Images?

Whoops, added.

The long axis of the house needs to run east west.

How much slope is there?

The lot appears to be entirely wooded, you'd have to cut down a lot of trees in order to get full benefits of passive solar design. I don't think this is the lot for you if you want to go that route.

There is about a 15% slope.

We plan on clearing some trees around the property, but I don't know how much we would need to clear to get the benefits. I want to take advantage of the light from the south, but may that is not possible on a wooded lot like this?

Deciduous trees that lose their leaves can filter out harsh summer sun and let in the welcome winter warmth.

Those are 4 foot contour lines? If so, that is quite a slope to have from right to left on a house. Would have to be built on an exposed basement or piers, and so living areas would not have direct access to the ground on the long south side. But you could have a deck in stead of a patio.

Summit, while it is the case that the leaves will not be effecting the winter solar passive properties, the countless Passive Solar construction books and articles that I've read in the past 3 years have strongly recommending having barely any trees on the southern exposure as even the trunks of the trees can play a major role in blocking the sun's rays. I can't imagine how ineffective it'd be with such a dense wood as seen in the picture.

The OP would have to clear out a lot of trees, which seems very counter intuitive to one of the main elements of leaning towards a passive solar house.

@ulisdone, yes 4 ft contour lines. I was thinking that would be a big slope also for a house with the length being right to left. We have basements here, so I am having a hard time picturing that.

I'm surprised you have basements in Missouri.....You are in the S.....

Thinning the trees can get you the winter sun and add privacy and outdoor shade in the summer. A correctly sized overhang will be the primary shade to keep summer sun from coming in the windows you use for winter solar heat. I wouldn't leave trees close enough to the house to be the main shade source. A contemporary design could be angled across the lot with the windows on a N-S axis with return walls on the angle. You'd need some creative design work. I'm not seeing much of a street-side façade.

That is a huge slope. That costs some serious money to build on. Additionally, you will be significantly lower than the street so there will be no visibility or "curb appeal" there. You might not care but in my area, that lowers resale value quite a bit. There is a reason that lot was not the first to develop. Passive solar aside, I don't like the lot for the slope reasons. I am sure it could be made great but it would cost significant amounts.

In my area, poor lots are not discounted enough because buyers don't realize how much money goes into making it work. Builders know - but buyers wanting to do a custom house don't. Non builder buyers are just excited to get such a good price. Just a warning - not saying that is happening in your area.

I personally see no issue clearing tons of trees on the south side for your solar desires. But - know that aggressive passive solar has its downside. Some passive is great, trying to fully eliminate heating needs is foolhardy. In the end, you don't save enough money often to justify the consequences.

This is Missouri - my understanding is that it is both pretty cold and pretty hot. Insulate and air seal. The southern exposure is good too - but mostly for livability.