Establish the owner’s goals
The project team’s first task is to collaborate with the owner to establish the project goals. While these goals may evolve during the project, it is essential to inform the owner about the various possibilities to ensure that opportunities for co-benefits are not missed. These objectives may include:
- Reducing operating energy costs and emissions
- Securing energy cost stability
- Achieving net-zero performance and GHG savings, either immediately or at a later stage
- Lowering the long-term total cost of ownership
- Renewing the exterior, giving new life to an old building
- Increasing resale value
- Improving air quality and comfort
- Minimizing upfront carbon emissions during the retrofit
- Enhancing durability, leading to reduced future maintenance
- Addressing current or looming maintenance issues
- Adding amenity improvements that can be more cost-effective when included with the retrofit work, or which might be more difficult to implement after the retrofit
Evaluate the building
An energy audit and building assessment are required to dial in the best long-term net-zero version of that building that meets the owner’s goals and budget, and takes advantage of the opportunity to remedy existing problems.
Energy audit
The energy audit evaluates where energy is currently going — much is going out (or, in summer, coming in) through the walls, roof, windows, floors, air leakage and so on.
The energy audit establishes a benchmark and a breakdown so that the benefits and cost-effectiveness of possible improvements can be evaluated. Most energy modelling systems will work.
For single-family homes, an EnerGuide evaluation by an NRCAN-accredited Energy Auditor (EAs) using HOT2000 makes the most sense. This has the advantage that most utilities and municipalities require both before-and-after EnerGuide evaluations to qualify for subsidies and incentives. (See ‘Qualifications to look for in a project team’ above) In most cases, the EA is a member of the project team. If not, it is possible to work from an EnerGuide evaluation report.
Where possible, compare the energy model with the utility bills and calibrate the model accordingly.
Multifamily projects with 12 or fewer units per building can be modelled in HOT2000 as long as the EA has the necessary experience.
For larger multi-family projects, IES, Energy Plus, PHPP, Trane Trace or other ASHRAE-approved energy modelling software will be needed.
Building assessment
The objectives of the building assessment are to:
- Identify the structural condition and resilience of the building and identify issues that might compromise its long-term use and viability, e.g., foundation problems.
- Determine the maintenance and replacement work that the building needs or will need to keep it in good shape. The assessment should include an estimate of the useful remaining life of the major envelope components. These are independent of any energy upgrades but may present opportunities to solve several problems at once.
- Identify any code violations that need to be rectified.
- Identify any indoor air quality or other health concerns that need to be addressed.
- Identify issues of resilience — exposure to evolving climate risks like overheating, wildfire, flooding, and high-intensity storms — and opportunities the retrofit may present for mitigation.
- Identify utility capacity for electrification.
- Identify renewable energy potential.
- Find opportunities for the easiest upgrades for that particular building, considering how it is built and what it needs. For example, if the building has a trussed roof with low heels where the ability of the trusses to carry more weight is unknown, the retrofit solutions for airtightness and additional insulation may be limited to ‘flash and batt’ or a scissor truss roof over.
- Start to determine the most reasonable retrofit type for that building. Information gathered during the building assessment can narrow the range of retrofit options teams need to consider.
The person doing the assessment should be able to identify structural, durability and building science issues and have a pretty good idea of what to do about them. This professional should also have the ability to deduce the likely construction assemblies based on the age of the building and evidence of previous renovations. Finally, they will need to have a good idea of the costs and practicality of various solutions.
This assessment needs to include a review of any construction drawings or previous renovation drawings and any previous condition reports that might be available. Home inspection reports of the type usually done for real estate transactions can be a valuable source of much of the required information.
Taking lots of photographs during the walk-through will be immensely useful later. Whole-house 3D scans like those done with Matterport scanners are becoming more affordable and can save time and extra trips back to the site during the planning and drawing process.
There is some overlap in the information gathering required for the energy audit and the building condition assessment. While both need many of the same measurements and observations, most energy auditors lack the knowledge and experience to evaluate the condition of the building and its long-term maintenance needs or to identify the best opportunities for upgrades. They also lack the experience to estimate the relative costs of energy upgrades and remediation that might be needed. An experienced retrofitter or retrofit coach who can do both will save time and expense.
Consult the Retrofit Repository
The Retrofit Repository can help less experienced teams by showing what strategies and measures have been used successfully on other projects. As the library grows, the chances of finding a project similar to yours will increase.
