Passive solar- more appropriate windows is better?

We're designing a house for an acreage and are in a very rough stage of the build. Basically, we are thinking that, if passive solar works by hitting a material that absorbs sunlight through a window, you want to maximize the percentage of the floor space (and wall space) that is hit by the sun in order to create the most heat gain. As such, our design is a long, very thin house, 18x40ft (no kids, and the house could have rooms added if needed, there is an external door planned specifically for this). The south-facing side, one of the long sides, will be covered entirely by giant windows, floor to ceiling, one immediately after another, shining onto the tile below. We figure this would get the most heat. However, this makes us wonder about the consequences on the insulation. As windows are not as insulated as a wall, is there a point of diminishing returns, or is every window that covers enough floor space still a good addition? Is the giant window not going to fly, and we need smaller ones for more insulation? Thank you for your help!

Edit: It's worth noting this is in Canada. Winters can get as cold as -20. There is a wood furnace in the design, and there will also be a heat recovery ventilation system, as well as electric heated floors that will kick on in the result of the temperature getting too low.

-20C = -4F which gives a USDA zone 6. Which to me is pretty avg.

Floor Space= 40ft*18ft = 720sqft
Window Space = 40ft*8ft = 320sqft
Percentage = 320/720 = 44%
Your percentage and your latitude are both around 44 so, you should be fine. Do use triple or double pane windows. And use an outside curtain/sunshade for the summer months.

How thick is your thermal mass on the floor (5inches+)?

S Bengi wrote:-20C = -4F which gives a USDA zone 6. Which to me is pretty avg.

Floor Space= 40ft*18ft = 720sqft
Window Space = 40ft*8ft = 320sqft
Percentage = 320/720 = 44%
Your percentage and your latitude are both around 44 so, you should be fine. Do use triple or double pane windows. And use an outside curtain/sunshade for the summer months.

How thick is your thermal mass on the floor (5inches+)?

The worst of the days (maybe 5-10% of winter days?) can reach -30, and I have seen -35 and once in my life -40, but hey, those days are what we have the wood stove for!
How do the percentage and latitude calculations like that work? Any sources I could learn more about that!
Yeah, definitely will be using something like that for the summer month, no need to bake ourselves lol. Thank you!
Edit: We will make it as thick as it needs to be- we are planning now.
Edit 2: A source here indicates it may be considerably too much, but I assume this is america. What do you mean with latitude? I'm a tad confused about how this all works out. Source: https://www.greenbuildingadvisor.com/article/cost-effective-passive-solar-design

With PEX piping you would have been able to more easily distribute the heat around the house, after absorbing it from the areas right under the window.

What is the R value of your roof, walls and floor?

S Bengi wrote:With PEX piping you would have been able to more easily distribute the heat around the house, after absorbing it from the areas right under the window.

What is the R value of your roof, walls and floor?

The R values of the envelope are not yet determined, but we will likely do them as high as they need to be to absolutely minimize the heating bill without cooking ourselves in the summer. I do not know what PEX piping is. We are quite new to this, and willing to learn! I will google that, but do you have any information for me? The planning has just begun, and we actually wanted to start with this window and passive solar, other than the size and shape of the house. This is a new build! We are planning it from scratch.

Double or triple glazing would be best.
Thermal mass in walls will help a lot.
Pergola or shade cloth or system will be needed in summer.
You can design eaves to exclude summer sun.
For winter nights consider heavy drapes with pelmets to hold heat in.

PEX is a type of plastic pipe that you can put into the floor before you pour the slab, so it's inside the slab. You run slowly pumped water through it and it takes the heat from the solar heated areas of the slab and spreads it to the cooler areas.
Look up the words "hydronic heating" or "solar hydronic heating"  to learn more than you probably need to about it, that will give you the idea how it is done, so you can look at how to use it on your build. You will mostly see how to hook it to a boiler of some sort, but it will give you the basic idea. Looking it up, try also "radiant heat floors"

I can expand on this, but looking up that term will give you a lot more info faster than I can type it :)

With the pex piping you can also You are not limited to distributing heat just from solar heated area. You can also attach a electric instant hot water heater, a heat pump, domestic hot water heater, or from a pellet wood stove hot water heater, or a solar water heater.