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Energy Advice for Owners of Older and Historic Homes

About This Page

This guide was compiled by the National Trust for Historic Preservation with assistance from the Environmental Protection Agency. It was developed with input from several national and state preservation agency partners.

This page provides links to non-EPA web sites that provide additonal information. EPA cannot attest to the accuracy of information on that non-EPA page. Providing links to a non-EPA Web site is not an endorsement of the other site or the information it contains by EPA or any of its employees. Also, be aware that the privacy protection provided on the EPA.gov domain (see Privacy and Security Notice) may not be available at the external link. Exit EPA Disclaimer

Contact Information

Yolanda Bouchee (bouchee.yolanda@epa.gov)


Do you live in a historic home? Are you wondering how to lower your energy bills without losing features that give your house its character? Are you concerned about how your decisions might affect the long-term maintenance or condition of your home? This guide is designed to help you make decisions about how to increase your home's energy performance in a way that maximizes energy savings while preserving the historic character of your home.

Historic homes were constructed using different techniques and materials than most modern structures. They were typically built with environmentally-friendly features such as:

Older homes can be made more energy efficient. They simply need to be treated with a thoughtful, whole-house approach.

Maximize Your Home's Original Energy Saving Features

Historic homes have many inherent sustainable features. Before the middle of the twentieth century, most homeowners couldn't rely on comprehensive and fully automated, controlled, and mechanized heating, cooling and ventilation systems, because they did not yet exist. Instead, these buildings incorporated a number of passive or manual features that responded to the need for heating, cooling, and ventilation.


Simply closing the shutters or curtains on the hot sunny side of the house during the day will keep the house cooler. For free air conditioning when humidity is not high, open the windows and/or doors on the lower level of the cooler side of the house and then open the upper sash of the windows or an attic window to exhaust the warmer air at a higher level of the house. This creates a cooling, whole-house draft.

Warm climates:

Colder Climates:


Although these features are not present in all historic homes, most older houses incorporate at least one of these passive or manual systems, helping reduce the need for mechanized heating, cooling, and ventilation. Owners of older and historic homes can continue to use these practical features as they were originally intended, or rediscover them, making use of their great energy-saving potential.

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Improve Your Home's Energy Efficiency

Start With an Energy Audit

Energy audits provide the best way to identify air leaks in your home. While some utilities and local governments offer free audits, it may be worth the expense of hiring a professional energy auditor to do a comprehensive assessment. This comprehensive audit will go beyond identifying obvious energy upgrades and will create a roadmap of where and how to best make improvements in your home. This is even more critical with historic homes because air sealing can dramatically alter how moisture moves through the structure.

Even if you do your own basic energy audit, it's important to establish a baseline for your energy usage so that you know if the changes you make are effective, and to calculate your payback analysis. You can establish a benchmark for your energy usage by analyzing your energy bills for the last twelve months (or longer if available). For more on how to calculate a benchmark for your home's energy efficiency, see the worksheet in the Helpful Tips & Resources section.

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Air Seal


A gap of just 1/8 of an inch under a 36-inch door lets in as much air as having a 2.4 inch wide hole in the wall. Since people often adjust the thermostat and leave heat running longer when they feel a draft, preventing air infiltration can greatly reduce energy usage. Sealing up those cracks will make you feel comfortable and keep more money in your pocket. Remember for every cubic foot of heated or cooled air (that you have paid to condition) that leaves your house, one cubic foot of outside air enters!

Looking for just one thing you can do to improve your home's energy efficiency? Significantly reduce air infiltration. Gaps or cracks in a building's exterior envelope of foundation, walls, roof, doors, windows, and especially "holes" in the attic floor can contribute to energy costs by allowing conditioned air to leak outside.

Most Common Sources of Air Infiltration:

  • Bypasses (attic access door, recessed lighting, plumbing stacks, dropped soffits, open frame construction, duct penetrations, electrical penetrations, etc.) in the attic floor regardless of the presence of insulation, which by itself is not an air barrier. If you see dirty insulation, air is getting through.
  • Between foundation and rim joist
  • Crawl spaces
  • Around the attic hatch
  • Between the chimney and drywall
  • Chimney flue
  • Electrical and gas service entrances
  • Cable TV and phone line service entrances
  • Window AC units
  • Mail chutes
  • Electric outlets
  • Outdoor water faucets entrances
  • Where dryer vents pass through walls
  • Under the garage door
  • Around door and window frames
  • Cracks in bricks, siding, stucco and the foundation
  • Mudrooms or breezeways adjacent to garages

Take action:

Drafts can also be reduced by simple measures such as:

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Heating and Cooling


It doesn't make any sense to upgrade your HVAC system if you haven't already done a comprehensive job of air sealing and adding insulation—these will reduce the heating load and allow for a smaller, less costly new system. Older homes with hydronic (radiator) heating typically have had to rely on window AC units for cooling. Today there are new options for cooling that do not require ductwork—these systems are called ductless mini-splits. These ductless mini splits can also provide heat via heat pump options.

More information on ductless mini splits>>

Similar to other energy efficiency improvement strategies for your home, there is no one-size-fits-all solution for upgrading mechanical systems in your older or historic home. Instead, a more holistic approach is recommended. One that is specific to your home or building, its use, and the needs of its occupants. Considering a combination of solutions and/or systems might also be the best solution. It may be necessary to think of your home as a collection of several systems working together, rather than a single system designed to maintain comfortable temperatures. Using a whole-house approach will save trouble and money in the long run.

Need help with your radiators?

The hot water heater is an energy intensive system in most homes—typically about 13 percent of your utility bill – reduce your bill with these low-cost actions:

Geothermal heat pumps, also known as ground source heat pumps, might also be an option to reduce heating and cooling costs.

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Simply adding insulation to the attic is one of the most cost-effective and energy efficient steps you can take. Yet always be sure to air seal the bypasses first. Not sure where these are? Dirty insulation is the tip off—where you see dirty insulation, air is passing through and the insulation is serving as an (unintended) air filter.

If you live in a historic house, you may find everything from corn cobs to newspaper to bricks in the walls for insulation. Fortunately, today there are higher performing options. If installed properly, the addition of insulation can reduce energy costs by as much as 50 percent in some cases and make your house more comfortable.

Because insulation may not have been included in your home originally, introducing insulation should be done carefully and with particular attention to ventilation. If insulation is installed without appropriate air sealing and ventilation, insulation can become damp, causing it to lose its effectiveness at preventing heat loss. Damp or wet insulation can also lead to mold growth or cause rot in framing or other wall components. This in turn can degrade indoor air quality and aggravate allergies.

Air sealing & insulating a few key places in historic structures—attic spaces, crawl spaces, basements, around heating/cooling ducts, and around water pipes—provides the greatest benefit with the lowest risk of damage. How much insulation do you need? That depends on where you live and where you plan to install the insulation. Using your zip code and some basic information about your home, the calculator function on the Oak Ridge National Lab's website can help get you started.

Walls: To insulate or not to insulate?

If your home dates to the 1850s or earlier and its frame is made of wood, there is a good chance that is has post and beam construction rather than balloon framing. This is an important consideration if you're thinking about adding insulation in the walls.

Without modern vapor barriers and insulation, air and moisture in the house moved more easily between inside and outside. Adding insulation to the wall cavities without understanding how the house functions as a system and without establishing new ways to circulate air through the home can cause moisture to accumulate. High moisture levels can result in mold and rot, creating serious problems for the homeowner as well as unnecessary expense.

Wall insulation can be problematic in historic structures as it is difficult to install properly due to the unpredictable nature of historic walls.

The trouble and expense of insulating historic walls may not be the best bang for your buck. Once you have air sealed and insulated your attic, tuned up (or replaced your furnace), and completed some of the higher priority energy saving techniques you might then consider insulating your walls but get advice from an expert. By undertaking these other energy-saving measures first, you may find that your comfort level goes up and your energy expenses go down significantly without the need to insulate the walls.

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Windows contribute a great deal to the look of your home, are important parts of your home's architectural history, and are often made from high-quality and valuable materials that are no longer available.

If your windows predate about 1950, the wood itself is likely to be valuable and now scarce old-growth wood, which is denser, more rot- and warp-resistant, and holds paint better than modern, plantation-grown wood. Additionally, if a component is damaged it can be repaired or replaced without having to replace the entire window. While historic windows have all of this going for them, they are often the first elements people look to change when trying to improve their home's energy efficiency. Fortunately, the decision to retain historic wood windows needn't get in the way of improving the efficiency of your home.

First, studies suggest that only about 10 to 15 percent of a home's energy is lost through its windows, The U.S. Department of Energy reports that windows can be responsible for up to 25 percent of your heating bill. For comparison, a hot water heater is typically responsible for about 13 percent of your utility expenses. Repairing older wood windows instead of replacing them can usually be done at a lower cost than replacing them, while achieving approximately the same level of energy efficiency. Even if an estimate to have your windows professionally repaired is in line with a new window, the end result will likely be a window that will last longer, therefore saving you money in the long run.


Conserving your historic windows also can be far better for the environment. By repairing and weatherizing your existing windows, you are keeping their valuable material out of landfills and new materials are not required to manufacture new windows.

The repair and weatherization of traditional windows can either be completed by a professional or by the homeowner. If completed by the homeowner, repairs can be done at a much lower cost, since most of the expense of window repair is derived from labor, not materials.

Advice on how to repair your wood windows:

Be aware that older homes (prior to 1978) may have lead paint. Before digging into repair projects, including window repairs, make sure to learn how to work lead safe:

The simplest ways to gain more energy efficiency from historic windows are to add weather stripping to the sash, make sure that the sash lock holds the meeting rails tightly together, and to caulk the window's interior and exterior casing to stop air leaks. For more information on how to select and install weatherstripping, see articles such as "Strips and Storms Windows: Techniques for tuning up sash windows for winter" Exit EPA Disclaimer in the Old House Journal.

Storm windows, which can be affixed to either the exterior or interior of a window, offer additional energy savings. Much like traditionally-constructed cavity walls, snugly fitted storm windows create a void that slows the transfer of heat. In contrast to double-glazing, this technique allows the original windows to remain intact, while providing added insulation and significantly reducing air infiltration.

Adding a storm window to a weather stripped historic window can achieve essentially the same, and sometimes better, energy performance as a new insulated dual-pane window. Besides providing thermal insulation, storm windows have the added benefit of providing sound insulation as well as protecting the original window from the elements.

For additional energy savings, noise reduction, and/or security, storm windows that use low-E or laminated glass are also an option. While these will cost more than standard glass, the energy saving and comfort may make it worth the added expense. A historic window with a low-E storm window has been shown to perform just as well as a replacement window. Laminated glass has excellent sound dampening qualities and its strength provides an extra measure of security.


If you live in a local historic district, be sure to check with the local historic district commission before purchasing low-E storm windows. If exterior storm windows don't comply with district guidelines due to the tinting, using an un-tinted version or an interior storm may be allowed.

A 2009 study commissioned by English Heritage found that using a low-E storm window reduced the amount of heat lost through the window by 58 percent. One consideration is that a low-E storm may make more sense in warmer climates than very cold climates. In cold climates, greater benefit may be achieved by allowing solar heat gain during the day rather than by limiting it, particularly in winter months. In some areas of the country, the advantage of solar heat gain can be significant, particularly if blinds, shutters, curtains, or shades are drawn when the sun sets to retain the heat. This does not mean that low-E storms aren't an option in cold climates. You might consider using the low-E glass for some elevations, but not on others. The same English Heritage study found that simply closing heavy curtains at night reduced heat loss by 41 percent, closing well-fitted interior wooden shutters reduced heat loss by 58 percent, and a honeycomb insulating shade reduced loss by 51 percent. Many of these insulating shades also qualify for a tax credit.

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Keeping an older or historic building in good condition does wonders for its energy efficiency. Regular, diligent monitoring of its condition—whether making sure windows and doors open and close as tightly as they should, or checking for (and sealing) gaps in masonry that might be causing drafts or letting in pests—can make a tremendous difference in your home's performance over time. Pay particular attention to ensure a sound water (rain) barrier. Water intrusion is the most common cause of house damage. Gutters, downspouts, flashing, chimney caps, and landscaping all contribute to moving bulk water away from the house. It will not make sense to seal and insulate an attic if faulty flashing is allowing water into the space.

A little time and effort every now and then can add up to a significant environmental benefits by keeping building materials out of landfills, not to mention a substantial financial savings for the homeowner.

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Helpful Tips & Resources

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Books on traditional construction and regional differences:

Online interactive guides:

Video - Common energy saving features of historic buildings:

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