Designers of energy-efficient homes — especially homes aiming for net-zero energy use — must inevitably grapple with the question of simplicity versus complexity.
Residential designers can choose from an array of sophisticated appliances that improve comfort and help homeowners reduce energy use. Examples include heat-recovery ventilators (HRVs), condensing boilers, ground-source heat pumps, solar hot water systems, on-demand water heaters, heat-pump water heaters, photovoltaic modules, and co-generation systems.
Most of these devices perform well. However, designers who specify sophisticated appliances need to consider the trade-offs that accompany such hardware:
Builders often underestimate the importance of commissioning all HVAC equipment after installation. (“Commissioning” simply means making final adjustments and tuning up equipment to verify that it functions properly.)
Unfortunately, most new homes are imperfectly commissioned, leading to one or more of the following errors:
HVAC commissioning errors almost always result in needless increases in energy costs. Many HVAC specialists can share horror stories about commissioning errors, running the gamut from irritating to outrageous (for example, air-source heat pumps with electric resistance elements that operate for most of the winter).
For four years in the 1990s, I provided capital needs assessments — glorified home inspections — for multi-family residential projects in Vermont. During that time, I inspected hundreds of residential buildings maintained by professional management companies.
Almost all of the buildings showed signs of neglected maintenance. Among the problems I saw:
There’s no reason to believe that American homeowners are any better at maintenance than the average residential property management company; in fact, they may well be worse. That’s why anyone involved with home inspections can share stories similar to mine.
Many of today’s harried homeowners don’t even know where all of their mechanical equipment is located, much less the equipments’ maintenance requirements.
Even well intentioned homeowners sometimes decide that it makes economic…