AOS vs PNR: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of October 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

Reading it: PNR is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. AOS and PNR share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined AOS and PNR exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

A. O. Smith is a Milwaukee-based manufacturer of water heating and water treatment products. Its core business is residential and commercial water heaters and boilers, where it is one of the top players in North America alongside Rheem and Bradford White, plus a faster-growing line of water treatment and filtration products. The North America segment drives roughly 78 percent of sales, and the Rest of World segment (around 22 percent, a majority in China, with a rising India contribution via the Pureit brand) is the international lever. Much of North American demand is non-discretionary replacement of failed units, which gives the revenue base a defensive, recurring quality.

Full AOS guide

Pentair plc is a roughly $4 billion revenue water treatment and flow company that most consumers know through its Pool segment, which makes pumps, filters, heaters, automation, and sanitization gear for residential and commercial swimming pools. Beyond pools, the Water Solutions segment sells residential and commercial water treatment (softeners, filtration, and quality systems) plus, after a January 2026 reorganization, the residential and irrigation flow business, while the Flow segment covers industrial, agricultural, and municipal pumps and fluid-handling equipment. As of October 16, 2026 Pentair carries a market capitalization near $8.6 billion and trades around $53, less than half its 52-week high near $112. On October 1, 2026 it completed the roughly $1.4 billion acquisition of Taco Group, financed partly with term loans, adding hydronic and flow products to the portfolio.

Full PNR guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• AOS drivers: North American replacement demand; Water treatment and India (Pureit).
• PNR drivers: Pool as the profit and growth engine; Transformation and margin expansion.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: China remains the biggest swing risk, with Rest of World sales pressured by a double-digit China decline that can mask North American strength. For PNR, pool and water-treatment demand is cyclical and sensitive to housing activity, discretionary spending, and interest rates, and 2026 showed how fast that can bite: Pool sales fell 42% in Q2 on dealer destocking, and some analysts have raised the possibility of dealer share loss rather than a pure inventory reset.

Pick AOS if you believe its drivers more; PNR if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the AOS and PNR guides.

AOS. At about $59, AOS trades near 16.6x trailing and 14.7x forward earnings, toward the lower end of its quality-industrial range after a 13% decline this year. The first quarter missed (EPS $0.85 against $0.94 expected) and the second beat ($1.03 against $0.92), leaving full-year earnings expected slightly below 2025. The October 29 report carries consensus of about $0.90 of EPS on $963 million of revenue.

PNR. Pentair trades around $53 in mid-October 2026, roughly half its 52-week high near $112, at about 13.7x trailing and 10x forward earnings with a dividend yield near 2 percent, the cheapest it has looked in years on those measures. The discount reflects a falling top line (Q2 sales down 17%) and cut guidance rather than a margin story still working. Consensus for Q3, reported October 27, is about $1.07 of EPS on ~$964 million of revenue, both below last year.

Headline figures (approximate, October 2026): AOS shows revenue (ttm) ~$3.8B (Q2 2026 ~-1% YoY), net income (ttm) ~$500M (profit margin ~13%), q2 2026 eps $1.03 vs $0.92 expected, p/e (trailing / forward) ~16.6x / ~14.7x; PNR shows revenue (ttm) ~$4.0B, q2 2026 sales ~$933M (down ~17%; Pool down ~42%), margins (ttm) Gross ~41%, operating ~23%, net ~16%, net income / eps (ttm) ~$636M; GAAP EPS ~$3.88.

AOS and PNR are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined AOS and PNR exposure against your real portfolio. It is not an investment adviser.