes, or embracing denser multifamily construction in the regions that need them? This is a concern in urban centers, where housing shortages clash against high demand to squeeze residents’ ability to live comfortably in our biggest cities.

Ultimately, there is no black-and-white choice here. There is great value in updating our existing building stock for modern energy-efficiency standards. But the strain of inefficient construction, high standards for preservation and city development that isn’t meeting modern needs should also be taken into account — letting go of buildings that don’t serve us can have greater energy efficiency gains.

Reasons to Start With New Construction
With all of this in mind, here are a few instances when new construction makes more sense.

1. When Converting Offices into Residential Spaces
While it’s still unclear whether remote work will truly leave us with an abundance of unused commercial space, converting large office spaces into residential spaces seems like a great solution. However, changing the purpose and layout of a commercial office can be much more challenging as a renovation project, when more energy-efficient housing could be built from the ground up.

For one, the developers who own these spaces aren’t likely to invest in converting them to less lucrative housing without incentives. Beyond this, though, many of these structures don't lend themselves to residential properties. Modern offices were built to have expansive floorplans that would require extensive renovation to create apartment units with adequate access to windows.

Another issue is the placement of utilities. In offices, bathrooms are bunched near the building's center with minimal plumbing lines. For residential spaces, you need plumbing for every unit. In addition, an electrician will need to route electricity and run it through new meters.

There are creative and exciting projects out there to turn commercial spaces into mixed-use, sustainable buildings. All in all, however, it’s often more efficient to build new multifamily housing where an empty office space once stood.

2. When Adding New Housing and Apartments
Creating more dense housing through repurposing can be great for cities. But, as mentioned, many structures like offices aren't naturally made for adaptive reuse. Meanwhile, should the opportunity arise, older single family homes might be better served as multifamily housing in neighborhoods with rising prices and a high demand for accommodation.

With advanced technology and more efficient systems, new construction can be quicker and provide space for more households. This is essential in combating the current housing shortage. Today, there is an increased demand for housing and low supply inventory — which is
raising prices.

Renovating an older home for energy efficiency is a fantastic outcome. But building green while also allowing for more density in walkable neighborhoods would have even stronger long-term effects, like supporting population growth to create new parks or sustainable transportation investment. In these cases, building from the ground up can be a better alternative to renovation.

3. When Getting Rid of Structurally Deficient Buildings
Finally, old houses with structural problems cause more risk. They can lead to poor indoor air quality, increased energy consumption and safety issues. Some may also be unoptimized to deal with modern climate concerns like flooding. Therefore, getting rid of these old homes can be more beneficial than preserving them.

Upgrading systems might even cost more than they're worth to get the building to code. This has to be done before adding any energy-efficient solutions. What good will historic charm do if a building is only going to be washed away by coastal flooding or requires serious structural repair?

New Construction Can Be the Efficient Choice
Rebuilding or starting fresh is a tough choice in the construction industry. Repurposing buildings has many environmental advantages, such as reduced waste and energy consumption. It’s also popular with community members, who may have treasured memories of the existing space.

However, it’s important to recognize when it's better to start over. Historical houses have structural elements that make adding upgrades more complex and costly. Some spaces like offices require significant layout changes to create homes, so starting new eliminates using extra materials.