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A Tacoma homeowner asked GreenBuildingAdvisor whether a proposed $39,550 air-to-water heat pump system could replace a nearly 20-year-old, slowly leaking boiler and provide both space heating and domestic hot water. The submitted question lists equipment and installation work, but the source provides no expert reply or confirmation that the design will meet the home’s needs.
A Tacoma homeowner is considering a $39,550 air-to-water heat pump to replace a nearly 20-year-old, slowly leaking gas boiler, and wants to know whether the proposed system can provide both space heating and domestic hot water. The question, published by GreenBuildingAdvisor, describes a 1950s, 1,750-square-foot home with hydronic heating; the source does not include an expert response or confirm that the quoted design will work for the property.
The homeowner says the house is in Tacoma, Washington, is fairly well insulated and houses two to three people. Its existing hydronic system uses staple-up heating in the main areas and radiators in four bedrooms. The boiler is described as slowly leaking, prompting concern that it may not last long enough for the owner’s preferred plan to wait a couple of years before replacing it.
The favored bid specifies a three-ton SpacePak Solstice CC32-40, described in the question as a variable-speed heat pump combi water heater using R-32 refrigerant. The listed work includes removing the boiler, installing a heat pump and buffer tank, adding pumps and associated plumbing, running insulated outdoor lines and electrical wiring, installing an expansion tank, tying in water lines, purging and commissioning the system, and obtaining a permit. The quote includes first-year maintenance and a stated warranty of 10 years on the compressor, five years on parts and one year on labor.
The homeowner reports that the current system’s design water temperature is 140 degrees at 20 degrees outdoors, with the indoor temperature set at 68 degrees. They say they would like to move away from natural gas and describe local electricity as hydro-powered and costing $0.09; the source does not specify the billing unit or provide a full energy-cost comparison. The owner asks whether the proposed equipment can also handle domestic hot water, avoiding a separate heat pump, and what details should be checked before accepting the bid.
The Boiler Must Meet Two Loads
The decision is not simply a like-for-like boiler swap. The proposed equipment is intended to serve both space heating and household hot water, while connecting to existing hydronic distribution. That makes the system’s capacity, operating temperatures and configuration important to verify for this particular home rather than infer from its nominal three-ton rating alone.
The reported design temperature of 140 degrees at 20 degrees outdoors gives a concrete condition for the contractor to address. The source does not provide heat-loss calculations, equipment performance at that outdoor temperature, or details of how the system would prioritize domestic hot water. Without those project-specific details, neither the quote nor the equipment description alone establishes expected comfort, hot-water supply, operating cost or backup requirements.
The stated electricity price and the owner’s desire to leave gas explain the appeal of electrification, but they do not establish savings. A meaningful comparison would need the home’s energy use, local rates and the proposed system’s expected performance. The $39,550 bid is a substantial commitment, and the boiler’s reported leak adds a timing concern: waiting may not be practical if the equipment fails before a replacement plan is settled.
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Existing Hydronic System Shapes the Bid
The question describes a 1950s home with hydronic distribution, including staple-up heating and bedroom radiators. The owner says the home is fairly well insulated, but provides no measured heat loss or room-by-room heating requirements. Those details matter to any assessment of whether the proposed unit and existing emitters can meet demand across the home.
The owner says a number of local HVAC contractors and plumbers do not install air-to-water heat pumps, and that several bids have been received. The preferred proposal includes a buffer tank and pump as well as new outdoor lines and electrical work, but the source does not show a complete design, competing bid details or a contractor’s explanation of system sizing. It records the homeowner’s question—not a completed installation, expert recommendation or verified result.
The quoted scope also includes a permit, commissioning and first-year maintenance. Those listed items indicate what the bid says is included; they do not independently confirm that every required component, control, or contingency is covered. The owner is asking the building-science community to identify what else should be verified before proceeding.
System Performance Is Unverified
The source includes no expert response, contractor clarification or post-installation results. It does not establish whether the three-ton unit is correctly sized, what output it can provide under the home’s stated outdoor design condition, or whether the existing staple-up circuits and radiators can heat the rooms as intended at the proposed operating temperatures.
It is also unclear how domestic hot water would be produced and controlled, whether additional storage or backup heat is part of the design, and how the system would perform during colder weather. The quote’s description calls the equipment a combi water heater, but the source does not include manufacturer specifications or a detailed system schematic. The electricity price lacks a stated unit, and there is no estimate of annual operating costs or comparison with the current gas system.
Those unknowns do not show that the proposal is unsuitable; they mean the supplied information is not enough to judge it. The source also does not report whether the homeowner accepted the bid, obtained a final design or proceeded with installation.
Questions Before Accepting the Quote
The homeowner’s next step is to obtain project-specific answers from the bidding contractor and compare them with the home’s needs. The proposal should be accompanied by a heat-loss calculation and an explanation of how the selected unit will meet the heating load, including at the stated 20-degree outdoor condition. The contractor should also explain how the existing radiators and staple-up system will operate with the heat pump, and what performance figures support that plan.
The homeowner is also seeking confirmation that one system can serve space heating and domestic hot water. That requires a clear description of the hot-water arrangement, storage, controls and any backup provision, along with the equipment’s published specifications. A written breakdown of included components, electrical and plumbing work, permit responsibilities, commissioning, warranties and any exclusions would help clarify what the $39,550 covers.
The source does not give a deadline or report a final decision. Because the existing boiler is described as leaking, the timing may depend on its condition; the homeowner has said they hoped to wait but are unsure it will hold out. No replacement date or installation outcome has been reported.
Key Questions
What replacement is the homeowner considering?
A three-ton SpacePak Solstice CC32-40 air-to-water heat pump combi water heater, with installation work quoted at $39,550, according to the homeowner’s GreenBuildingAdvisor question.
Is the proposed system confirmed to provide both heating and hot water?
No confirmation appears in the source. The homeowner asks whether it can provide space heating and domestic hot water, but no expert reply, equipment specifications or installation result is included.
What heating condition did the homeowner report?
The homeowner says the current system’s design water temperature is 140 degrees when it is 20 degrees outdoors, with the home set to 68 degrees. The source does not include a heat-loss calculation or the proposed heat pump’s output at that condition.
What does the $39,550 bid include?
The listed scope includes boiler removal, heat pump and buffer-tank installation, pumps and plumbing, outdoor insulated lines, electrical wiring, an expansion tank, system tie-in, purging, commissioning, a required permit and first-year maintenance. The stated warranty is 10 years on the compressor, five years on parts and one year on labor.
Has the homeowner decided to proceed?
The source does not say. The homeowner reports concern that the slowly leaking boiler may not last, despite preferring to wait a couple of years, but gives no final decision or installation date.
Source: rss
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