In a recent Fine HomeBuilding piece entitled, "Taking Issue: Energy Upgrades Threaten Older Homes," Sally Zimmerman of Historic New England suggests that deep energy retrofits (generally considered to be an energy use reduction of 70% or more) are a "great[] threat ... suddenly looming" over historic homes. Her premise is that superinsulation--the retrofitting of the building envelope to dramatically increase R value and decrease air leakage--is inherently at odds with the values of historic preservation. This is a dichotomy that is wrong and unnecessary. It condemns historic buildings to hospice.
There is no greater threat to old buildings than to permanently accept them as poor energy performers. As we edge closer to a uniform efficiency standard that will apply to all homes (an MPG rating for buildings), both new and old, it would be tragic to deny historic buildings the opportunity to demonstrate deep energy performance - and with it, to sustain their value. It would be to deny them a future.
As it stands, there are a growing number of examples of old buildings benefiting from the TLC of owners determined to increase their comfort, decrease their energy consumption, and ease their impact on the earth, while preserving their historic integrity, and without the barrier of prohibitively high costs. (The cost of building envelope improvements, we've found, is relatively modest when taken in the context of any retrofit.) Here's one recent example:
This 1915 American Foursquare in Concord, MA underwent a deep energy retrofit. The external building proportions have been increased by 4 inches or more. Can you tell? (The full case study on this home is here.)
Zimmerman acknowledges that energy retrofits are necessary: "We must fit these houses for a new energy future...," but then appears to lose heart, worrying about a problem that we have yet to see emerge: "We can’t afford a one-size-fits-all approach. We need something more nuanced, particularly for those houses we consider historic." As it is, however, home performance professionals committed to working in existing buildings have already adopted a more nuanced standard. Their work is, by necessity, more complicated than new construction, and takes into account the structural and cosmetic peculiarities of any given home. Moreover, the science and techniques of deep retrofits are increasingly proven and predictable.
Clearly, deep retrofits will force some choices and get us thinking hard about preservation purity. Is a window inset in its case by a few more inches (to accommodate thicker insulation and for superior thermal performance) really a scar? How do you rationalize the best in class U-value .09 simulated divided light window made of fiberglass that is 4 times better than the EnergyStar standard, against it's closest wood version at a U-value 0.3?
Taking on these buildings is a meticulous and important act of intervention. Shrugging our shoulders and walking away would be a costly mistake, and one we don't have to make. We have the skills and technology to ensure that our historic buildings remain usable and outlast us ... beautifully.
Comments
Peter - As a practicing Energy Auditor I whole heartedly agree with your point of view. Each of us need to assess our homes and come up with a plan on how to improve its performance on efficiency, durability and sustainability.
EnergyAudits.com can help home owners find a local certified professional to test their home, give them a scope of work and safely get them to reduce energy consumption, increase comfort and save money over time.
Posted by Damien Flaherty on Jun 17, 2009 8:30amPeter -
I too agree with your views. Although I understand the views of preservationists as well, it is important to keep in mind that our residential building stock requires about 23 percent of all energy produced/needed out of our overall building stock, which accounts for 48 percent of all energy use/needs. This is quite a bit! And although Ms. Zimmerman is correct in saying that without proper knowledge of how buildings work (how they breathe and so forth) a deep energy retrofit could go horribly wrong in the hands of an inept professional. She also makes the statement that expecting older homes to adapt to us and our needs without any concessions in return is disrespectful. I respectfully disagree with this statement. The wonderful things about buildings is that they are more often than not extremely adaptable and grow with us. As long as we understand and respect basic physics that is. There is also the claim that often materials stripped from older homes during a retrofit end up in a landfill, thereby wasting an enormous amount of embodied energy. Again, I respectfully disagree. Often the materials removed can be -and are, salvaged and reinstalled. There is no reason to throw away trim and siding unless it is severely rotted. Properly removed and treated before re-installation, these materials can be reinstalled and the embodied energy captured for another length of time. Finally, deep energy retrofits to older homes will not destroy the rhythm of the rooflines, or the character of the neighborhood -not that I am suggesting she stated this. I am offering my opinion based on my inference of her statement. What deep energy retrofits do offer is renewal of homes for generations to come, and which are better prepared for the new rules of the game being set upon us.
Posted by Sara Sweeney on Jun 18, 2009 6:35amWhile the referenced article by Sally Zimmerman is excellent, I find I must agree with the comments of Peter and Sara. Preservationists are charged with maintaining our historic architectural past. In a modern world of "just add water" housing and "Edward Scissorhands" neighborhoods, this is a vital task to undertake to preserve the framework and soul of our architectural past.
Posted by Justin Jones on Jun 18, 2009 9:11amFrom a durability standpoint, historic homes are largely able to survive due more to their failings than their successes. An odd concept I know, but uninsulated walls, leaky roofs, and drafty rooms typically don't lead to the rotting and structural failings we see in modern houses because they tend to cancel themselves out. A roof might leak (water) but the overall leakiness (air) enables the house to dry out and survive. As one of my mentors, Joe Lstiburek often points out, old houses have a much higher "hygric buffering capacity" than modern houses. This is key as it is largely what allows these old buildings to survive despite their shortcomings. If a retrofit changes the existing balance that exists in an old house without recognizing the potential effects, the building could be doomed.
From an energy efficiency standpoint, no one would argue the large amounts of energy old houses use. Zimmerman mentions "superinsulation" several times in her article. I agree with her that going the route of "superinsulation" can often be very invasive to the historical fiber of a home but I want to stress that this is not always the only way to go.
Historical homes are certainly worth saving. To do so requires a certain expertise that often does not exist in the current homebuilding world. The vast majority of my 12 years of experience is in the new home field. Do I have a solid building science background, yes. Do I feel it is strong enough from a retrofit angle, no. I would not undertake a major energy retrofit of a historical home without additional consultation. New construction and retrofits are simply two different animals.
A problem I see as we move forward is that energy auditors, green consultants, etcetera are coming out of the woodwork. Not that there is anything wrong with that but these new consultants simply do not have the necessary experience to handle most of these projects. The bigger problem is that many of these green, green consultants may not recognize that and can jump into a project unprepared.
I realize I digress, so I will end with this. Historical buildings use a lot of energy. Historical buildings are worth saving and are worth the cost and effort to bring them CLOSER to modern energy efficiency standards. Can every old house be brought to say Energy Star standards? Probably not and we need to recognize this. Every house does not have to be Energy Star, LEED, or NAHB level. We need to focus on what we can realistically do. This can be done safely with an experienced consultant and a lot of care. The foursquare house Peter cites in his article is proof.
I came to this article via Sally's post in Fine Homebuilding. While the discussion here is informed and cognizant of the importance of historical buildings, there are many, many (as both Sarah and Justin point out) "professionals" out there that have neither the appreciation for historical preservation or the knowledge to properly implement a strategy for a whole house effieciency upgrade on an older house. Fortunately, many owners of these house do, and will stop most of the hack jobs.
I also think that Sally may have been speaking more about truly historical houses, rather than just old houses. There's a big difference in upgrading the 1915 house cited by Peter and an 18th or early 19th century home. To me, the historical significance of those houses outweighs efficiency gains from irreversible efficiency upgrades.
Keep up the good work, everyone!
Posted by john332 on Jan 2, 2010 2:15pmjohn332: Thanks for chiming in. As you point out, it is critically important that we begin to demonstrate historically sensitive deep energy retrofits. I tend to agree that many historically important homes are probably in the hands of thoughtful, caring owners, yet there are virtually no case studies for how to achieve deep energy reductions on historic homes. We hope to demonstrate one here in Freeport Maine on an 1875 house deemed to be very historically significant to the town.
The real issue, as our project has demonstrated, is that you can't achieve a deep reduction without addressing the building envelope. On our project, more than 2/3 of the energy savings result from insulation and air sealing.
Understanding that the envelope is where the savings are is critical to the retrofit/historic debate. While I can appreciate the concern about insensitive people hacking up building exteriors with superinsulation projects, the "don't touch the outside ever" approach, for the reasons I articulated in this post, is equally dangerous. It would be tragic, I think, if every home deemed historic were relegated to the status of poor energy performance.
Posted by energycircle on Jan 4, 2010 3:27amI agree -- it's worth asking out of all the historical houses out there, which ones will simply become too expensive to maintain or improve and fall into disrepair? I live outside of Boston, and the effort to renovate the Paul Revere house was very contentious. This is naturally an historical landmark -- and it's a museum, not a house. If we hope and expect that people will live in houses built in earlier centuries, doing their best to preserve their unique character, historical societies and preservationists must strike the right balance between the codes and technologies of today and what defines the true essence of a house.
Posted by tharrison on Jan 4, 2010 5:04am