HERITAGE GOES GREEN
Upgrading Your Heritage Home
Tips for Conserving Energy
Engineering co-op student Mike Mutrie has just completed an investigation for the Heritage Branch of the traditionally-constructed residential building envelope. ?Mutrie’s findings support what many have known for years: traditional building ?assemblies that breathe (transpire) require a different approach from modern ones that are sealed and need assistance to breathe. Further, new technologies offer a relatively pain-free way to improve the performance of old building envelopes. ?His findings provide a useful departure point for owners wishing to retain the ?character of their homes while improving their energy performance. For a typical 1913 traditionally-constructed wood frame home:
- Ask a certified energy advisor to show you how your home is performing using a blower door test. This is a very effective way, at modest expense, to visualise air leakage.
- Seal the worst leaks – this does not mean going berserk with a caulking gun. Repair fissures and gaps in a way that is complementary to existing finishes and that will have a long life expectancy. Close fireplace dampers when not in use.
- Insulate uninsulated walls – we read a number of positive reviews of blown ?cellulose (recycled newsprint) incorporating a borax additive, that does not slump within the wall cavity like some predecessor products.
- Insulate the attic at ceiling level, and, when re-roofing, insulate otherwise ?inaccessible cathedral roof structures over dormers by removing sheathing or blowing in insulation.
- Ideally, overhaul (ease, strip, repaint, replace cords, wax sash grooves, weather-strip etc.) windows at the same time as insulating the wall and augment them with interior or exterior storms. In this way the improvement of the R value of the envelope is consistent across the wall assembly and does not lead to temperature differences at window wall junctions that can cause condensation and mould.
- Do not incorporate a vapour barrier. Interior moisture vapour is generally inhibited from entering the walls by layers of paint. Moisture entering from the exterior tends to dry out by itself through evaporation and convection (that’s why these buildings have been around so long …).
- Avoid mixing building components made for sealed building envelopes (such as modern plastic and aluminium replacement windows) with traditional building envelopes. The effects on moisture movement at the boundary of the two can be unpredictable, and in some regions have been shown to accelerate decay of the building envelope.
- Purchase a lagging kit (an insulating cloak) for your hot water tank.
- New energy-efficient domestic heating and hot water systems are both cost-?effective (they have short payback periods) and can be retrofitted without damaging the special character of your home.
- Particularly in coastal BC, an air-source heat pump can be used to heat air for distribution through an existing ducted air system or to heat water for radiators. In colder climes, a ground source heat pump for heating may be the right choice
- Consider going to an electric, gas or propane tankless hot water system
- Retrieve waste heat from your soil and vent pipe with a heat exchanger
- Seek federal government grants for these technologies.
For tips on conserving heritage windows
» Upgrading Windows
For current news articles about Sustainability
» News : Sustainability
BY RICHARD LINZEY, SENIOR HERITAGE PLANNER, BC HERITAGE BRANCH
FROM HBC QUARTERLY SPRING 2008