Depends on site but if you have walkout topography, I vote basement. The walkout rooms can be just as inviting and light filled as the upper levels if done right. Basements almost always have slabs so no conflict there.

The main problem with attic living is that most designs and typical construction details result in an inferior building envelope in terms of airsealing and insulation (comfort, energy use, moisture resistance). If you choose a designer and builder team familiar with passive house details then it should be less of a problem. We typically use SIPs for enclosing attic living spaces.

I'm always amazed at how blasé country posters are about their acreage.

For this city dweller, given three wooded acres, no question but a second floor (attic) would be my first choice!

Still, you can plan for finished basement space as well, providing at the least for an egress window.

If you are required to go deep to get under the frost line be for your foundation, then you’re already going to have a basement. If you’re in 12”D footing with slab on grade, then your water heater and hvac will already be located in your attic—to its detriment.

Location and local build norms come in to which approach will be more economically done.

"I'll use an architect when I'm ready"

You are ready.

Do you plan to hang on to the house for an extended time period? Is resale important to you?

Building a 1400-1600 one bedroom house seems like an investment which may not resale to very many people. Have you considered adding a second or third bedroom and another bath and a half?

First, yes, your geography makes a great deal of difference. If you're in the north and will already be forced to "dig down" for your foundation, a basement is the obvious choice, whereas we Southerners just don't do basements.

Second, the house you show is clearly a beach house. Suitable for a narrow lot, lots of bedroom space, tiny closets in the master ... does this fit with your plans?

Do I understand correctly that you're choosing between future bedrooms upstairs /future bedrooms in a basement? One important question is, if you go with the basement, will your slight slope allow for egress windows? Also, I understand bathrooms in basements aren't the easiest things to build; you have to "pump up" the water /waste to ground level.

Finally, are you able to do this as a cash build? I ask that because no bank is going to loan for a one-bedroom house.

Thanks for all of the comments. I am building in the northeast. The passive house style slabs are relatively shallow even in my climate due to foam below and around the perimeter of the slab. The main thing drawing me to a basement is that basements are typical where I live, but I prefer the idea of having the higher up views from the attic, as Worthy pointed out. I've also thought about building a house with second floor living space and four car garage below, that could be become a couple of bedrooms in the future.

The reason I don't want to build all the bedrooms now is because I don't really want a big house to take care of. It doesn't fit my life. But I also don't want a too-small house that is limited in livability for others. I think I will mainly finance the project myself so I am not worried about banks, but I do want to plan for the reality of the market.

And Sophie, thanks for pointing out the water heater/HVAC issue. That is something I wasn't thinking of.

We built a small, 1400 sq ft one level, one bedroom home on a full, walk-out basement. Since it's open, and there's only one BR on the main level, it doesn't feel small at all. We considered going up as well, as I like the looks of a 1-1/2 or two story house. We went basement instead, for the following reasons:

Our sloping ground was ideal for a walk-out basement.

We built with ICF, so the basement was already well insulated.

After living in FL for 30 years, we wanted a place of safety in bad weather.

After living on a slab for 30 years, I prefer the slight give of a suspended floor.

I can easily reach and service wiring, plumbing, and HVAC refrigeration lines from the basement.

I was one old man, working alone, so the thought of climbing up on a two story roof gave me the willies.

Due to careful work and multiple systems, our basement is snug and dry. With the ICF construction, our basement never falls below 60 F., or goes above 75 F. with no HVAC at all. I recently framed and drywalled interior walls to create a bedroom, bathroom, and large storage closet in the basement. I have room for another BR, and now wonder why I didn't rough it in at the same time.

The only issue we've had with a one BR house is that there's no 'away' space except to go outdoors (or out to my barn). With the second bedroom in the basement, if I want to retreat to a quiet corner and read, we now have a space for that. Although we're almost always in the same room at the same time, don't underestimate the value of being able to get away, or to house an overnight guest (which we do fairly often).