Effective Strategies for High Performance Buildings (HPB) and Net Zero Buildings (NZB)
Most Significant Energy Improvement Opportunities are found in the following 4 techniques in this order.
1. Change the existing electrical loads to net metered solar power. Electricity's average cost in Ontario is about $.15/kWh. The lifetime cost of solar power (capital cost/lifetime energy production) is $.08/kWh.
2. Implement Conservation Measures - Provide insulation and air sealing where low levels occur and replace poorly performing components (windows, lighting, appliances, etc.) with higher performance units at the end of their lives. Also, consider energy recovery from sewage and exhaust air streams.
4 . Heat Pumps - In Canadian and Northern US Climes, heat pumps lower a building’s annual heating energy consumption by approximately 60%. In other words heat pumps can create 2.3 kW or more of heat for every kW of electricity supplied. Heat pumps can be used for Domestic Hot Water and Space heating, These heating loads in northern climes are generally 80% or more of a building's energy load.
4. Solar Panels - Once the natural gas fuel supplies have been switched to electricity then offset this energy with Net Metered Solar Power. Natural gas costs about $.055/kWh (when the equipment cost is included in the operating cost). However combine the excellent COP (Coefficient of Performance) of heat pumps with the lower cost of solar power and heating costs drop below the cost of heating with natural gas (~$.050/kWh) and produce no Green House Gas (GHG) emissions unlike Natural Gas. A typical natural gas heated 2,000 sq ft house in Ottawa produces 6.0 tons of GHG emissions annually. NZBs eliminate these GHGs. For reference a typical gasoline powered car produces 5 tons of GHG emissions annually.
Net Zero Energy Building Planning - Net Zero Energy means the building produces as much energy as it uses in a year. Most buildings can be economically modified to be a Net Zero (energy) Building (NZB). We can create a plan to move your building (house or larger building) economically to Net Zero by identifying when the above components (and others) in your building or house can be economically replaced with newer more sustainable equipment. Mostly this happens after the older technology equipment requires replacement (like when your furnace, boiler or AC units have reached their end of their life or it can be immediately like installing insulation, air sealing or solar panels to offset your existing annual electricity needs. We identify the economical replacement equipment or components and provide a plan for you to incrementally move your building to a Net Zero Energy requirement powered by renewable energy.
Order Matters - In general the formula is to switch the existing electrical loads to net metered solar, then "do the easy conservation measures (insulation, air sealing, heat recovery). Next, switch the space and DHW heating to heat pump heating. Finally additional net metered solar power to move the space and domestic hot water heat to higher efficiency heat pump supplied energy.
When do you Replace your Older Technology building components? Make a plan to do various Energy Conservation Measures at about 3/4s of their life (for instance your furnace has a life of about 20 years, so replace it at 15 years). Why? Energy savings are generally not so significant that there are good paybacks if including the residual value of the component. This way your costs are mostly only the incremental costs over the older technology. Also costs are a reasonable proxy for embedded energy. Retire a component early and you're also retiring embedded energy. Why 3/4 and not fully depreciated? Because if you try to run to failure, that of course will happen and you'll be replacing the component under duress (i.e. a new furnace in January) and have to buy whatever the contractor has in the warehouse. Invariable it will be the traditional (likely fossil fuel version) you'll have to install the sub-optimal component and be locked into that for the next life cycle."As part of our plans we determine the age of your components (eg. windows) and appliances (eg, AC unit, furnace and DHW heater) and recommend a year to replace these.
Why not just get an NRCan energy audit? The NRCan energy audit is a very valuable approach to energy conservation but it has some limitations our report corrects. The NRCan energy audits give the end uses of your homes energy in Giga Joules (GJ) by component (walls, windows, etc.) and usage (space heating, DHW, AC, etc.). It also gives a list of recommended Energy Conservation Measures (ECMs) in GJs. and shows how much energy reduction can be achieved. We convert these GJ estimates to dollars to give you measurements in terms that are meaningful to you (dollars vs, GJ). We also estimate the costs to do these ECMs (for your budgeting) and give you the payback in years to pay off each measure. Also we identify the Green House Gas reduction of each measure to allow you to determine the relative importance of each measure you do to reduce your GHG footprint. Finally, recommend the year you should do each measure to match the retirement date of each component (for instance we recommend replacing a furnace after year 15 years and moving to the non polluting less expensive heat pump and solar panel combination).
See our fees webpage for Net Zero Planning Costs.