Plan the heat pump while your renovation is still on paper, before walls and ceilings close. That way we run the load at 14°F for the finished house, route ducts and 240-volt circuits through open framing, and file the DOB, historic or association approvals alongside the building work. At Perennial DC Heat Pumps we install ducted systems across Washington, DC; this article is a planning checklist, not an account of any project.
What’s changing in the house?
Start by listing the committed changes that affect heating and cooling: an addition, a finished attic or basement, a reopened stair, new windows, wall or roof insulation, air sealing. Each one moves the heat loss at ENERGY STAR’s 14°F DC design temperature or the heat gain at 94°F. Ideas still under discussion go on a separate list.
Our sizing guide explains why the old unit’s size means little after a renovation. Insulation and air sealing can lower the heat loss enough that a smaller system fits, while an addition raises it. Equipment sized “just in case” for an addition that never happens can short-cycle in summer.
Can we size from your architect’s drawings?
Yes, and that is the best time to do it. Send us the drawings and specifications: wall and roof assemblies, insulation levels, window types and areas. We run a Manual J style calculation on those inputs to get room-by-room heat loss and gain, which then sets both the equipment and the airflow each room needs.
Cooling gets its own check. A smaller heating load after insulation work can mean the cooling side decides the size, and our humidity guide explains why equipment bigger than the summer load pulls out less moisture. New rooms also need supply and return paths; an existing branch rarely stretches to serve an addition well.
Walls are open: what should go in now?
Open framing is the cheapest moment for duct work. New supply runs, an added return, a line-set route and the condensate drain can go in before drywall, rather than through finished ceilings later. Our ductwork service covers how we size and seal those runs.
Electrical routes need the same timing. A heat pump typically needs 240-volt circuits for the outdoor unit and the air handler or backup heat, and our load calculation shows whether your service needs a heavy-up. The electrical guide covers the DOB fees, $22 for an instant general electrical permit and $64.90 for a heavy-up. Keep filter access and the manufacturer’s service clearances around the air handler when cabinets and finishes go in.
Do you need separate permits and approvals for the heat pump?
Yes. The heat pump needs its own DC Department of Buildings mechanical or refrigeration permit, separate from the building permit, and we line it up. In a historic district or on a landmark, a new or moved outdoor unit goes through Historic Preservation Office review, and in Georgetown, exterior changes visible from public space also go to the Commission of Fine Arts. Equipment in front-yard public space needs a DDOT public space permit.
Our historic-property guide and condo guide cover placement and association approvals. Check the delivery route too: a doorway or stair that is wide open during demolition may be too narrow for the air handler once framing and finishes are back.
Will the renovation timeline affect your rebate?
It can. DCSEU’s current rebates for an ENERGY STAR ducted heat pump are $1,000 replacing electric heat and $4,000 replacing gas, or $1,500 and $5,000 for ENERGY STAR Most Efficient, with up to $2,000 for a heavy-up to 200 amps and $400 per new circuit, up to three. They are paid back after installation, and DCSEU asks for submission within 30 days.
A long renovation can blur that date. We agree with you which day counts as installation, and we keep the paid itemized HVAC invoice separate from the general construction invoice. Our rebate guide lists every document DCSEU asks for.
Plans changed mid-project: does the quote change too?
Usually. Keep a list of every renovation change that touches the HVAC scope: a moved wall, a relocated air handler, a new bathroom, a changed electrical plan. Each can change the room loads, the duct layout or the circuits, and we revise the written estimate before equipment is ordered.
Our quote checklist keeps those revisions easy to compare, and the cost guide separates our typical range of $8,000 to $18,000 from major duct and electrical work, which we price from the site visit. For a replacement estimate, send us the drawings, the committed scope and the construction schedule.
Keep the final drawings and equipment schedule with the contract. If another trade moves a route later, check airflow, service access and clearances before it gets closed in.
Questions before you decide
Should an uncommitted addition determine the equipment size?
No. We size for the building that will exist when the system starts. An uncommitted addition goes in a second load scenario so our estimate can show whether the chosen system, ducts and circuits could serve it later.
Does an open ceiling mean all duct changes are automatically included?
No. Open framing makes duct work cheaper and easier, but our estimate still lists each new run, return and register, and says who closes and finishes the opening.
What if the renovation changes after the heat-pump quote?
We recheck the heat loss at 14°F, the duct layout and the electrical load against the revised plan, and give you the revised scope and price in writing before equipment is ordered.