My Grid tied Solar

[justwork]

Hi people,

I'm looking at installing a 8.5kW grid tied solar system for my home.

Full disclosure, I'm Canadian. Canada has likely the worst rebate/credit available for residential systems. Likely I'll get $0.20 - $0.30 rebate per watt. So somewhere close to $2000 in rebate.

The panels I'll likely go with are a Canadian Solar 330 watt panel, which I can get for a pretty good price - around $5300 USD for 8.5KW

I'm looking at either the NEP BDM-250 Micro inverter OR the Enphase M250. NEP has better support in my location as a few installers carry their product so support and warranty claims may be better as a result.

From what I understand if I go with the NEP or Enphase micro inverter I'll need one per panel which would work out to approximately $4300 USD. To help with cost I've also been looking at the NEP BDM-600D which is a dual inverter, can put two panels on one inverter and daisy chain the inverters together. I can do 7 devices (14 panels) per 20Amp circuit. One string would have 12 panels and 6 BDM-600's and the other would have 14 panels and 7 BDM-600's. The cost of 13 BDM-600's would be slightly less then the 26 micro inverters at $3850 USD.

So for just panels and inverters, if I go with the BDM-600 my total taxes in would be $9150 USD.

I'm also looking at doing a ground rack system but have no clue where to start with that. Lots of sites but it seems like each piece needs to be ordered individually. I'd like to do screw piles for a foundation. Then run the two AC lines underground to my panel in the house. The run would be about 100 feet.

What foot print could I expect from a 26 panel ground mount array?
My total budget for this build is $13000 USD. I will pull permits obviously, do all the work I can do and have a licensed electrician do what they MUST do for the permit. I'l also need an inspection before the system can be turned on and a new net meter installed on my house by the utility company. I'm expecting $1500 USD for permits, inspections and the electrician doing what they need to do. Then likely $2000 USD for a rack. That gets me close to my $13000 USD budget. This is before cables, housing, electrical panels, and all the other things that add up quickly.

Advice? Tips? Tricks?

The other thing is this is a horrible investment where I live. The net metering program offers credits for the surplus power generated however, say in one month I generate 1kwh and consume 1kwh for a net of 0, I still pay tax on the 1kwh I used even though it was completely offset by the power credited to the grid. Any excess credit come March 1 just go to 0 - which I wont have to worry about since I will never produce more in 1 month then consumed. I'm also worried about how this will affect my property value, unlike most I do not want to see an increase in value as I plan to not sell my home any time soon and I don't want my property taxes to increase. Also, I have a big family, my wife and I plus 3 kids and 2 foster children. We also have a big house (for Canada) the total finished living space is 4500 SQF and including our unfinished basement we are close to 6600sqf. We also have 2 forced air electric furnaces that are 15,000 Watts each and two large heat pumps. It's cold in Canada and when the temps hit -16C the heat pumps shut down and the furnace kicks in. in 2019 we consumed 45,000 KWH which cost $4500 USD, I'm hoping to see this system get $1200USD in annual credit. The ROI is terrible at likely close to 10 years. However I'm optimistic that electric prices will only rise and the offset would be greater at that point. Plus I'm looking at ways to get our monthly expenses as low as possible and while it's likely going to only be around $100 less a month for power it's still $100 less.

I've already done most of what I can do to get our electric bill reduced. I've changed all the lights over to LED. I put motion switches in our kids bedroom, basement and garage so when the lights are left on they will turn off when no one is in the room. Our HVAC is serviced regularly and runs as it should. I've looked at switching out hatter and furnace to natural gas vs the electric system we have but the cost associated with running a line to the house and converting and replacing furnaces and water tanks is far to much - especially when the furnaces and water heater work just fine now. I'm looking at changing our cooktop to propane. Any other tips for reducing consumption?

Thanks in advance.

 

[maxx123]

how far are you from the border, I purchased used from Suntan had shipped to Kinet that allows freight cost extra 40us saved $$$$. if you are a few hours away who cares. you pay 13% at the border sales tax. Some credits are if it is professionally installed only. so kiss your savings on that.
panels I found was the least of my worries, controllers, inverters, grid or off-grid, batteries are the most expensive.
going off-grid, means cutting off hydro. if you decide to go back on Hydro you whole house wiring has to be inspected for certification, an Insurance company will only accept certified solar installation CSA, UL ETL also.

 

[Supervstech]

How is the air seal, and insulation in the home?

heating and cooling are usually the biggest consumers of power... and sealing and controlling the air intake and exhaust in the home make a large difference.

large homes, even MINISCULE air gaps add up to huge energy losses.
Think about the bath vents, the kitchen exhaust, fireplaces, etc... those should all be routed through an hrv energy recapturing appliance... the home wall, and windows need air seals, all piping, and electrical wall and floor penetrations need foam or fire caulk sealing... everything adds up.

 

[Supervstech]

Water heating can be more efficient if tankless is used, tanks can be more efficient if high temps are used, with heavy insulation, and a water mixing valve is installed at the tank. Prevent tank temp drops from excessive cold water mixing in the tank...

 

[maxx123]

Water heating can be more efficient if tankless is used, tanks can be more efficient if high temps are used, with heavy insulation, and a water mixing valve is installed at the tank. Prevent tank temp drops from excessive cold water mixing in the tank...

Question, those electric furnaces can the coils run on DC?

 

[justwork]

how far are you from the border, I purchased used from Suntan had shipped to Kinet that allows freight cost extra 40us saved $$$$. if you are a few hours away who cares. you pay 13% at the border sales tax. Some credits are if it is professionally installed only. so kiss your savings on that.
panels I found was the least of my worries, controllers, inverters, grid or off-grid, batteries are the most expensive.
going off-grid, means cutting off hydro. if you decide to go back on Hydro you whole house wiring has to be inspected for certification, an Insurance company will only accept certified solar installation CSA, UL ETL also.

Question, those electric furnaces can the coils run on DC?

I live about 2 hours from the border, thought about buying south but figured at $0.71CAD a watt for the panels I would rather support local. I'm not sure if the furnace coils can run on DC but I suspect not as they're labeled 15,000W and I believe 240VAC. I'm away from home now for work and don't have access at the moment to double check.

How is the air seal, and insulation in the home?

heating and cooling are usually the biggest consumers of power... and sealing and controlling the air intake and exhaust in the home make a large difference.

large homes, even MINISCULE air gaps add up to huge energy losses.
Think about the bath vents, the kitchen exhaust, fireplaces, etc... those should all be routed through an hrv energy recapturing appliance... the home wall, and windows need air seals, all piping, and electrical wall and floor penetrations need foam or fire caulk sealing... everything adds up.

The air seal and insulation is good, I would say great actually. Our home has a home energy guide rating of 86. The home inspector that checked it out before the purchase said he had never seen anything higher then 83. To be honest I have no idea what the score means. What I can tell you is that we have very high quality double pane energy star windows. We had another inspector come from the province do do a energy evaluation on the house, he did a positive pressure test for any leaks around windows and doors. Our back door, where the kids come in and out all winter, had a worn door seal from ice build up, we had that replaced. All other windows and doors were sealed.

The house is obviously 2X6 construction on the exterior walls. All exterior walls have spray foam insulation. On the exterior of the house we have 1.5" of rigid insulation then the siding. The attic has R20 pink insulation with about 3 feet of cellulose insulation on top. I would imagine a lot of areas have settled over the last 10 years and some of it could stand to be refreshed.

The basement is unfinished, and I'm aware that even a well finished basement can be a heat sink in the winter. The original owner of the house was aware of this too. We have 3" of rigid insulation under the basement slab. The exterior basement walls are stick framed with 2X6 and filled again with spray foam insulation. We have dry wall on the exterior walls as well. I've removed a couple sheets of dry wall to assess the insulation as I am aware that poor quality spray foam insulation can shrink excessively. Ours is all sealed tight still with no cracks or signs of shrinking, I assume the exterior walls on the main floor are in the same condition as this was all done when the house was being built. On the exterior of the basement wall we have the waterproofing membrane down to the weeping tile and on the outside of the membrane we again have rigid insulation which helps provide a break from the frozen ground in winter.

The heat pumps we have are the original heat pumps, which would be 11 years old now. I can't remember exactly how old the house is but between 10-12 years. I'm aware that newer heat pumps are likely more efficient, but they're pricey and ours were at the time top of the line. It would be difficult for me to justify spending the money on replacing them when they work perfectly as is.

I've looked at a couple hot water heating options, solar being one and on demand being the other. From what I've read on demand will offer no savings if it's electric. We would likely need a 27kw on demand heater for our house. Our current electric water heater is 4000w 60 gallon tank. We spend most of the summer at our cottage and the water heater is off during that time. My wife stays home full time with the kids and on demand would likely work out to being less efficient then tank. I've looked at going ng for the water tank but our house was designed for electric utilities, lots of windows, which means almost no place to vent it and be up to code. Same as the furnaces. The solar hot water heaters intrigue me and will likely be something I do down the road. I've also looked at hot water recovery units, where you replace a section of the main stack with essentially a radiator that recovers heat from waste water before putting the fresh water into the tank. From what I've read this preheats the water from about 5C to 20C at the tank, getting 15C for free. However, our kids are young and don't shower they take baths, so you recover nothing from the bath.

Solar water heat is definitely something I want to look at for two reasons. 1 to heat water but 2 I've been toying with the idea of heating my drive way when it needs to be replaced. I've been spit balling an idea of essentially running a grid of pex plumbing under the asphalt. Having a reservoir of glycol in the basement that is heated by solar, when it snows turn on a pump that circulates the heated glycol through the driveway, I would need a large reservoir of solar heated glycol for this to work and likely a tank heater to supplement the heat in the reservoir occasionally. This is just an idea I've had floating around in my brain.

We have a HRV unit in the basement that all the bathroom vents are routed through. It also recirculates the air in the home and replaces a portion of stale air with fresh air from outside. It functions normally and I clean all the filters, intake and exhaust each spring and fall. I also change the furnace filters every 90 days religiously.

 

[Supervstech]

I live about 2 hours from the border, thought about buying south but figured at $0.71CAD a watt for the panels I would rather support local. I'm not sure if the furnace coils can run on DC but I suspect not as they're labeled 15,000W and I believe 240VAC. I'm away from home now for work and don't have access at the moment to double check.



The air seal and insulation is good, I would say great actually. Our home has a home energy guide rating of 86. The home inspector that checked it out before the purchase said he had never seen anything higher then 83. To be honest I have no idea what the score means. What I can tell you is that we have very high quality double pane energy star windows. We had another inspector come from the province do do a energy evaluation on the house, he did a positive pressure test for any leaks around windows and doors. Our back door, where the kids come in and out all winter, had a worn door seal from ice build up, we had that replaced. All other windows and doors were sealed.

The house is obviously 2X6 construction on the exterior walls. All exterior walls have spray foam insulation. On the exterior of the house we have 1.5" of rigid insulation then the siding. The attic has R20 pink insulation with about 3 feet of cellulose insulation on top. I would imagine a lot of areas have settled over the last 10 years and some of it could stand to be refreshed.

The basement is unfinished, and I'm aware that even a well finished basement can be a heat sink in the winter. The original owner of the house was aware of this too. We have 3" of rigid insulation under the basement slab. The exterior basement walls are stick framed with 2X6 and filled again with spray foam insulation. We have dry wall on the exterior walls as well. I've removed a couple sheets of dry wall to assess the insulation as I am aware that poor quality spray foam insulation can shrink excessively. Ours is all sealed tight still with no cracks or signs of shrinking, I assume the exterior walls on the main floor are in the same condition as this was all done when the house was being built. On the exterior of the basement wall we have the waterproofing membrane down to the weeping tile and on the outside of the membrane we again have rigid insulation which helps provide a break from the frozen ground in winter.

The heat pumps we have are the original heat pumps, which would be 11 years old now. I can't remember exactly how old the house is but between 10-12 years. I'm aware that newer heat pumps are likely more efficient, but they're pricey and ours were at the time top of the line. It would be difficult for me to justify spending the money on replacing them when they work perfectly as is.

I've looked at a couple hot water heating options, solar being one and on demand being the other. From what I've read on demand will offer no savings if it's electric. We would likely need a 27kw on demand heater for our house. Our current electric water heater is 4000w 60 gallon tank. We spend most of the summer at our cottage and the water heater is off during that time. My wife stays home full time with the kids and on demand would likely work out to being less efficient then tank. I've looked at going ng for the water tank but our house was designed for electric utilities, lots of windows, which means almost no place to vent it and be up to code. Same as the furnaces. The solar hot water heaters intrigue me and will likely be something I do down the road. I've also looked at hot water recovery units, where you replace a section of the main stack with essentially a radiator that recovers heat from waste water before putting the fresh water into the tank. From what I've read this preheats the water from about 5C to 20C at the tank, getting 15C for free. However, our kids are young and don't shower they take baths, so you recover nothing from the bath.

Solar water heat is definitely something I want to look at for two reasons. 1 to heat water but 2 I've been toying with the idea of heating my drive way when it needs to be replaced. I've been spit balling an idea of essentially running a grid of pex plumbing under the asphalt. Having a reservoir of glycol in the basement that is heated by solar, when it snows turn on a pump that circulates the heated glycol through the driveway, I would need a large reservoir of solar heated glycol for this to work and likely a tank heater to supplement the heat in the reservoir occasionally. This is just an idea I've had floating around in my brain.

We have a HRV unit in the basement that all the bathroom vents are routed through. It also recirculates the air in the home and replaces a portion of stale air with fresh air from outside. It functions normally and I clean all the filters, intake and exhaust each spring and fall. I also change the furnace filters every 90 days religiously.

This sounds great, very little to improve.
Solar water heating, and attic insulation.
Why are your filters changed at 90 days, and not 30?

 

[justwork]

Why are your filters changed at 90 days, and not 30?

Because I always thought the proper interval was 90 days... 30, for real? Hmm, worth a try. My wife is meticulous and the house is vacuumed daily. We also have an ultraviolet light air cleaner within the furnace that automatically comes on when it's running. I've never noticed the filters being overly dirty at 90 but they're inexpensive and if it helps it might be worth it.

 

[BiduleOhm]

You do know a used filter filters smaller particles than a new filter, right? (but has more restriction as a counterpart)

 

[Supervstech]

Because I always thought the proper interval was 90 days... 30, for real? Hmm, worth a try. My wife is meticulous and the house is vacuumed daily. We also have an ultraviolet light air cleaner within the furnace that automatically comes on when it's running. I've never noticed the filters being overly dirty at 90 but they're inexpensive and if it helps it might be worth it.

It all depends on the filter construction, and air volume through the media.
1" filters generally run about 30 days, 2" go 90 days, and 4" go 6 months...
Is surface area is large enough, and air volume is low enough, a 1" filter CAN go 90 days, but it would need to be HUGE

 

[justwork]

It all depends on the filter construction, and air volume through the media.
1" filters generally run about 30 days, 2" go 90 days, and 4" go 6 months...
Is surface area is large enough, and air volume is low enough, a 1" filter CAN go 90 days, but it would need to be HUGE

Good to know. Thanks. My old house had a ng furnace with a 4” filter and I did change that every 6 months because the filter was about $30 and had to be ordered online as no shops stocked it.
My current filters are 1” and normal sized something like 18X20 in each furnace (two furnaces, one for each floor).

 

[Danny]

Do enphase iq7a maybe not the old enphase. Here is the play list of all the things I did on my project and considerations in the US but much will be the same in Canada. Good luck. https://www.youtube.com/playlist?list=PLCal7Co3mAHSR5tg48M8NGKBcjBso8Wle

 

[justwork]

Do enphase iq7a maybe not the old enphase. Here is the play list of all the things I did on my project and considerations in the US but much will be the same in Canada. Good luck. https://www.youtube.com/playlist?list=PLCal7Co3mAHSR5tg48M8NGKBcjBso8Wle

Thanks, I actually checked out most of your videos already - great job