Here is a comprehensive HVAC and plumbing price increase list for May 2026, documenting price actions across equipment manufacturers, parts suppliers, and wholesale product lines that affect HVAC contractors' job costs this month. The May 2026 increases arrive on top of cumulative price increases since 2020 that have already raised equipment costs approximately 40 percent — adding further pressure to contractor pricing models, job cost templates, and customer-facing quotes.
This is the complete list of May 2026 price increases that contractors and distributors need to know, with context for each where available.
May 2026 Price Increases — The Full List
• Williams Heating Products: 6% on Cozy and Williams residential heating products, effective May 11, 2026. Williams and Cozy are primarily wall furnaces and direct-vent heating products — increases in this category affect contractors serving the replacement heating market in older residential and light commercial buildings.
• Navien: Price increase effective May 17, 2026. Navien is a leading manufacturer of condensing tankless water heaters and boilers — the price increase affects the high-efficiency water heating and hydronic heating categories where Navien has significant market share.
• AO Smith Water Heaters: 7% increase effective May 18, 2026. AO Smith is one of the most widely distributed water heater brands in the US, covering residential tank, tankless, and heat pump water heater categories. A 7% increase on a product line this broadly distributed has significant contractor pricing implications.
• Legend Valve: 5-10% on most products, effective May 18, 2026. Legend Valve manufactures a broad range of plumbing valves, fittings, and accessories used extensively in HVAC hydronic systems — increases in this category affect hydronic heating and chilled water system installations.
May 2026 HVAC-adjacent price increases — Williams 6% on heating products (effective May 11), Navien effective May 17, AO Smith water heaters 7% (effective May 18), and Legend Valve 5-10% (effective May 18) — add to a cumulative 40% price increase since 2020 that contractors must reflect in updated job cost templates and customer-facing pricing.
Earlier May 2026 Increases Already in Effect
The May 18 ACHR News list documents these as additions to earlier May 2026 increases already announced. Contractors should note that the following were already effective in May 2026 and should be in current price books:
• WaterFurnace International: 3.9% on geothermal heat pumps and related products, effective May 25, 2026.
• Carlisle HVAC Brands: 3-5% across product lines, effective earlier in May 2026.
• Systemair/Fantech: Up to 6.5% additional on ventilation products, effective in May 2026.
• Nu-Calgon: 15% on glycols and specialty chemicals, effective in May 2026.
• Shurtape: Price increase on HVAC tapes and related products, effective in May 2026.
The Cumulative Impact — What Contractors Must Do
The May 2026 price increase cycle arrives at a particularly sensitive moment: contractor customers are already experiencing the highest installed system prices in history and showing elevated deferral rates (DuraPlas data confirmed 34% consumer deferral in 2026). Each additional price increase narrows the margin further between what customers are willing to pay and what contractors need to charge to maintain profitability.
Specific actions for contractors:
• Update price books immediately: Every increase listed above needs to be reflected in your quoting system before the next job using those products. A quote generated from April pricing for a June installation is already wrong.
• Update service agreement renewal pricing: Annual maintenance agreement renewals priced from last year's cost structure need to reflect current parts and labour costs. Service agreements that don't account for 6-7% water heater price increases create margin leakage on every warranty repair.
• Communicate proactively with commercial customers: Long-term commercial service contracts that include parts pricing should have price escalation clauses. If yours don't, begin adding them to new contracts immediately.
Frequently Asked Questions
Which HVAC products had price increases in May 2026?
May 2026 price increases confirmed by ACHR News include: Williams/Cozy heating products (6%, effective May 11), Navien (effective May 17), AO Smith water heaters (7%, effective May 18), Legend Valve (5-10%, effective May 18). Earlier May increases include WaterFurnace (3.9%), Carlisle HVAC Brands (3-5%), Systemair/Fantech (up to 6.5%), Nu-Calgon (15%), and Shurtape.
How much have HVAC prices increased overall since 2020?
Cumulative HVAC equipment and parts price increases since 2020 total approximately 30-40% depending on the product category — reflecting material cost inflation, supply chain disruption, refrigerant transition investment, and ongoing incremental price actions from manufacturers responding to continued cost pressure.
