Making your historic home more energy efficient

By Curtis Drake, LEED AP

How many of us have felt frustrated in the last few years with energy prices soaring, the planet warming, and the cost of commuting rising?

The green movement encourages us to use less (which is easier said than done) or to turn to technology to increase the efficiency of our cars, appliances, and homes. Some of these technological changes are fairly simple. A new energy-efficient refrigerator provides real energy savings. Yet when it comes to our historic homes, we feel compelled to leave them as they are because we recognize they were built in another time, under a very different set of rules. Many of us understand the intrinsic value in the charm and antiquity of the older house and wonder if we can have our green cake and eat it too.

In answer to this question, a great starting place is simply recognizing that with your historic homes you already have a big head start.

The materials it took and labor to assemble your home years ago continue to serve essential needs for shelter, materials like solid, old-growth wood, copper, lead, and brass. These materials are not only durable and beautiful, but they are increasingly rare and costly in today's marketplace.

Such an idea is referred to as embodied energy: the energy required to grow, harvest, and manufacture the materials used to build the shelters we call home. Based on this calculation, we are actually ahead of the energy game.

We must keep in mind that calculating the worth of these older homes is not simply limited to its wealth of embodied energy. We must also consider that most of our older homes are located in residential urban areas built at a time when two miles from downtown was considered a long way out. Even a mid-century home can often claim a modest commute of less than 20 miles. These homes are often adjacent to public transit which can save a lot of unnecessary miles on the car. Finally, most of our older homes are more modest in size and pack more quality space in a smaller footprint than today's average-size bloated home.

Faced with these facts, we cannot simply accept the increasingly popular illusion that the state-of-the art new "green" homes are the only or best way to live sustainably. Our historic homes are not only more durable, they also offer many opportunities to incorporate energy saving features of the most advanced homes today. Technological advances are becoming more affordable and more accessible to the homeowner than ever before.

So what will allow us to retain the historic fabric of the home while making some changes to substantially reduce our carbon footprint?

First, take stock of the features around your house that are already contributing to energy efficiency. Perhaps you have recently updated kitchen appliances and light bulbs with Energy-Star rated equipment. If you have installed a new heating system or water heater recently, you know these systems are significantly more efficient than either were even as few as 10 years ago. Or perhaps your home has passive design features such as broad roof eaves or awnings that shade the windows from direct sun during the hot months of the year.

Second, most homeowners can seek low-cost, quick pay-back measures to reduce energy use to offset the increasing electricity and gas costs. Start with your utility. SDG&E offers a reduced energy fee if you allow them to regulate your water heater and air conditioning. Or consider installing a programmable thermostat allowing the air conditioning or heat to idle when you are away at work, turning on again just before you get home.

If you live in a cold area of San Diego County, you may want to consider adding a layer of attic insulation of R-19 (about 6 inches) or R-30 level (about 10 inches) which can result in a huge increase in efficiency if the house has little or no insulation. Unfortunately, walls are another story and cost more to insulate. Keep in mind the heat loss through walls is considerably less than through roofs.

If you've already made a few of the simple changes, you may now be ready to spend a few dollars. Before you ponder replacing the windows, remember that few things negatively impact the historic fabric of your home as much as window replacement. The windows in a historic home are primary to the historic appearance and, replacements are never as graceful as the originals, especially since dual glazing normally enlarges the size of the wood pieces between the glass panes and can look heavy. Further, that wavy glass and those leaded glass transoms are irreplaceable. Only 10-25% of the home's energy is lost through the windows.

Consider the following list of options that can actively reduce your energy costs and not harm the appearance of your home:

Solar Hot Water
Usually on the back of the house
Solar attic fan
Wall or rooftop units are small and reversible
Interior storm windows
Invisible from the outside
Water heater
Blanket and pipe insulation
Wood stove or fireplace
Wind Generation
In a discreet or rural location
Window weather-stripping
New or upgraded

These are but a few modifications available that are discreet or are reversible in the sense that they can be removed and the original character of the house is still intact. Most high efficiency homes incorporate no more than these types of equipment. In the last five years many residential-scaled items on this list have been developed and are more affordable than ever before.

Once historic homeowners take a moment to consider the many options for improving energy efficiency, we realize we can make significant changes without harming the historic fabric of our historic homes. The key is to methodically assess and to improve low cost areas before moving up to the more costly improvements, always keeping the integrity of your home in mind. Finally, recycle as much construction debris as possible. Local landfills provide a list of materials eligible for recycling.

In the end, we can feel empowered again and have some control over our energy costs. Just remember, take it slow and think twice about any changes when working with historic features. We chose our homes because of their historic features. It is our responsibility to save those features even as we try to save energy.

Energy Efficient Rehab Websites

Boulder, Colo. Historic Building Energy Efficiency Guide
bouldercolorado.gov/index.php?option=com_content&task=view&id=8217&Itemid=22
(While not everything on this website applies to San Diego's climate, this site for the City of Boulder, Colorado is very informative)

Do It Yourself Energy Assistance Analyzer
energyguide.com/audit/baintro.asp

Energy Efficient Rehab Advisor (homeowner tool)
rehabadvisor.pathnet.org/index.asp

Energy Star (guide to energy efficient appliance and equipment)
energystar.gov

Green Building Rating Systems
usgbc.org
architecture2030.org

Historic Wood Windows Tip Sheet
National Trust for Historic Preservation
Windows Tip Sheet (pdf)

Home Energy Saver (The First Web-Based Do-It-Yourself Energy Audit Tool)
hes.lbl.gov/

Smart Energy Design Assistance Center
smartenergy.arch.uiuc.edu/index.html

Editor's note Thanks to NTHP Forum. As we were working on compiling a similar list the new Forum arrived and made life oh, so much easier! Thanks Forum!

Curtis Drake is a principle with Heritage Architecture, one of the leading preservation architecture firms in the western United States. Curt is currently serving as President of SOHO. Illustration courtesy the author.