A sunroom or porch with a western exposure may become extremely hot during the summer, although as you point out you can mitigate that somewhatby opening windows, fans and of course, the old fashioned favorite of slatted blinds (though covering the windows with slatted blinds all day somewhat defeats the light-trapping effect of a sun room). On the plus side it will protect the main house from excess heat during the hottest months when the sun is high in the northwest late in the afternoon. You may be surprised how extremely hot a west/northwest-facing sunroom can get on a long, clear day in July - in can be brutal! The downside of a northwestern orientation for a sun room is that in the winter it will get only reflected light, no direct solar gain, which may make it a chilly space. You didn't mention whether you plan to have the space separated from the main house by walls and doorways. That would be best, because otherwise the sun-room temps, good or bad, will be a challenge to the indoor climate and the heating and cooling devices you are using. If you can close off the space when needed you can take advantage of any favorable temperature exchange, while limiting the unfavorable conditions, especially at night in the winter, or late afternoon in the summer. In response to the suggestion that is a good thing to locate a sunporch on southern expoasure in the north: Acually having a sunporch on the southern exposure is the worst in a cold, northern climate. Not because the space doesn't get warmed directly by the sun during the day, of course it does. The problem comes when the sunporch changes the way light penetrates into the main house, creating a cave effect in the interior making it feel cold and dark in the winter. The net effect of this is to degrade the existing space in favor of the more marginal, and harder to heat, sun trap space. People often get confused by this idea, since we all know that designing a house with good passive solar orientation is great thing. It's good for energy savings, and it makes rooms very attractive and livable. But it falls down when the sun trap space projects beyond the main vertical elevation of the largest massing of the structure. This then creates the depressing, energy wasting space in the (now) deeper interior. You have to evaluate the siting on a case by case basis, as a rule, the more directly southern the exposure, the worse it is. In general, I think an eastern facing sun room is probably best in the south, and a western one (as long as it can be isolated by doors and walls) is the best choice in the north. As far as the OP's thoughts about heating: most add-ons like this will present very complicated problems for a wood stove chimney which must be tall enough to rise above nearby taller parts of the house. From the OP's descrition of the dimensions it sounds hard to find a suitable place for such a chimney. It's always possible there's an existing location that could be used, but generally wood stove chimneys don't draft well (with all the attendant safety and air quality issues of poor draft) unless they are up in the clear. You might however consider either a propane/gas or pellet burning stove, both of which can usually be directly vented through the walls with a minimum of fuss. Electrtic heat is probably the simplest and cheapest to install, but not usually the cheapest to run. But if you are not sure how much you will use the space, then it might be a good initial choice as a trial, as the DV stoves can usually be easily added later. I'd still recommend you create a scale model of the space and the main house (easy to do with cardboard from boxes and tape) and do a mock up. Make it big enough (at least a couple of feet) so you can look in and through it and experience the change of light you are proposing. If you like it, then you will be happy with the results, at no cost other than an afternoon spent making the model. Just make sure when you are standing outside looking through the model that it is oriented exactly the same as your house. L

Teak oil, perhaps? https://www.dalyswoodfinishes.com/store/index.php?main_page=product_info&cPath=4&products_id=16

A lot depends on the look you want. We're also doing a screen porch and will use a composite (not sure which yet) but the type that is interlocking and looks like T&G after install. You can't stain a PT deck immediately so it will have to weather as is for a while - how long I believe depends on how much weather/sun exposure it will get but I believe a year is recommended. Will you be screening underneath the PT flooring to keep bugs out? How will it be fastened? Will they do a blind system so you don't have to see nails in the boards?

I don't like light colored flooring for a porch. My sunroom porch floor is a light color tile and it looks like an indoor product, not a porch floor to me. My house is a vintage house with dark wood trim, inside and outside, so a slate look is my likely choice. If you have a light colored exterior with a beachy style, a light floor might work but I wouldn't use it for a traditional style house