Heat Pump Boiler Sizer

Hydronic heat-pump / heat-recovery chiller sizing for boiler replacement

Projects

Scenarios

Smart Intake & File Analysis project-level — existing system data shared across all scenarios

⚙ AI settings — only needed when running this as a local file or your own host

Two ways to run the AI on your own host: (1) a proxy URL — a Cloudflare Worker that holds the key server-side (see proxy/README.md), so no key ever touches this page; or (2) an API key — your browser then calls Anthropic directly (held in memory only, never saved, but readable in this page, so use a scoped key). The proxy URL is saved in this browser only. Inside Claude.ai you need neither.

01Existing equipment

⇪ Photo of nameplate / unit AI reads model, serial, capacity, eff…

and / or type details

existing plant —

02Utility bills

⇪ Drop / choose bill CSV date, therms, gas$, kWh, elec$

or annual totals

03Existing system trend data

⇪ Drop / choose BMS trend CSV timestamp, supply °F, return °F, GPM, OAT…

04Proposed equipment cut sheet

⇪ Drop / choose cut-sheet PDF heat pump submittal / spec sheet

Flow: ① bring in data → ② confirm the sizing inputs → ③ review results & cost on the right.

Load & Existing Conditions shared

I know my…

Current system — the design basis your existing terminals were sized around

Existing supply (°F)

Existing return (°F)

Indoor design temp (°F)

Terminal type temp sensitivity

Design heating load (MBH)

Computed flow / ΔT

— ΔT —

Source & Performance scenario

Project location sets design temp & climate run-hours

Heat-pump source

Design source temperature (°F outdoor air)

Heat-pump delivered — what the proposed unit can actually produce

HP supply (°F)

HP return (°F)

Performance assumptions

2nd-law (Carnot) efficiency η · 0.40–0.55 typical

Condenser approach (+°F)

Evaporator approach (−°F)

Sizing Strategy scenario

Plant configuration

Replacement approach

Module nominal capacity (MBH, optional)

Redundancy N+1 (one standby module)

Selection oversize factor ×, on design capacity

Electrical assumptions

Voltage V

Phase

Power factor

Run Time & Operating Cost sharedoptional

How do you want to define run time?

Equivalent full-load heating hours EFLH/yr · 24/7 = 8,760

Energy basis used in savings

— —

Seasonal COP blank = auto

Boiler efficiency η

Electricity $/kWh

Gas $/therm

Sizing Result

HP heating capacity

—MBH

at design conditions

Design COP

—

heating

Electrical input

—kW

— A

Suggested selection

—

nominal capacity

Delivered Temp & Terminal Check can the existing terminals heat the space?

Plant Configuration modules, redundancy & turndown

Feasibility & Checks

COP Sensitivity

Annual Operating Cost all-electric vs boiler

Scenario Comparison all scenarios in this project

Screening tool for early-design and proposal use. COP is modeled as Carnot efficiency × 2nd-law factor across the source-to-sink thermal lift, not manufacturer performance data — always confirm selections against AHRI-certified capacity and COP at your exact entering/leaving conditions, and verify low-ambient derate, defrost penalties, and minimum source temperatures with the equipment vendor.