Age alone does not decide suitability
A house’s construction date does not tell you its present heating load, duct condition, or electrical capacity. A 1920s house with thoughtful upgrades can differ sharply from an untouched house of the same size. Start with the building as it exists today and the renovations already planned, rather than assuming that an older home is either unsuitable or ready for a simple swap.
PNNL’s ductless installation guidance calls for load calculations, indoor-unit layout, electrical assessment, condensate routes, and commissioning. Those categories make a useful starting agenda even if a ducted system is ultimately selected.
Make a room-by-room problem list
Record which rooms are cold in winter or hot in summer, whether doors are normally closed, where drafts occur, and whether the current system maintains the temperature you want. Add any attic conversion, replacement windows, or air-sealing work expected before installation. Give that list to every bidder.
A contractor should not simply copy the capacity of the old furnace. Nor should the new heat pump be expected to cure every comfort problem by itself. The Manual J guide explains the information that connects the house to appropriate equipment selection.
Six checks before a quote becomes a commitment
| Check | Evidence to request | Why it changes the project |
|---|---|---|
| Building envelope | Insulation and air-leakage assessment | Changes heating and cooling demand |
| Distribution | Duct condition or room-unit layout | Determines whether heat reaches the rooms |
| Electrical system | Professional capacity assessment | Identifies service, circuit, or load-management work |
| Outdoor location | Clearance, access, snow and drainage plan | Avoids siting problems |
| Interior routes | Piping, condensate and finish-work plan | Reveals disruption and restoration costs |
| Controls and backup | Written operating sequence | Sets expectations during cold weather and faults |
Treat these as investigation categories, not instructions to open electrical panels or disturb old insulation. Suspected hazardous materials should be assessed by appropriately qualified specialists before building work.
Coordinate envelope work and sizing
If major insulation or air sealing is already funded, ask the designer to calculate the post-improvement load and specify the assumptions. Otherwise, sizing for the current house and then substantially reducing its load can leave equipment poorly matched to the improved building.
Do not delay an urgent safe-heating replacement indefinitely while waiting for a perfect renovation. In that situation, discuss realistic near-term improvements and the equipment’s operating range. Separate committed work from work you merely hope to do. A proposal that assumes an attic upgrade that never happens may understate the load.
See whether attic insulation should come first for a sequencing framework. An energy assessment can identify where further investigation is useful; it is not an automatic instruction to replace every window.
Evaluate ducts rather than assuming reuse
Existing ducts may be useful, but their presence is not proof of suitability. PNNL’s heat pump replacement checklist addresses damaged or disconnected ducts, leakage, load calculations, airflow balance, and verification at commissioning.
Ask whether the proposed system needs return-air changes or duct resizing, and who restores access openings. For a home without ducts, compare ductless room coverage with the cost and disruption of new duct routes. Keep bedrooms and bathrooms in the conversation; a central hallway unit is not a substitute for a documented distribution plan.
Keep the budget honest
Separate equipment and installation from electrical work, ductwork, access, finish repairs, permits, and any necessary specialty assessment. Obtain a clearly defined base scope and priced alternatives. An example allowance is not a binding price for concealed conditions; ask how change orders are approved.
If the existing boiler or furnace will remain, clarify whether it is backup, supplemental room heat, or temporary equipment for a staged conversion. Overlapping systems need deliberate controls and user instructions. The ducted-versus-ductless comparison can help organize the alternatives.
The useful outcome of a site visit
Leave with a sketch of equipment locations, a room-coverage explanation, the load-calculation assumptions, an electrical-work boundary, and a list of exclusions. Enter comparable scopes in the quote tool. A complete retrofit proposal explains how the technology fits the building; it does not rely on the house being either “too old” or “easy” without evidence.