Hot water baseboard heat is one of the better systems ever put in a Puget Sound house. Quiet, even, no blowing air, no dust getting kicked around. If you grew up with it, you probably like it.
It also has two problems that get worse every year. It cannot cool your house, and depending on what fuel feeds the boiler, it can be expensive to run. When a 30-year-old boiler starts asking for money, most homeowners aren't deciding between a new boiler and a heat pump on heating alone — they're deciding whether to keep paying for a heating-only system in a region that now gets real summer heat.
Here's the honest version of how that conversion actually works, what it costs, and when we tell people to keep the boiler.
Hydronic baseboard is not electric baseboard
This distinction drives everything, including the money.
- Electric baseboard is a resistance element in a metal enclosure, wired to a breaker, controlled by a knob on the wall or a line-voltage thermostat. No plumbing, no boiler.
- Hydronic baseboard is fin-tube copper carrying hot water from a central boiler, controlled by zone valves or circulator pumps. There's a mechanical room, a pump, an expansion tank, and pipe running through your floors and walls.
Electric baseboard conversions are the cleanest rebate case in the region, because you're eliminating electric resistance heat. Hydronic conversions are messier: the boiler might be gas, oil, propane, or electric, and each one changes both the operating-cost math and the incentive picture. Getting this wrong is how homeowners end up disappointed, so we ask what's in the mechanical room before we quote anything.
What a heat pump actually replaces here
A heat pump moves heat with refrigerant and delivers it with air. It cannot be plumbed into fin-tube baseboard. So a conversion is never a swap — it's a new distribution system installed alongside the old one.
Option 1: ductless mini-splits (the usual answer)
For a house with no ductwork, ductless mini-splits are the honest recommendation the overwhelming majority of the time. Wall-mounted heads go in the rooms that matter, refrigerant lines run to one outdoor unit, and no framing gets torn open. Standard Puget Sound markets run $8,000 to $14,000 installed; affluent markets $9,200 to $16,800; Bellevue, Gig Harbor and Fox Island $10,000 to $18,900. Zone count and equipment tier drive the number far more than brand does — the full cost breakdown by zone count walks through it.
The trade-off is visible equipment. A head on the wall is not invisible the way baseboard under a window is. Most people stop noticing in a week; some never make peace with it. We'd rather say that out loud than have you find out after install.
Option 2: a ducted heat pump with new ductwork
If the house has a good attic or crawl space and you want conditioned air out of registers instead of wall units, a ducted heat pump runs $12,000 to $18,000 in standard markets. But a hydronic house has no ducts, so add ductwork at $3,000 to $8,000 for a standard home or $4,000 to $10,000 for a larger or more complicated layout. That's a $15,000-to-$28,000 project instead of a $10,000 one, and in a finished two-story with plaster walls it's often not physically practical at all.
We price it when the house supports it. In older Puget Sound homes with hydronic heat, it usually doesn't.
Option 3: heat pump primary, boiler as backup
If the boiler is relatively young and working, this is frequently the smartest first move. Install the heat pump for both heating and cooling, run it as the primary system, and leave the hydronic system in place set to a low backup temperature. On the handful of genuinely cold nights, the baseboards pick up the slack in the rooms without heads.
Costs nothing extra to keep hardware you already own. It also buys you a season of real data before you spend money decommissioning anything.
What happens to the boiler and the baseboards
Three separate questions people tend to blur together.
- Do the baseboards come out? Only if you want them to. They're inert once the water is drained. Most homeowners pull the covers during a flooring or paint project later, not on install day.
- Does the boiler come out? Not required for the heat pump to work. If you're done with it, decommissioning is real work — draining the loop, capping the fuel supply, dealing with venting — and it's a scope we confirm and coordinate at the estimate rather than guess at over the phone.
- Does the fuel line stay? If the boiler burned gas, the gas service usually stays for a range, water heater or dryer. Oil is different: an abandoned oil tank is its own project, and we'll tell you plainly that it belongs to a tank specialist, not to us.
Rebates depend on the fuel and the meter, not the county
Two things decide whether incentive money is on the table.
Which utility bills you for electricity. Most of our service area is one regional utility, but not all of it. Tacoma, Fircrest, University Place and Fife are Tacoma Power. Seattle is City Light. Gig Harbor and Fox Island are Peninsula Light. Parkland and Spanaway are member-owned mutuals. Burien, Normandy Park, Renton, SeaTac and Tukwila are split address by address. A rebate program's language simply doesn't apply if that utility isn't the name on your power bill.
What you're converting from. Utility conversion incentives are aimed at heat pumps replacing existing electric or fossil-fuel systems, with the biggest numbers reserved for specific cases. The amount depends on what you're replacing and what you install. An electric boiler is a strong case. A gas boiler often depends on income qualification. Our 2026 guide to heat pump rebates in Washington has the details.
Two hard facts, because vagueness here costs people money: the federal 25C tax credit ended December 31, 2025 — no 2026 install qualifies. And utility rebate programs pay only through their own contractor networks, under rules that change. We check the current requirements before quoting rather than after, and file the paperwork. Programs change, so we confirm your current eligibility rather than promise a number in a blog post.
Operating cost, without the hype
Against electric resistance heat — including an electric boiler — a heat pump typically cuts heating costs 30 to 50%. That's the strongest case in the whole conversion conversation.
Against a gas boiler, the running-cost comparison depends on current rates and is much closer. The real argument there isn't the winter bill; it's that you're buying air conditioning you don't currently have, from a system that's already going in.
Against oil or propane, the heat pump usually wins on running cost and wins bigger every year the delivered-fuel market moves.
Sizing matters more in a hydronic house
Hydronic baseboard heats room by room, so the house has been comfortable everywhere for decades. A mini-split system delivers heat from a handful of points, which means design work matters. We run a Manual J load calculation on every estimate — free, not an upsell — and we size against the actual winter design temperature for your address. That number swings 12°F across our service area, from 17°F in Olympia, Lacey and Tumwater to 29°F in Tacoma and Gig Harbor. Same house, different equipment decision.
Doors matter too. Heads condition the space they can see. If bedrooms sit behind closed doors down a hallway, they need their own zones — no BTU rating fixes closed-door physics.
When we tell people to keep hydronic heat
- The boiler is young and healthy and you don't want cooling. Nothing to fix. Revisit it in five years.
- You can't accept visible indoor units and ducting isn't practical. Then a mini-split retrofit will make you unhappy, and we'd rather lose the job than install that.
- Radiant floors, not baseboard. In-floor hydronic is a different and genuinely excellent system. Adding a heat pump for cooling can still make sense; ripping out radiant rarely does.
What the install actually looks like
Most single-zone installs are finished in one day, commonly four to six hours. Multi-zone systems with three or four heads take one to two days. Each outdoor unit needs a dedicated 208/230V circuit, and older hydronic homes sometimes have a lightly loaded panel because the heat never ran on electricity — that's usually good news, and we scope the electrical work rather than guess. We pull the mechanical permit on every job, in all 45 cities we serve.
Every installation carries a 10-year parts and 10-year labor warranty.
Get a real number
Hydronic conversions have more variables than most projects: fuel type, boiler condition, zone count, utility, room layout. That's exactly the situation where one rushed bid is a bad idea.
See starting prices in about 60 seconds with the instant estimate tool, or call (253) 785-4622 Monday through Friday, 8 to 6. Varsity is owner-operated out of Federal Way, licensed VARSIHC766RJ. We're not the cheapest bid — we're the one done right by people who answer the phone after the check clears.