Single-story vs two-story custom home: which is better in Arizona?

For most Arizona custom homes a single-story layout is the default choice, with two-story winning on cost per square foot and on tight lots. A two-story home stacks living space, so it needs less foundation and less roof per square foot, which lowers cost per foot and fits a smaller parcel. A single-story spreads everything on one level, which costs more per foot but is easier to cool evenly, simpler to age in, and lighter on the structure. Your lot size, your budget, the desert heat, and how long you plan to stay all push the decision. There is no answer that fits every owner, but there is a clear answer for your lot and your plans. Below is the real trade-off on each one.

Cost per square foot: two-story usually wins

A two-story home almost always costs less per square foot than a single-story home of the same total size. The reason is geometry. A single-story home puts the entire floor area on one slab and under one roof, so it carries the most foundation and roof per square foot of living space. A two-story home stacks the second floor on top of the first, cutting the foundation footprint and the roof area roughly in half for the same square footage.

Foundation and roof are big line items. In the NAHB 2024 construction survey, framing (which includes the roof structure) and the foundation are among the largest construction stages. Spreading a home across one level multiplies both, which is why a sprawling single-story custom home costs more per foot to build than a compact two-story with the same square footage.

Two-story homes save in two more places. Plumbing runs shorter when you stack bathrooms above each other, and the mechanical and roof systems cover less ground. The savings are real but modest, usually a single-digit percentage per square foot, not a transformation of the budget. Finishes, lot work, and your selections still drive most of the cost. For the full list of cost drivers, see /faq/what-drives-the-cost-of-building-a-custom-home-in-arizona.

Cooling load and the Arizona heat

The desert heat is where single-story and two-story homes behave differently, and it cuts both ways. A two-story home has less roof exposed to the sun per square foot, and the roof is the surface that takes the worst of Arizona's solar load. That can lower the cooling demand on the upper part of the house. But hot air rises, so a two-story home tends to run warm upstairs and cool downstairs, which means the upstairs air conditioning works harder and rooms can feel uneven.

A single-story home is easier to cool evenly because there is no stacking of heat. One well-designed zone, or a couple of zones, can hold a consistent temperature across the house. The trade-off is more roof soaking up sun, so the cooling system has more roof-driven heat gain to fight. Good insulation, radiant barriers, and a cool or light-colored roof matter on a single-story home for exactly this reason.

Neither layout is automatically cheaper to cool. What matters more is the building envelope: insulation, window specs, shading, and a right-sized HVAC system designed for 110-degree summers. A two-story home usually wants zoned cooling, with separate control for up and down, to fix the uneven-temperature problem. Budget for that zoning when you price a two-story build. Either way, 96 percent of new homes have air conditioning, per the Census Bureau, and in Arizona it is the system you design around first.

Lot size, setbacks, and the view

Your lot often decides the question before cost or comfort do. A two-story home fits a smaller lot because it stacks the same living space on half the footprint, leaving more yard, driveway, and setback room on a tight parcel. On a standard subdivision lot in Phoenix, Gilbert, or Casa Grande, going up can be the only way to get the square footage you want while still meeting the setbacks and lot-coverage limits your zoning allows.

A single-story home needs more land, because the whole house sits on one level. On a generous lot in Rio Verde Foothills, Cave Creek, or north Scottsdale, that is no problem, and the sprawling single-story ranch is the signature desert custom home for a reason. On a small lot, a single-story large home may simply not fit within the buildable area.

The view changes the math too. On a view lot, a two-story home lifts the primary suite or a great room up to capture mountain or city views that a single-story would miss behind walls and neighbors. That is a common reason owners on Scottsdale and Fountain Hills hillside lots choose to build up. Check your lot's zoning for height limits and lot coverage before you commit, since some hillside and dark-sky areas in Maricopa County cap building height.

Soils, structure, and aging in place

Two factors that get overlooked are how the home loads the soil and how it works as you age. Arizona's expansive and collapsing soils make foundation design a real concern, and a two-story home puts more weight on the same footprint. The Arizona Geological Survey warns that collapsing soils "shrink when wetted, and/or when loaded with a great weight, such as a building or pavement," and that expansive soils cause "foundation cracks" and "heaving and cracking of floor slabs and walls." A geotechnical soils report drives the foundation design for either layout, but the heavier point loads of a two-story home can call for a more engineered foundation on poor soil. This is one reason a soils report is not optional here.

A two-story home also brings stairs, which carry their own code and life-stage trade-offs. Under 2018 IRC R311.7.5, residential stair treads must be "not less than 10 inches" deep, and a handrail is required on any flight with four or more risers. Stairs are fine for most buyers, but they matter if you plan to age in place. A single-story home has no stairs to navigate later, which is why many owners building a forever home in Arizona choose single-story, or at least put the primary suite and laundry on the ground floor of a two-story.

Here is the short way to decide. Pick a two-story home if your lot is small, your budget is tight per square foot, or you want to lift living space to a view. Pick a single-story home if you have the land, you want even cooling and no stairs, and you plan to stay for the long haul. Many Arizona owners split the difference with a single-story main home plus a casita, or a two-story with everything you need on the ground floor. Whatever you choose, design the envelope and the cooling for the desert first, and get a soils report before the foundation. These cost differences shift with material and labor prices, so confirm current per-square-foot pricing with your builder on your actual plan and lot.

The Jematell Homes approach

Setbacks, overlays, and ADU rules shape our design work from day one. Every project is different, so we will confirm the specifics for your parcel and budget with you directly.

Sources

• Arizona Geological Survey: Problem Soils (expansive and collapsing soils)
• U.S. Census Bureau: Highlights of 2024 Characteristics of New Housing
• NAHB: Cost to Construct a Home Rose Significantly Over Last Two Years (2024 survey)
• 2018 IRC R311.7.5 (Stair treads and risers)