Maine Passive House is proud to build homes with lower operational carbon impact through the use of well-insulated, air-tight envelopes. But we cannot deny the inherent burden of new construction. No matter how hard we try to source local materials and use better building practices, a new structure requires significant natural resources and land development.
The impact on the land starts with disturbing trees, rocks and soil on site, and continues as energy intensive materials like concrete, foam, steel are used to construct the structure. Even when significant effort is made to reduce the embodied carbon of selected materials, the resource demand of new construction is significant.
We commute to the jobsite every day, passing derelict houses in varying states of disrepair. We drive past homes with little to no insulation built in the 60s and 70s, running heating systems at full capacity to keep the owners warm on the coldest of winter nights. Every new house we build sits in stark contrast to the vast number of houses built long ago, which provide critical housing for Maine residents. We can’t ignore the reality of the existing housing stock in Maine. In fact, there are only seven other states in the nation with older housing stock than the state of Maine. Nearly a quarter of the houses in Maine were built before 1939 and half of all houses are 45 years or older. (1)
Even if all new construction adhered to the best known practices of building science and performance today, over 80% of our housing stock is still in need of upgrades. And for the first time in a while, it might actually make financial sense to do so. For decades it was less expensive to build a new house, rather than retrofit an old one. Now, with the cost of new construction skyrocketing due to post-COVID inflation, retrofits are once again cost competitive.
Maine Housing Report, published in 2019
Retrofits are critically important to reducing the carbon emissions of our current housing stock and improving occupant comfort both physically and financially. Retrofits help residents reconnect with their space, from the perspective of safety, design and comfort, while reducing vulnerability to volatile energy costs.
What is a retrofit?
We classify a retrofit as any renovation to an existing building with the specific intention to weatherize and improve the energy efficiency of the structure. Frequently, this means windows with a higher performance rating, added insulation for thermal comfort, and air-sealing to reduce draftiness and heat loss. Certain aesthetic updates may result from these projects, but the primary goal of a retrofit is functionality and energy savings.
General retrofit recommendations
Consider these things if you are looking into your own retrofit project:
1. Lot size, boundaries, and zoning - do you have room to do an addition on the property?
2. Where do you see the most potential upgrades? - If your windows, roof, and siding need replacement, we often recommend retrofitting as an opportunity to reduce the operational expenses of the home. However, if your windows, roof and siding are all in good shape, it is very disruptive (you wouldn't be able to occupy the space) to do an interior retrofit. Interior retrofits are incredibly rare and would only be considered if significant interior redecorating was desired (and if you were willing to lose some interior square footage).
4. Basement/attic finishes - do these spaces have wall and/or ceiling coverings? It's tricky to wire and plumb without a bunch of demolition if these spaces have been finished.
5. Shape of the structure and rooflines - a simple box is much easier for us to wrap with our membranes and insulation for better efficiency. Funky corners and attached porches/decks are tricky to work around.
6. Current heating source - this may come with some infrastructure that either gets eliminated in the process, used or repurposed.
7. Boots and hats - we make it a practice to avoid air-sealing your home if there are any leaks in the roof or wet basement issues. These would need to be addressed prior to anything else. Maine is tricky with moisture in basements. If the inspection reports say "can get wet in the springtime" you better believe it will.
What low cost weatherization can any homeowner do?
We are finding that an energy retrofit costs anywhere between $200-$300/square foot. However, there are some low hanging fruits that homeowners can do to seal up their homes and reduce their energy bills. These improvements include weather-stripping, installing storm windows or Window Dressers inserts, caulking/spray foam leaks, insulating pipes, getting an energy audit, and hiring vendors from Efficiency Maine to perform insulation/air-sealing.
Consider the following:
One of our primary goals in 2023 is to seek out more retrofit projects!
Please let us know if you have one in mind!
Retrofit Highlight: Barker Mountain Ski Chalet
Nestled at the base of Barker Mountain is a sweet, little ski chalet built in the 60’s by our client’s grandfather. This modest 1500 square foot vacation home is a testament to the humility of landowners from years past. There are two bedrooms, 1.5 baths and a loft. We have also updated two additional sleeping areas in the basement. This ski retreat was designed to endure the scraping of boots and accommodate many children and grandchildren so that the family could enjoy Sunday River together. A large window wall on the front of the house [pictured] showcases the natural beauty of the mountains and snow.
Our approach to this retrofit
Timing: This is an important consideration before undertaking any energy retrofits on a structure. Where do you see the most potential upgrades? If your windows, roof, and siding need replacement, we often recommend retrofitting as an opportunity to reduce the operational expenses of the home. This project had 40 year old siding and windows in need of replacement.
Exterior insulation: We are attaching 5” of EPS foam to the walls of this building and 8” to the roof to provide R19 to the walls and R32 to the roof in addition to the existing insulation. We discovered that the roof only had 1” of insulation above the exposed tongue and groove pine ceilings. This additional roof insulation is going to make a significant impact on energy savings as heat rises in these vaulted ceilings. We like to insulate the exterior because it allows us to preserve interior finishes like drywall, cabinetry, flooring, etc. We can minimize disturbances so occupants can still use the space and preserve interior square footage.
Re-creating the charm of the original house: This home had a handful of unique exterior finishes that we wanted to preserve or replicate in our upgrades to preserve the character. The house had T1-11 siding, which we used for the structural sheathing and covered in an air barrier and insulation. The siding we will be installing will likely be a channel rustic or reverse board and batten to give a similar look to the original. Since we were trying to minimize labor to keep costs lower, all replacement doors and windows were sized to be installed into the existing openings. We will also be reattaching the handmade shutters with a skier stenciled onto them.
Mechanical Ventilation/Dehumidification: As we improve the air tightness of these structures, we also need to consider how to get fresh air into the space. We added through wall units called Lunos to exhaust stale air and replace it with fresh air with heat transfer to avoid significant losses. The owner also requested a dehumidification unit to address the stale air and mildew smells from the basement when the house is unused for a period of time. These systems will improve occupant health and comfort significantly.
Material choices: Why did we choose EPS foam for exterior insulation (a more carbon intensive product) instead of an assembly that could accommodate dense-pack cellulose (a carbon sink)? We are practicing details for when wood fiber board becomes available through Timber HP, a company producing wood fiber insulation at a recommissioned paper mill in Madison. We would like to hit the ground running when that new product becomes available to us. The foam and fiber board are also useful to keep the project rolling on our own time schedule, instead of relying on a subcontractor’s schedule for blown in cellulose.
This delightful ski home is still under renovation, although we shut down operations so the owners could ski this winter (obviously!).
Stay tuned for photos of the finished product when we close out this summer!