There is no shortage of advice for making existing houses more energy efficient. Much of the advice comes from folks who sell services and equipment, so skepticism is appropriate – some investments make way more sense than others.
While it is tempting to consider major changes like windows, new heating and cooling systems and any number of gadgets, the largest savings may occur by simply managing energy consumption.
There is, however no argument about changing lamp types, watching your plug loads, monitoring your thermostat more closely, making judicious investments in the house’s exterior surfaces, and seizing maintenance activities like boiler and water heater replacement as a way to improve performance.
Many suggestions are sensible and free – like a recent one I saw advised using a heavy comforter with space heating savings from reducing nighttime temperatures (and opening windows to improve winter air quality). Simple measures often have the shortest pay back!
First, though – knowledge is power, and you need to establish baselines for energy and water use so you can measure your improvements. Most houses in our region air condition with electricity and heat with gas. By isolating summer loads for gas, and winter loads for electricity, you can understand your space heating costs separate from everything else. Water, of course, is easier. Do this for a year so you’ll better understand your starting points.
It is interesting to note, by the way, that actual energy costs are just a little more than half of each utility’s bill – distribution charges are big, and are proportional to use, but there are a lot of taxes and fees – many of them mysterious – which are constant regardless of use. So concentrate on the basic costs.
Then a home energy audit makes sense, and you will be smarter about analyzing the recommendations.
Improving the building enclosure, or envelope is high on any list of fundamental improvements, while often also being the most expensive. Adding attic insulation is typically easy and inexpensive, while increasing insulation to the frequently uninsulated or underinsulated walls of older houses is the most difficult and expensive.
Window replacement is the most energetically marketed possible improvement, but can cost $500 to $1000 and more per opening, and has a very long payback. Cheap windows are no bargain – vinyl can yellow with age and energy savings are usually overstated by suppliers.
Greening your house may or may not add to its resale value. If you have any plans to move, any improvement should be measured against the market’s interest in green-ness – ask a real estate agent. Such interest is, at the moment, minimal in most markets, including the Washington-Baltimore region.
So green up – but measure your costs and benefits.
– Ralph Bennett, Principal