#1 · RENTON
Boiler service covers the hydronic systems — radiators, baseboard hot water, in-floor radiant — common in older wet-side homes and small apartment buildings. It's specialist work; many general HVAC techs don't touch boilers.
Wet-side market range — get itemized quotes before work starts
Companies whose focus matches this work are listed first, then Renton's other top-rated hvac pros. Same no-pay-to-play ranking as everywhere on Wetside Plumbing — the formula.
Google Business data, 2026-08-07. See the full Renton ranking →
Also searched as: boiler repair replacement, boilers.
Old cast-iron boilers often run decades with care, but at 25+ years and a major failure (heat exchanger, sections), modern condensing replacements cut fuel use 20–30%. Get the repair quote and replacement quote side by side.
Hydronics is a shrinking specialty — most new construction uses forced air or heat pumps. That's exactly why we flag companies with boiler experience; check reviews mentioning 'boiler' specifically.
Ask for their Washington L&I contractor number and verify it at secure.lni.wa.gov/verify — active license, bond, and insurance. Listings above with a green badge are ones we've already matched to an active license in state records.