Raypak vs Hayward Gas Pool Heaters: AVIA vs Universal H-Series

Three different water paths sit in this table. The AVIA 404A uses a copper straight-tube exchanger, the H400FDN and H250FDN use cupro-nickel as standard, and the AVIA HD uses Raypak's NiTek nickel alloy.

Raypak's argument for the straight tube is geometry rather than metal: no bends and no helical coils, so there are fewer places for scale and erosion to concentrate and the tubes stay accessible for annual maintenance. It backs that with a stainless steel combustion chamber, which Raypak contrasts with the galvanized steel common in this class, and a replaceable ProTek Shield sacrificial anode in the inlet header.

Hayward's argument is the alloy. Cupro-nickel is fitted to every Universal H-Series model at no extra charge and with no efficiency penalty, which on a salt pool or a coastal lot is the single most useful thing about that line — the material is normally an upgrade elsewhere.

Raypak's HD models take it a step further. Raypak publishes NiTek as 300% more erosion resistant than copper and 200% more than cupro-nickel, based on ASTM G73-10 (2017) liquid-impingement testing, at the same 84% thermal efficiency and the same warranty. That is a manufacturer claim on one specific test rather than an independent result, so read it as a meaningful difference in the right direction. Either cupro-nickel or NiTek is a real improvement on plain copper for a salt pool, and neither excuses acidic water or a salt cell plumbed upstream of the heater.

All four heaters publish 84% thermal efficiency, including Raypak's NiTek version — the corrosion upgrade costs money rather than performance, which is not true of every brand's heavy-duty option.

Capacity is effectively identical at the top of the table: the AVIA 404A is 399,000 BTU/hr (Raypak names the line 404 but rates it 399 MBTU/h) and the H400FDN is 399,900 BTU/hr. The H250FDN steps down to 250,000 BTU/hr at the same efficiency, which is the sensible size for an average pool with no attached spa.

Because the efficiency is level, running cost comes down to fuel price and how many hours the heater runs. If you want a materially lower gas bill rather than a different badge, the product to price is a condensing heater such as Pentair's ETi 400 at 96%, or an electric heat pump if the pool is used most weeks.

Raypak's older atmospheric Digital line, still on plenty of Florida pads, is 82% — worth knowing if you are comparing a replacement quote against what is already there.

Raypak publishes 3 years parts and labor on AVIA and AVIA HD models, copper or NiTek, in a single-family home — the same term Pentair publishes on its ETi 400. Hayward's 2026 Expert Line terms give 3 years parts with 1 year field labor, extended to 3 years field labor when the heater is sold by a Hayward Rewards dealer. Matched to the right dealer the two are level on paper; bought anywhere else, Raypak covers two more years of labor.

Both terms have edges that belong in the decision. Raypak's warranty drops to 1 year parts and labor if the heater is installed anywhere other than a single-family dwelling, excludes travel time, freight, shipping and fuel costs, and applies only to heaters bought from an authorized U.S. dealer — Raypak states it reserves the right to reject claims on units from unauthorized internet sites or marketplace storefronts.

Hayward's edge is the SKU prefix. A W3-prefixed Universal H-Series is an Open Line unit approved for online sale with 1 year parts only and no labor, against 3 years parts on the Expert Line version of the identical heater. Hayward also has no separate longer heat-exchanger term: the cupro-nickel exchanger is covered under the parts warranty as original equipment.

The common lesson is the same on both sides. The published warranty and the cheapest online price are not available at the same time, and on a gas heater the labor half is the expensive half.

A word about our own scores, because the table does not read the way this section does. The AVIA 404A comes out at 3.9 out of 5 and the AVIA HD at 4.1, against 4.6 for both Hayward heaters, even though Raypak's standard labor term is 3 years against Hayward's 1. Warranty is barely involved in that: we score Raypak 4.0 and Hayward 4.5 on warranty and support, which is worth an eighth of a point. The gap is elsewhere — durability and exchanger material, 3.5 on the copper 404A against 4.5 for standard cupro-nickel, with the NiTek HD level at 4.5; serviceability and parts, 3.5 against 5.0, because the AVIA is a newer platform with a shorter field record than the Universal H-Series and we could not verify a third-party review sample for it; and value, 4.0 against 5.0. The two lines tie at 4.5 on performance and efficiency and at 4.0 on controls. The score measures published coverage and field record, not how well the heater is built.

Raypak's advantage is that Wi-Fi is included rather than sold. Raymote is built into the AVIA and the AVIA HD, giving the homeowner temperature control and a heat-time calculator on a phone, and giving a service company fleet monitoring and diagnostics, with no automation panel and no paid accessory in between.

Its limit is the other direction. Third-party automation still reaches an AVIA the traditional way, through a two-wire or three-wire dry-contact remote; Raypak reserves the RS-485 Modbus port for its own AquaStar pumps and The Attendant. So an AVIA on a pad running someone else's automation is an on-off device with a very good app beside it.

Hayward's heaters take the opposite route. The H400FDN and H250FDN have an onboard pad with separate pool and spa setpoints and two- and three-wire remote terminals, and Hayward states they can be controlled from the Omni app when connected to a Hayward Omni control system — real integration, but only inside Hayward's ecosystem. If you want the control embedded in the heater itself, that is Hayward's OmniX generation under HS-prefixed SKUs such as HS400FDN.

Decide which you actually want: an app that works on its own, or a heater that disappears into a system you already own.

Flow is the difference most likely to affect your quote. Both AVIA models need 40 GPM minimum with a 100 GPM maximum before an external bypass is required. The H400FDN runs from 30 GPM and the H250FDN from 25 GPM, both to a 125 GPM system maximum. On a variable-speed pump that gap is a higher heating speed, more noise and more electricity every time the heater fires.

Footprint favors Raypak at the large size. The AVIA is 30.38 inches high by 23.24 wide by 32.61 deep at 135 pounds in both the 404A and the NiTek version, where the H400FDN cabinet is 34 inches wide. Step down to the H250FDN and Hayward is the narrow one at 25 inches. We are not putting a weight beside that: Hayward's product page lists the H250FDN at 165 pounds and Hayward's own Universal H-Series brochure lists 134, and neither document says which figure is packaged and which is the bare heater.

Venting and gas differ in the details rather than the principle. The AVIA is certified Category I and Category III on a 4 inch flue, indoor or outdoor with the right vent cover, wants 3.5 inches W.C. dynamic minimum on natural gas and requires a sediment trap on every installation. Hayward takes a 3/4 inch NPT connection at 4.5 to 10.5 inches w.c. on natural gas, specifies 6 inches of rear clearance and 12 inches at the sides, and uses a 6 inch indoor vent pipe on the 400 and 4 inch on the 250.

Service access is Hayward's structural advantage: front-panel-only, with universal 2 inch by 2-1/2 inch CPVC unions so a future swap does not become a re-plumb. The AVIA opens from the top and is designed as a drop-in replacement, but it is a newer platform with a shorter field record than the Universal H-Series, and we could not verify a third-party review sample for it from any source we were able to fetch.

Natural gas availability decides more of this than the brands do. Much of Sarasota and Manatee County has no gas main, which means propane — Hayward's H400FDP and H250FDP, or Raypak's P-R404A-EP-C and P-R264A-EP-C — plus a tank, a delivery contract and a higher cost per degree. Raypak asks a higher inlet pressure on propane (8.0 inches W.C. against 3.5 for natural gas), so the gas train is set up differently.

Salt pools are the norm on this coast, which is why three of the four heaters here carry a corrosion-resistant exchanger at no efficiency cost. On a barrier-island pad, or any pool whose chemistry is not tested weekly, the AVIA HD with NiTek and the cupro-nickel Universal H-Series are the two specifications worth pricing against each other.

Cold snaps matter less here than elsewhere, but the manufacturers still draw a line: Raypak does not recommend prolonged operation below 50°F water and asks that a heater started that cold be run continuously until the water warms, while Hayward publishes a 40°F minimum operating temperature. Neither is a freeze-protection device.

One last local point in Raypak's favor and one in Hayward's. Free Raymote Wi-Fi means a service company can look at your heater's fault history before driving out, which on the Gulf Coast in February is worth something. Hayward's parts depth means the board, igniter or pressure switch is usually on a shelf in this state — which is worth something on exactly the same February afternoon.