How Far Should You Really Take a Home Retrofit?
The Real Retrofit Question
When a homeowner calls about a new kitchen or more space, and you notice air leaks, worn siding, a damp basement, and an old gas furnace, the real question isn't which product to specify. It's how far you should push this retrofit.
This was the focus of a BS and Beer conversation when Emily Mattern sat down with Rachel White of Byggmeister in Massachusetts and Josh Salinger of Birdsmouth Design Build in Oregon. Despite working in different climates and markets, both spend their days in existing homes, balancing comfort, cost, carbon, and the quirks of older buildings.
Why Existing Homes Are the Main Course
Rachel’s firm focuses exclusively on existing homes around Boston. This is partly because old New England houses are intriguing with their layers and surprises, but the bigger reason is climate math.
In Massachusetts, and much of the country, most buildings that will still be here in 2050 already exist. The state has a net zero carbon target for 2050, and while new high-performance buildings will help, they can't carry the whole load. The small houses, two-families, and triple-deckers that already line the streets are where the real work lies.
Josh sees the same from Portland. New construction consumes a vast amount of global material and energy, so we need to build better. Yet, roughly three-quarters of the homes that will stand in 2050 are already built, and only a tiny fraction receive meaningful energy retrofits each year. Without change, the math simply doesn’t work.
For both firms, retrofits are not a side quest; they are the main story.
Start With a Real Assessment, Not a Product Pitch
Both teams begin with a performance assessment. They avoid calling it an audit, as nobody likes that word, but the concept is the same: spend time in the house, use real tools, and pay attention.
Josh’s crew arrives with a blower door, an infrared camera, and sometimes a gas leak detector. They examine insulation levels, air leakage, duct routing, equipment, and ventilation, sorting findings into three rough categories:
Obvious quick wins, such as sealing the worst leaks or fixing poorly installed doors.
Solid mid-level investments, like upgrading ventilation or improving attic insulation.
Big moves that change the long-term story, such as exterior insulation or full system replacement.
Rachel’s team follows a similar approach, with a clear priority: Health and safety come first. Before discussing carbon or comfort, they check for asbestos, old wiring, moisture problems, pests, radon, and combustion safety issues. Josh shared a story about a water heater that also fed radiant floors without a proper heat exchanger, quietly creating a risk of Legionnaires' disease. The owner was unaware until someone checked.
Once the picture is clear, they discuss performance targets—not before.
You Are Serving the House and the People
Rachel mentioned something simple yet impactful: The house is a client too. Her team designs not just for the current family wanting a brighter kitchen but also for the structure itself and future residents.
If someone requests a beautiful new kitchen over a damp, moldy basement, they don’t just proceed. They address the basement. Sometimes they walk away if the owner insists on ignoring problems that could harm the building and its occupants.
Josh takes the same approach. When a house is unhealthy or damaged, his team outlines what they see and what it will take to fix it. If the owner insists on skipping those steps, they plainly state they are not the right contractor.
Most projects fall in the gray zone rather than extremes. A leak that occurs only during big storms, a gas furnace that still works but is poorly placed, or drafty yet historic windows. That’s where the conversation shifts to roadmapping.
They help clients decide what must happen now, what can safely wait, and how to avoid blocking future work. This might mean designing a kitchen today that leaves a clear path to address the basement later or planning trim and siding so older windows can be replaced without tearing the house apart.
When Climate Goals Meet Historic Rules
If you work in an older town, you’ve likely encountered scenarios like Rachel described in Lexington, Massachusetts. Her team worked on a house with sections dating back to the late 1800s. The original clapboard siding was in poor condition, and from a building science perspective, it seemed ideal for exterior insulation under new wood siding matching the existing look.
The local historical commission saw it differently. Due to a demolition delay ordinance, they could slow changes. They ruled that the original siding should be preferably preserved, allowing only a small portion to be replaced for over a year. Even after commissioners visited the house and saw the siding's condition, they upheld their ruling.
The retrofit plan had to pivot. For now, the team is insulating from the inside, sacrificing some floor area and making compromises. The long-term plan is still to add exterior insulation and new wood clapboards once the delay expires.
Nobody pretended this was ideal. The conversation highlighted the tension in many older communities. Preserving character and history matters, but a climate-focused retrofit that protects structure from water and reduces energy use is also a form of preservation. There’s no simple answer, only careful navigation and patient clients.
Deep Retrofit or Many Moderate Ones
The conversation turned to a strategic question: Is it better to invest heavily in a few deep retrofits or bring many more homes to a solid, moderate standard?
Rachel has long argued that the sweet spot is shifting towards doing slightly less load reduction and more complete electrification. She prefers a house with good but not extreme insulation that has fully eliminated on-site fossil fuel burning over one with a super low heating load that still uses gas.
Josh shared a story illustrating why this matters. His team helped a client who wanted all mechanicals inside the conditioned space without foam insulation. The house had a vented attic, so they turned the entire roof into a conditioned assembly, installed high-performance membranes, and moved all equipment into that new volume. The technical solution was beautiful, achieving a net-zero target, but the work cost hundreds of thousands of dollars and didn’t change the home’s day-to-day feel. The kitchen remained dark, and the front door still stuck.
For that client, the project made sense because the performance goal was a priority. For the climate problem as a whole, the team wondered how many moderate, all-electric retrofits that same budget might have delivered.
There’s no single correct number, but the guiding idea is clear: We probably need fewer perfect projects and many more very good ones.
Electrification Is About Layout as Much as Equipment
Everyone agreed that moving away from fossil fuel appliances is important, yet they candidly discussed the complexities in existing homes.
Josh described a basement where a relatively new gas furnace sat under the area the family wanted to finish. The ducts were wrapped in old asbestos insulation and ran diagonally through joist bays, reducing headroom. From a design perspective, the clean move was to install a new heat pump system, eliminate the old ducts, consolidate equipment along one wall, and improve space and air quality in one step.
The owners understood the benefits: quieter operation, more space in the basement, better indoor air, and a path off fossil gas. They also felt the sting of letting go of a furnace that seemed new and paying for a system that wouldn’t obviously pay for itself in a simple payback period.
Rachel echoed this tension in another house, where mismatched systems made a gentle phase-out of fossil fuels nearly impossible. Ultimately, the only honest plan was to replace everything at once, resulting in a significant one-time cost.
The message isn’t that electrification is too hard. It’s that distribution, space, and timing matter as much as the equipment’s nameplate.
If You Live in One of These Homes, What Should You Do Next?
For homeowners, this can feel overwhelming. The good news is you don’t need to memorize every retrofit detail. You mostly need to look for the right process.
Ask questions like these:
Will you start with a real assessment that includes blower door testing, thermal imaging, and health checks?
How will you prioritize issues affecting safety and durability before discussing finishes?
Can you show me a roadmap of steps over time, not just a single project?
How will this work make my home more comfortable, safer, and easier to improve in the future?
If a contractor cannot answer these questions clearly, they may not be the right fit for a retrofit that touches structure and systems.
Final Pour
By the end of the hour, questions about siding, windows, dehumidification, heat pumps, and other retrofit aspects remained. This itself is a reminder that retrofits are not a single neat topic. They are at the heart of the building science challenge for the coming decades.
The shared thread from both coasts was this: Start with the house you have and the people living in it. Make it safer and healthier first. Respect history, but also respect physics and the climate reality we live in. Aim for practical, repeatable solutions, not just showpiece projects. And keep the future in mind so you never create work that your future self will have to undo.
By keeping these ideas in mind, you are already much closer to a home that feels better to live in and is more prepared for the future.