I recently (a few months back) proposed to Allison Bailes of Energy Vanguard that we write a North vs. South energy audit article. It may yet come about (and hasn’t so far because I’m miserable at follow through) but it’s a worthwhile topic. Audits and the energy priorities they consider are very different based on climate zone and region: the housing stocks, the types of insulation used, mechanical systems and weatherization performed vary greatly. The issues and solutions are all different.
Audits in the North
Housing Stocks – In New England, the place is lousy with history. While buildings and the sites may not be Europe-old, they do span every era back to colonial times. Older homes are timber framed with heavy plaster walls and rubble foundations. The late population booms in the 19th century and early 20th century lead to loads of balloon framed homes along coastal Maine. The post-World War II baby boom filled entire neighborhoods with generic ranches, capes and colonials.
While there hasn’t been quite the suburban growth in Maine as in some other states, that is where most modern growth occurs. These pockets of manicured developments are mostly variations of colonials or other classic designs or neo-eclectic construction.
Insulation – The insulation situation in New England varies right along with the housing stock. Unlike more newly settled areas of the country, New Englanders can’t count on any consistent level, type or even presence of insulation.
In a modern suburb, even the most tossed together construction is insulated to building code, usually with either fiberglass or cellulose. In Maine and the rest of New England?…You have the entire spectrum of housing stock with a vast array of possible actions since it’s original construction. This is a theme we’ll return to a few more times.
For the auditor, this means exploring the wall cavity and attic is all the more important. Testing multiple points and each wall, scanning with an infrared camera and probing the wall cavity with a boroscope are all important tools. They can all help paint the full picture of the house’s thermal envelope.
Older homes can be uninsulated or have had some half-assed attempt to rectify the frigidly cold second floor bedroom. There may be loose-fill cellulose, dense packed cellulose, vermiculite, loose fiberglass, fiberglass batts, loose rock wool, open or closed cell spray. Damn.
Of particular note is the possibility of vermiculite insulation. It is very common in Maine and before its association with asbestos was known, it was used as an insulation for decades.
For a bit more detail, check out these articles on vermiculite and Zonolite-brand vermiculite. The shorthand upshot is that one mine in Libby, Montana produced vermiculite with asbestos in it. Asbestos isn’t always present in vermiculite (or even often) but it has become strongly associated with it.
This is an issue with blower door testing. The blower door’s powerful fans can easily disturb any potentially asbestos-laden vermiculite dust. Friable asbestos fibers could be blown all over the house…which is bad.
Heating Systems – Mechanical systems in the south serve multiple functions in the service of their warmer and more balanced climates. Virginia, for example, has very distinct heating and cooling seasons. Their mechanical systems follow suit, providing heating and cooling.
This most often means a heat pump system with ducting. This allows a single system to both heat and cool the entire house.
The northern states are more mono-climatic. There is heating season and strip down to a t-shirt season. The summers rarely get so hot that one needs dedicated air conditioning. It’s very nice but hardly essential. There’s also more oil heating than natural gas and by a wide margin more water boiler systems than hot air furnaces. This vary from state to state (for example, Maine has loads of oil heating, where Massachusetts has more natural gas) but are broadly true.
The sheer age of the housing stock affects the heating system choices much like with the insulation. Homeowners make a vast array of stabs at updating their older methods of heating. A two hundred year old house may pass through dozens of hands over the years. And those dozens of hands are attached to dozens of opinions as to how they ought to heat the house. So you find wood stoves, pellet stoves, fireplaces, fireplace inserts, boilers, furnaces, monitor heaters, space heaters of every stripe with the occasional ground source, air source heat pump or ductless split system sprinkled in for flavor. There are options.
Ventilation – Building ventilation is in the same dust up. Most buildings in the northeast were built prior to or during the introduction of ventilation standards to he building code. And the same homeowners who installed all those heating systems also jury-rigged ventilation. Perfect continuously vented soffits are rarely easily retrofit so we see the same vast array of attempts at ventilating.
The houses anywhere in the country would provide unique challenges and issues for the energy audit. The older houses of the New England northeast, haphazardly retrofit for our cold climate certainly provide their challenges.