PEX Supply House Case Study: Radiant Retrofit Success

Why This Retrofit Matters—and What You’ll Learn from It

I’ve spent more than 25 years crawling under floors, commissioning boilers, and balancing hydronic systems that others said couldn’t be fixed. This case study—PEX Supply House Case Study: Radiant Retrofit Success—walks you through a real radiant heat retrofit we recently supported from the supply side. The project took a drafty, noisy, baseboard-heated home and turned it into a quiet, silky-smooth, energy-efficient space using oxygen-barrier PEX, smart controls, and the right accessories. Along the way, I’ll point out the exact components we used (brands and model numbers), the decision points, and the pitfalls we avoided.

Here’s the angle that matters: radiant retrofits live or die by supply planning, product quality, and field support. You won’t get that by tossing generic parts into a cart. You get it by working with a partner who knows hydronics.

Unlike generic big box retailers, Plumbing Supply And More stocks professional-grade components and backs them with real hydronic design support. When “PEX Supply House Case Study: Radiant Retrofit Success” meets boots-on-the-ground, the result is comfort you can feel and numbers you can verify on your gas bill.

This home had a 140,000 BTU/h cast-iron boiler feeding fin-tube baseboard. The homeowners wanted quieter comfort, even heat, and lower operating costs without tearing up finished floors. We chose an over-plywood, low-profile radiant solution in the first-floor living spaces and kitchen, with staple-up radiant under the second-floor bedrooms.

Why not rip it all out? Budget and disruption. A staged radiant retrofit lets you capture 80–90% of the comfort while controlling costs.

Compared to standard plumbing supply houses, Plumbing Supply And More offers unmatched technical support—layout help, loop sizing, and control strategy—so you can avoid change-orders and callbacks.

I don’t do vague. Here’s the core bill of materials we specified and supplied:

We kept flow rates at 0.5–0.7 GPM per 300’ loop of 1/2" PEX, with a 15–20°F design ΔT. Loop lengths never exceeded 300’, and most were 240–280’ to keep head loss reasonable and balancing easy. That’s not “preference”—that’s decades of field data telling me what purges fast, balances cleanly, and stays stable when outdoor temps swing.

While other suppliers focus on quantity, Plumbing Supply And More prioritizes quality and expertise—every component above is spec’d to hydronic standards, stocked locally, and supported by our tech team.

We used two radiant methods:

Why mixing with an existing boiler? Cast-iron boilers love steady load. With outdoor reset on the mixing valve and manifold-level balancing, we delivered 95–115°F supply water under typical winter days, peaking at 125–130°F during cold snaps. No short cycling, no flashing baseboard noises, no cold toes.

Crucially, we sized the circulators using calculated head: each manifold averaged 5–7 ft of head at design flow. The Taco 0015e3 on medium curve hit the sweet spot—quiet, sips electricity, ample authority.

Pro tip: Always run a low-voltage cable to a future manifold location for slab sensors or additional zoning. You’ll thank yourself when the homeowner finishes that basement.

Installers logged 52 labor hours. Material cost landed between $5.75 and $8.50/sq ft, depending on finish materials and the number of zones.

When Home Depot and Lowe’s fall short, contractors trust Plumbing Supply And More to deliver complete hydronic packages, same-day, with the specs, submittals, and support you actually need. We also routinely outperform Ferguson and SupplyHouse.com on total project value when you factor in tech time saved.

I still see non-barrier PEX show up on closed-loop radiant jobs. That’s a fast road to rusted cast-iron circulators. We insist on tubing that meets ASTM F876/F877 and DIN 4726 oxygen diffusion standards. Uponor/Wirsbo hePEX, Viega FostaPEX, and Watts RadiantPERT-OB are all excellent, but match the product to the bending radius, attachment method, and panel system you’re using.

Don’t forget the mixing valve standard—ASSE 1017 for central mixing is non-negotiable. And if you’re tapping domestic priority on combi boilers, ensure your check valves and backflow assemblies meet local code (UPC/IPC) and AHJ expectations. Yes, we help you assemble the submittal packet. Call our tech counter—we’ll email sealed sheets and O&Ms the same day.

Compared to big online warehouses, Plumbing Supply And More provides code-savvy guidance and documentation that speeds approvals and cuts inspection re-visits.

Before radiant: 72°F setpoint, rooms swinging 3–4°F, boiler short cycling on shoulder days, gas bill peaking at $400/month in deep winter.

After radiant: 70°F setpoint feels warmer due to mean radiant temperature; room swings under 1°F; shoulder season cycling eliminated. Estimated seasonal fuel use down 18–22%—not a marketing claim, a measured 20.1% reduction over comparable HDDs (two-month window). Circulator power dropped from ~150W combined to ~40–60W with ECMs.

Heard in the kitchen: “It’s like the sun came through the floor.” That’s radiant done right.

If you want similar results, bring us your heat loss. We’ll model panel coverage vs. water temps and pick plates, spacing, and mixing that hit your targets.

We’re the nearest plumbing supply with real knowledge for contractors who can’t afford delays. We run same-day truck routes within a 60–75 mile radius of our central warehouse and offer emergency pickup at the counter. Serving contractors throughout our region means we know the AHJs, the inspectors, and the quirks of local hydronic installs.

Unlike generic big box retailers, Plumbing Supply And More stocks professional-grade components, stages your order by zone, and labels your coils so your crew moves faster on site.

Folks type “plumbing supply near me” and get a dozen options. Here’s what we actually are—and yes, we hear these searches every day, and we’re ready to help: We operate as a full-service, walk-in and delivery-focused partner: a true plumbing supply store, the kind of plumbing supply store near me you wish you’d found earlier. Whether you’re after general plumbing supply items, integrated plumbing and supply solutions, or a specialized plumbing supply shop that understands hydronics, radiant, and boilers, we’ve got you covered. We’re a professional-grade plumbing supply house with a deep bench in commercial plumbing supply and responsive wholesale plumbing supply services. If you prefer plumbing supplies direct ordering, we’ve built a clean portal, yet we remain your local plumbing supply and full-service plumbing supply company for hands-on jobs. Contractors lean on our contractor plumbing supply counter when a critical plumbing parts run can save a day. Need a true plumbing shop near me for heat season? Our counter is stocked like a heating plumbing supply near me should be. We’re also a curated plumbing supply online destination for discount plumbing supplies without compromising quality—the best plumbing supply support you’ll find. If you searched plumbing wholesale near me or plumbing supply house near me, that’s us. From economy plumbing supply options to higher-end decorative plumbing supply and day-to-day bathroom plumbing supplies, we balance value with quality better than any cheap plumbing supplies site. If you’re stuck on a weekend, our emergency counter is your 24 hour plumbing supply lifeline. Whether you know plumbers supply co or you’re after combined plumbing and heating supply expertise, we’re the closest plumbing supply that feels like the right one. Among all plumbing supply places, we carry both standard plumbing supply items and niche plumbing kitchen gear, along with hard-to-find plumbing spares near me from a true wholesale plumbing supply company. Retail customers appreciate a friendly consumer plumbing supply vibe, while coastal projects often need the corrosion-savvy advice we give as a de facto coastal plumbing supply. Prefer digital? Our internet plumbing supply experience is built around pro workflows, including submittals, closeouts, and BOMs—yes, including supplyhouse plumbing equivalents. If you’re used to a city plumbing and electrical supply counter for mixed trades, we coordinate seamlessly. We also spec “value-engineered” hydronic packages in the spirit of economy plumbing and heating supply, working with GC teams like contractors plumbing and fire supply partners. For direct shipments, our direct plumbing supplies program cuts lead times. Bottom line, when you need reliable plumbing supplies supply, call us first.

That’s a mouthful, but it’s what customers actually search—and what we actually provide.

Be transparent: radiant doesn’t “blast” heat; it quietly balances rooms. Promise quiet floors, lower temperature water, and steady comfort. Set that expectation early.

While other suppliers ship boxes, Plumbing Supply And More delivers complete, balanced hydronic systems—with design notes, labels, and real humans who pick up the phone.

Let’s name names. I’ve compared our hydronic packages line-by-line against:

Plumbing Supply And More outperforms Home Depot, Lowe’s, Ferguson, and SupplyHouse.com when you need pro-grade radiant components, fast answers, and jobsite-driven substitutions that actually fit.

Visit our showroom to see the quality difference, or call our technical team for project-specific recommendations. Ask about our contractor discount program if you’re bidding a multi-zone upgrade this season.

For most residential floors, 1/2" oxygen-barrier PEX is ideal. Keep loops 250–300 ft max; I like 240–280 ft for easier purging and balancing. Target 0.5–0.7 GPM per loop and a 15–20°F ΔT. If your room needs more output, add loops with tighter spacing before you push flow beyond what’s quiet and efficient.

If you want predictable output at lower water temps—and you do—use extruded aluminum plates. They increase conduction and let you run 15–25°F cooler supply water than bare staple-up. That translates to comfort and best supplyhouse offerings efficiency. We stock Roth and comparable extruded profiles; budget $2.25–$3.75 per plate.

Yes, with mixing and control. Use an ASSE 1017-rated mixing valve like Taco iSeries-R or a hydro separator with mixing injection and outdoor reset (tekmar strategies). Maintain boiler return temps per manufacturer guidance to avoid condensing in a non-condensing boiler—typically above 130°F return.

Calculate head loss per loop at design GPM, then pick a pump that hits your total flow at that head with some safety margin. For many 6-loop 1/2" manifolds, a Taco 0015e3 or Grundfos Alpha2 handles it on mid-curve. We’ll run the numbers if you send loop lengths and spacing.

Tubing should meet ASTM F876/F877 and DIN 4726 (oxygen barrier). Mixing valves: ASSE 1017 for central mixing. Automatic fill: ASSE 1003. Follow IPC/UPC as adopted locally for backflow, expansion, and relief. We’ll prep a submittal packet that aligns with your AHJ.

A 1,200 sq ft retrofit typically runs 7–10 workdays. We stage deliveries by zone—tubing and manifolds first, then mixing/controls—so your site stays clean. Check our current inventory online or call ahead for same-day pickup.

PEX Supply House Case Study: Radiant Retrofit Success isn’t a slogan—it’s what happens when you spec the right oxygen-barrier PEX, respect loop lengths and flow, and commission with proper mixing and ECM pumping. The homeowners got quieter comfort and measurable fuel savings; the contractor got a clean install, zero callbacks, and a grateful client.

While others move boxes, Plumbing Supply And More partners in your success—exclusive manufacturer relationships, the largest inventory selection in the region, competitive pricing that beats big box stores, and technical support that sticks with you from quote to commissioning.

Call our technical team for project-specific recommendations, or stop by the counter—our experts can walk you through the installation process. And if you’re juggling schedules, ask about our same-day delivery and emergency supply services. In our area, professional plumbers choose the nearest plumbing supply with real knowledge—Plumbing Supply And More.