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 500 Watts of power in bright sunlight.  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


In 2022, Solar PV costs reversed the long-term trend of lower costs.  Higher shipping costs played a part, but supply unable to keep up with strong demand growth was the main factor.  In Canada, wholesale prices of PV panels were up about 25% from 2021.  Inverter prices were up, and availability was impacted by the semiconductor shortage.  The outlook for 2023 looks much better.

Shipping costs started dropping early this year.  According to Freightos, costs as of 2022-12-23 are less than a fifth of what they were a year ago.  Port delays have all but disappeared, so products are arriving in a timely fashion.  In 2023, freight costs should be $5 to $6 of the landed cost of PV panels.

Inverter prices won't be dropping much in 2023, as the supply of power semiconductors is still tight.  Electric vehicles use some of the same semiconductors as inverters, so the demand for EVs will continue to support power semiconductor prices.  As new technologies such as gallium nitride are incorporated in PV inverters, size and costs will go down.

Throughout 2022, prices of polysilicon have held at around triple their pre-COVID levels.  Polysilicon is the primary ingredient in solar cells, so those prices have a large impact on the price of PV panels. Prices have stayed high despite expanding capacity from China's polysilicon manufacturers.  However just before Christmas, PVinsights reported dropping polysilicon, wafer, and PV cell prices.  On December 23, LONGi announced a price drop of almost 30% for PV wafers, from 7.42 Yuan to 5.40 Yuan.

Module price drops should follow the drop in polysilicon, wafer, and cell prices.  Polysilicon ingots are cut into wafers, which are then processed into PV cells.  The cells are then soldered or welded together and assembled into modules.  The cost of cells makes up more than half the cost of the module, so lower cell prices will lead to lower module prices as inventories of cells are replenished.

By summer 2023, I expect wholesale PV panel prices to drop to 40c per watt, about where they were two years ago.  Inverter prices will likely hold close to their current levels, which is around $200 for a dual micro-inverter, and about $1,200 for a 4 kW string inverter.  Although customers will not see much change in prices for installed PV systems, they should no longer experience long delays waiting for panels or inverters.

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.

Sunday, April 2, 2017

Sizing and pricing a ductless split heat pump


It's been over two years since I first wrote about mini-split heat pumps.  In that post I explained a bit about how to size a heat pump, and now I'll go into more detail.  Most installers will use rather unscientific rules of thumb, so I suggest doing the calculations to get a more accurate estimate of your heating needs.  Also, the biggest benefit in heating cost stavings comes from installing one system.  When two systems are installed, the second system will rarely provide the same amount of savings as the first.  If the first system saves you $800 per year in heating costs, adding a second might only save you $400 more.

I've shown a power usage report for a house in Nova Scotia with electric resistance heating and no air conditioning.  Other utility companies should provide similar information with their billing.  The report shows that minimum daily use is 15-16kWh per day.  This would be power use from the electric hot water heater, household appliances, and lights.  Subtracting this from the wintertime peak of 122kWh per day gives 106kWh per day of electricity demand related to heating.  Since 1kWh = 3412 BTU, the house requires 106 * 3412 / 24hr = 15070 BTU/hr of heating.  The house will have some upgrades done such as additional attic insulation and air sealing, so the average January heating demand will be less than 15,000 BTU/hr.  The layout of the subject house is reasonably open, so single ductless split with a heating capacity of one ton (12,000 BTU/hr) at -15C will probably be able to provide more than half of the heating requirements.

One-ton mini-splits appear to be the most popular units for residential installs in Nova Scotia, with 1.5 ton the next most popular.  Installed prices for a top brand name (Fujitsu, LG, Mitsubishi) one-ton unit are typically between CAD $3,000 and $4,000 plus sales tax.  For the subject house the installation is rather simple, with a short vertical run for the line set from the outside unit to the inside air handler.  After searching ads on kijiji and asking for referrals, I obtained a quote for CAD $3000 + tax to install a LG LA120HYV system.  It has a maximum heating capacity of 13,720 BTU at -15C and 15,650 BTU at 0C, requiring 1.57kW of power for a COP of 2.92.  This means the cost of one BTU from the heat pump is about one third of the cost of one BTU from an electric resistance heater.  With electricity costs of 15c/kWh in Nova Scotia, I estimate the LA120HYV system will save $1,500 per year.

While installed prices for a top brand heat pump generally start at $3000 and they are usually only sold as installed packages, systems from Chinese manufacturers Gree and Midea can be found for under $1000.  If was buying for my own home where I could install and maintain the system, I'd choose a much cheaper (lower-efficiency) Midea system.  For example, a nominal one-ton Rheem-branded mini-split system manufactured by Midea sells for $799 at my local Home Depot.

I'll note that making technical comparisons of mini-split heat pumps is a very difficult process.  Finding engineering manuals for cheap systems from Midea is almost impossible.  For the high-end brands, despite marketing about their quality and efficiency, many don't publish the engineering data on their web sites to back up those claims.  Between Fujitsu, LG, and Mitsubishi, LG is the only one (as far as I could tell) that makes their engineering manuals readily available on their web site.  For Fujitsu, I had to call their technical support to request an engineering manual for their RLS3 series.  A local Fujitsu dealer I spoke to justified the higher prices of the Fujitsu units by claiming they are more efficient than LG, but he didn't have any numbers to back up the claim.  The specs on the LA120HYV1 show that it is slightly more efficient than the Fujitsu 9RLS3.  The Fujitsu does have a bit higher output than the LG (15.4 vs 13.7k BTU @ 5F), so at 13.7k BTU of output the Fujitsu might  be a bit more efficient.  Given the installed cost of the LG is much less than the Fujitsu, I think the certainly of lower capital costs trumps the possibility of slightly lower operating costs.

If you are doing your own comparisons, take note of the difference between the actual and rated (advertised) capacities.  Industry standards require that a heat pump advertised as a 12,000 BTU model must be able to output at least 12,000 BTU at an outdoor temperature of 47F (8.3C).  System's like Fujitsu's RLS3 series and LG's HYV1 will output much more than their rated capacity, and even output their rated capacity down to -15C or colder.  LG's lower-cost  HSV4 series however only outputs 69% of their rated capacity at -15C.

Addendum - beyond the numbers

Avoid installing too much capacity, such as putting two 1.5 ton systems in a small house (something I have seen in my own neighborhood).  Modern split heat pump systems are variable capacity, meaning they will reduce their heat output before they shut off.  A system that has an output of 16,000 BTU at 0C may reduce it's output to 8,000 BTU before shutting off.  However if it only stays on for 15-20 minutes before turning off, and then turns back on 5 minutes later, it might never enter a defrost cycle.  Depending on how intelligent the controls are, this may not be a problem for some units, but I have heard of this happening with Daikin, Fujitsu, and LG units.

In snowy climates the outdoor units should be sheltered from blowing snow, or raised high off the ground.  When snow blocks the fan blades on the compressor unit, it can blow a fuse on the fan controller board, or fry the control board if it has no fuse.