Ralph's Energy Efficiency
Saving energy and saving money.
Sunday, January 19, 2025
NSPower installing 180kW EV chargers in 23 locations
Saturday, November 11, 2023
The Canada Greener Homes Grant likely won't end in March 2024
The Greener Homes Grant provides homeowners with up to $5,000 in rebates for energy efficient upgrades. Shortly after it was announced in 2021, NRCan received tens of thousands of applications, and wait times for an energy assessment grew to several months. As someone who enjoys sharing my knowledge and experience, I decided to obtain a license from NRCan to do home energy assessments.
The program funding is $2.6 billion, which was initially expected to last until 2027. However due to the popularity of the program, and due to the amount of the average grant being higher than expected, the program may end in March 2024. This was announced by NRCan on 2023-11-09 during a service organization town hall meeting.
Anyone who gets an initial energy assessment done before the program end date will still be eligible for the grant. I think it's possible, and even likely, that additional funding will be provided to the program. Whether that funding comes before March, and whether the grant amounts will remain the same, is more questionable.
Instructions for how to find a service organization and book an energy assessment are on the Greener Homes Grant site.
2023-12-09 Update:
I contacted my MP, Kody Blois, and he called me back to discuss the Greener Homes Grant. He said climate change initiatives continue to be a top priority for the Liberal government. Kody said he spoke with Jonathan Wilkinson, Minister of Energy and Natural Resources. Kody said Minister Wilkinson confirmed they will "recapitalize" the Greener Homes grant.
Sunday, August 20, 2023
Solar PV 101
In most parts of Canada, with the benefit of the Greener Homes Grant, the payback period is less than 10 years. And with the Greener Homes Loan, homeowners with good credit can get 0% financing for the full cost net of rebates.
A single solar panel will produce 400 to 600 Watts of power when facing the sun on a clear day. For comparison, a microwave running on full power consumes about 1200 watts. Inverters convert the direct current power from the panels to 120/240 volt alternating current used in the house. Most homes would need at least 20 panels to provide for all of their power needs, though there may not be enough room on a southerly-exposed roof for that many panels.
Since batteries are costly, most homeowners will set up net metering with their power utility. The inverters will send unused power on sunny days to the grid, and the homeowner will get credit to use that power at a later time. A reasonably-priced 5000 watt system will cost around $13,000, while a 10,000 watt system will cost around $22,000. Considering the time required for electrical permits and inspections, system installation time is about two months.
Solar system prices over the long term have been dropping, however the global chip shortage and shipping backlogs caused prices to increase during 2021 and 2022. Prices have started to come back down, and system costs will likely reach a new low in 2024.
Tuesday, February 21, 2023
Gas and Electric Car CO2 Emissions in Nova Scotia
Electric vehicles are often referred to as zero-emission vehicles, however that's a bit misleading when the electricity comes from burning oil and coal. In places like British Columbia and Quebec, where most generation is hydroelectric, EV emissions are close to zero. Considering coal still plays a large part in in the Nova Scotia generation mix, I decided to compare the CO2 emissions of gas and electric cars.
According to NSPower 2021 reporting, each kWh of electricity produced results in 603 grams of CO2 emissions. Canada's most popular electric cars are the Tesla models 3 and Y, the Ford Mach-E, and the Hyundai models Kona and Ioniq 5. According to NRCan, it takes an average of 18 kWh of electricity to drive these vehicles 100 km. Since EV chargers and batteries are not 100% efficient, about 10 to 15% of the grid power will be wasted as heat. Assuming 12% losses, the CO2 emissions can be calculated as:
18 kWh/100km * .6 kg CO2 per kWh * 1.12 loss factor = 12.1 kg/100km
Referring again to NRCan, the average new car with a gasoline engine has a fuel efficiency of 8 L/100km. Burning 1L of gasoline produces 2.3 kg of CO2, so the CO2 emissions can be calculated as:
8 L/100km * 2.3 kg/L = 18.4 kg/100km
This means a gas-power car produces about 50% more CO2 than an electric car charged from the NS grid. Nova Scotia is slowly reducing the amount of oil and coal used for power generation. If you don't want to wait, the quick way to get to zero emissions is to install solar PV panels to generate enough power to charge your vehicle.
Thursday, December 29, 2022
Solar PV costs should drop in 2023
Monday, February 19, 2018
2018 heating costs in Nova Scotia
This year I created a spreadsheet to make it easy to recalculate heating costs. The cost of heating oil is up about 20c/L, and prices for wood pellets have dropped from around $6/bag to $5-$5.50/bag, making pellets a much cheaper source of heat than oil.
For heat pumps with an average COP of 2.0, heating costs are slightly higher than pellets. A high-efficiency ductless heat pump purchased in the last few years will often have an average heating season COP of around 2.5, making the cost for 1000 BTUs of heat around 1.8c. While that price might seem good to people in Eastern Canada, it's very expensive when compared to the cost of heating with natural gas in Alberta. Delivered prices after taxes for residential dwellings is under $5/GJ, making the cost for 1000 BTUs of heat around half a penny!
The outlook for Alberta is that cheap natural gas prices will continue for years to come. While we on the East coast may laugh at Albertans having to endure bitter cold compared our milder winters, they'll have the last laugh when their heating bill comes.
Tuesday, December 19, 2017
HRV? You need one like you need a hole in the wall.
An air-to-air heat recovery ventilator (HRV) can be found in most Canadian houses built in the last 10 years. The theory behind their use is that natural air ventilation rates are not sufficient for good indoor air quality, and an air exchanger without heat recovery wastes energy. Although the second part is true, the first part is not. HRVs add $1,500-$2,000 to the cost of a new home, and are often a source of additional heat loss, even when not in use.
For many years I've been saying air tightness is of utmost importance in homes. According to research done in 2007, Canadian homes built after 1991 had an average air tightness of 3.6ACH@50Pa. Even with improved construction practices in the past ten years, most new homes being built in Canada today would be better off without a HRV. Most new houses have enough natural air ventilation to maintain good air quality during the coldest parts of winter. Many actually have too much natural ventilation, causing unhealthy low levels of humidity. The supposed need for HRVs is based on the ventilation rates in CSA standard F326. The ventilation levels in F326 seem to be based on bad assumptions and wide margins of error, rather than basic science. That's despite the fact that NRCan published reports analyzing indoor ventilation requirements as far back as 1969.
What I find a bit surprising is that building engineers are aware of this issue. Several years ago a senior ASHRAE member told me, "It is widely acknowledged that continuously ventilating houses at F326 rates can results in the houses being over ventilated". Perhaps what is not as widely known is that even "tight" houses with air infiltration rates of 2ACH@50Pa will have high enough natural ventilation rates during the coldest parts of winter. This is not just based on theory, but also indoor CO2 and humidity testing done by myself and others.
I suspect this is not a concern for most people in the HVAC industry since homeowners can just turn off their HRV in the winter. Besides the unnecessary cost of the HRV, what that ignores is the heating loss from a HRV, even when it is turned off. The ducts installed for the HRV often go in and out of attic spaces, which are sources of air leakage unless they are perfectly sealed. Standard HRV designs use only a single damper to block off either the exhaust or fresh air intake when the HRV is not running. This means the HRV adds a six-inch unobstructed hole to the building penetrations. A thermal infrared scan I recently performed clearly shows the heat loss from an exterior HRV duct.
Since removing HRVs is not a viable option, homeowners should at least turn them off during the winter. To avoid heat loss through the outside vents, I tape over the hood opening. I might even leave the vents taped off all year long, and just use a bathroom exhaust fan. Although I'll loose the benefit of heat recovery, when the outside temperature is only 10-15C different than the inside, that heat loss rather modest.