A new construction home in Ada County now carries a median price of $629,000. An existing home carries $579,900. New construction is running $49,100 more expensive, and that gap opened almost entirely in one month.

This report covers August 2026, the most recent month Boise Regional REALTORS® has published in full. Their stat sheets run roughly six weeks behind the close of a month, so the newest complete picture is always a month back. Figures are Intermountain MLS data as of September 8, 2026.

Year over year the split is just as sharp. New construction prices rose 13.8% while resale rose 3.6%. Those two numbers describe the same county in the same month.

The builder discount everybody spent this year hunting for is no longer where it was.

Look at either half on its own

The countywide average hides the most useful thing happening in Ada County. Switch between the segments and watch what changes.

Why the gap opened

Before anyone concludes that new homes appreciated 13.8% in a year, it is worth saying plainly what a median is. It is the middle sale, not the average gain. If builders closed a larger share of expensive homes in August, the median rises even if no single house gained a dollar.

That is almost certainly part of what happened here. Builders control which homes they finish and close, and their month-to-month mix swings far more than the resale market’s does. The year-to-date numbers make the point: new construction is up 0.2% for the year at $575,990, against 13.8% for the single month of August. One of those figures describes a trend. The other describes August.

The resale side tells a steadier story. Resale is up 2.7% year to date at $564,900, and up 3.6% year over year in August. Less drama, more signal.

The number that actually matters

Underneath the price noise, one figure moved in a way that affects every buyer in this county. Ada County resale supply fell to 1.9 months, down from 2.5 a year ago, a drop of 25.5%. Resale inventory is down 17.3%.

Anything under four months is generally considered a seller’s market. Under two months is scarcity.

Here is the part worth sitting with. Resale and new construction are carrying almost identical numbers of homes, 991 against 988. But resale sold 658 of them in August and new construction sold 297. Same shelf, very different turnover. That is the whole reason one side shows 1.9 months of supply and the other shows 3.4.

So the leverage did not disappear. It moved. Builders still hold more standing inventory relative to how fast they sell it, which is where negotiating room lives. What changed is that the sticker price is no longer the place you find it.

Run your own numbers

A median is a starting point, not a payment. Move the sliders to see roughly what a given price costs each month.

Where you stand right now

The Micron factor

Any honest read of this market has to account for what is being built in southeast Boise. Micron is investing roughly $50 billion in two semiconductor fabrication plants, with the first expected to begin production in 2027 and the second in 2028.

The job figure gets repeated carelessly, so here is the careful version. Micron employs about 7,000 people in the Boise area today and expects to add roughly 3,500 direct positions at the new sites. The widely quoted 17,000 figure includes indirect and construction jobs across suppliers, builders, and related firms, and some of those will land outside Boise.

Even stated conservatively, that is a large amount of new housing demand arriving into a county already carrying 1.9 months of resale supply. It is a meaningful part of why inventory keeps tightening while sales volume climbs.

What to watch

Rates are the live risk heading into winter. Federal Reserve Chairman Kevin Warsh signaled in late August that a rate increase was possible this fall if inflation did not come down, noting that July PCE inflation ran at 3.7% against the Fed’s 2% target. Markets repriced sharply after those remarks. Worth keeping in mind that the Fed controls short-term rates rather than mortgage rates directly, so the two do not move in lockstep, but the direction of travel still shapes what buyers can afford.

Locally, two infrastructure projects matter if you are watching the western valley. Middleton broke ground on a $68 million wastewater treatment plant expansion, and Nampa received a $23 million federal BUILD grant for bridge widening, resurfacing, sidewalks, and signals. Both expand the capacity those cities need to keep absorbing growth.

Seasonally, the market cools from here. The question for the next few reports is whether resale supply stays under two months through the winter, because that more than any price headline will decide what spring looks like.

Questions people are asking

What is the median home price in Boise and Ada County right now?

The Ada County median sale price for single-family homes was $595,000 in August 2026, the most recent month reported in full, up 6.9% year over year. Existing homes came in at $579,900 and new construction at $629,000, according to Boise Regional REALTORS.

Is new construction more expensive than resale in Boise now?

Yes, and by a wide margin. In August 2026 the Ada County new construction median was $629,000 against $579,900 for existing homes, a difference of $49,100. A month earlier the gap was only $9,900. New construction prices rose 13.8% year over year while resale rose 3.6%.

Did new construction really appreciate 13.8% in a year?

Not in the way that number suggests. A median reflects which homes sold, not appreciation on any individual property, and builders control their closing mix far more than the resale market does. New construction is up just 0.2% year to date at $575,990, which is the better measure of the trend.

Is the Boise housing market a buyer’s or seller’s market?

A seller’s market, and tightening. Ada County held 2.4 months of supply overall in August 2026, and the resale segment fell to 1.9 months, down 25.5% from a year earlier. Anything under four months is generally considered a seller’s market.

How long do homes take to sell in Ada County?

The countywide average was 37 days in August 2026, down from 41 a year earlier. Existing homes averaged 30 days while new construction averaged 54.

Can I still negotiate with a builder in the Treasure Valley?

Yes, though not usually on price. New construction carried 3.4 months of supply in August 2026 against 1.9 for resale, and averaged 54 days on market, so standing inventory still offers room. Builders protect list price to defend their community comps, which means concessions come through rate buydowns, closing cost credits, design allowances, and lot premiums instead.

How is the Micron expansion affecting Boise housing?

Micron is investing roughly $50 billion in two Boise fabrication plants, with the first expected to begin production in 2027. The company employs about 7,000 people locally and expects to add roughly 3,500 direct positions, with a wider figure of about 17,000 jobs that includes indirect and construction roles. That demand is arriving in a county already holding under two months of resale supply.