A Slightly Greener Home
We received the final report for our greener homes grant audit today.
It's sort of like getting a report card for a project you've been working on for over a year, and we were eager to see whether the time and money we poured into making the house more efficient was worth it and whether our own calculations matched up with the audit. We've not been approved for the $5,000 Canada Greener Homes Grant yet but I don't believe we'll run into any problems.
Our home was built in the early nineties and is a walk-out bungalow with 1178ft² of conditioned space on the main floor and 1133ft² in the basement. There are currently four adults and two toddlers living here as we rent half the house to another family.
The biggest upgrade we made was the 7.65kW solar system we had installed last March. Originally we had planned a system half the size but decided that because our furnace needed replacing anyway we could get a heat pump and use a larger solar system to help power it instead.
Our old gas furnace was an inefficient single-stage noisy beast that needed repair so we decided instead to put in a 2-ton Daikin DZ17VSA FIT Heat Pump and a high-efficiency 60BTU Daikin DM97MC Furnace for auxiliary heat. The comfort level of the house is night-and-day compared to before and in a lot of ways these upgrades were worth it in their own right.
Our 40gal hot water tank is still in good working condition still so we haven't done anything with this yet.
The windows in the house were original double-pane sliding windows whose seals had completely failed so we had a ton of condensation problems when it got cold outside. We replaced nearly all of them with triple-pane hinged windows that seal up much better and haven't given us any condensation problems so far.
We also had the attic sealed up and the insulation doubled to help retain more heat on the main level.
Here's a rough comparison of the highlights from the auditing reports:
Overall Consumption
| Measure | Pre-Upgrade | Post-Upgrade |
|---|---|---|
| Energuide Rating | 131 GJ/y | 34 GJ/y |
| Natural Gas Consumption | 105 GJ/y | 39 GJ/y |
| Electricity Consumption | 7433 kWh/y | 10287 kWh/y |
| Electricity Production (Solar) | 0 kWh/y | 11673 kWh/y |
| Natural Gas Emissions | 5.4 T/y | 2.0 T/y |
| Electricity Emissions | 6.0 T/y | 8.3 T/y |
| Electricity Offset Emissions | 0.0 T/y | -8.3 T/y |
| Comparison to new house | 29.7% more energy | 26.2% less energy |
The emissions changes are the most important to us as we went from a net 11.4T/y down to 2.0T/y for our household energy.
That said, while the natural gas consumption appears spot on our electricity consumption and production are more around 8000kWh/y and I don't know how these numbers were arrived at. Our auditor is pretty busy and hasn't been quick with getting back to our questions but I'll update this if they do.
How Energy Is Used
| Measure | Pre-Upgrade | Post-Upgrade |
|---|---|---|
| Space Heating | 60% | 30% |
| Space Cooling | 0% | 2% |
| Water Heating | 20% | 35% |
| Ventilation | 0% | 0% |
| Lights and Appliances | 9% | 15% |
| Other electrical | 11% | 18% |
As we hoped, our space heating energy became a much less substantial part of our energy usage. Based on these numbers, our water heating is likely the next project to get optimized. Our 100 amp panel can't handle much more load, but an on-demand gas heater would likely help cut usage down quite a bit.
Where Our Home Loses Heat
| Location | Pre-Upgrade | Post-Upgrade |
|---|---|---|
| Attic/Ceiling | 12% | 8% |
| Main Walls | 17% | 21% |
| Exposed Floors | 0% | 1% |
| Windows | 26% | 18% |
| Exterior doors | 2% | 3% |
| Basement/Foundation | 27% | 33% |
| Air Leakage/Ventilation | 16% | 16% |
While the attic heat loss saw a drop, the leakage through the walls and basement have become more pronounced. Since the upstairs and basement are fully developed there's not much we can do without doing a major renovation so we're probably just going to keep trying to optimize the air leakage.