Three ways to cool a 1910 frame house, and why ductless usually wins in Lincolnville and Nelmar Terrace

The comparison, up front

	Window units	Ducted retrofit	Ductless heads
Fits a frame house on piers	Yes	Only with a dry crawlspace or a tall attic	Yes
Changes to plaster	None	Chases, soffits, registers cut in ceilings or floors	One small hole per head
Noise inside	Loud	Quiet	Very quiet
Humidity control	Poor	Fair to good if sized right	Good
Heating on frost nights	Weak or none	Heat pump or strips	Built in
Preservation review	Not usually	Exterior equipment only	Exterior equipment and line-set routing
Cost in words	Lowest, repeatedly	Highest	In between, once
Typical life	Short	Long	Long

That table is the summary. The rest of this page is the reasoning behind each row, written for the two neighborhoods where we have this conversation most.

What these houses are

Lincolnville’s Victorians, shotguns and cottages went up between the 1880s and the 1920s, two-story frame with porches, on brick piers, plaster and lath inside, tall double-hung windows with weights in the jambs. Nelmar Terrace, on the old north city limit, is a decade or two later: Craftsman bungalows and Colonial Revival cottages, lower ceilings, deeper eaves, the same plaster, the same lack of insulation in the walls, the same piers.

Neither was built with a cavity for ductwork. What they have is wall cavities full of knob-and-tube remnants and window weights, attics that range from generous to nonexistent, and crawlspaces that vary from dry and tall to damp and tight. The right cooling path depends on which of those the specific house has.

Path one: window units

The default for a century, and still what many of these houses run on. Cheap to buy, costly to run, loud, a security compromise in a ground-floor sash, and a visual blight on a historic facade. They remove some humidity but not enough, and they heat poorly. The honest case for them is as a stopgap during a renovation. As a permanent system in a house someone has spent real money restoring, they do not belong.

Path two: a ducted retrofit

Sometimes possible, and sometimes right. A house with a dry, tall crawlspace can take a down-flow air handler and under-floor duct with floor registers, which keeps the ceilings and walls untouched. A house with a real attic can take an up-flow system with ceiling registers, at the cost of soffits or chases to get the trunk through the second floor. The high-velocity small-duct variant, with two-inch tubing threaded through closets and wall cavities, avoids most of the carpentry at a higher equipment cost.

The drawbacks are real: ducts in an unconditioned crawlspace or attic lose energy in this climate, every register is a cut in original material, and the air handler needs a closet. When the house has the space and the owner wants nothing visible in the rooms, this is the path. In most of Lincolnville and Nelmar Terrace, the house does not have the space.

Ask for a walk-through

Path three: ductless heads

A multi-zone ductless system puts a slim indoor head in each main room, connected by small refrigerant lines to one or two outdoor units. Each head has its own thermostat and runs independently. The holes through the wall are small enough to be invisible once trimmed. Nothing goes in the attic or crawlspace.

For these houses, the advantages stack up. No ductwork to lose energy or to need a chase. Room-by-room control, so a guest room can sit at 80 all week while the bedroom is at 72. Long, low-speed run times that pull moisture out of a leaky envelope far better than a central unit that cools quickly and shuts off. Heat on the four or five frost nights without a floor furnace. And an exterior footprint that is one or two condensers in the rear yard with painted line-set covers down the back elevation.

The honest drawbacks: there is something on the wall in each room, and a head in the wrong place in a parlor with twelve-foot ceilings looks like exactly what it is. Placement is design work. High on a secondary wall, above a casing, in a color near the trim, or as a ceiling cassette where there is a cavity. We spend time on this before the quote because it is what owners remember.

Install day in a historic house

A ductless install in Lincolnville or Nelmar Terrace is a two- or three-day job for a typical house. Drop cloths over heart pine. Heads located and marked with the owner present. One hole per head, drilled with a core bit sized to the line set and sleeved. Line sets run down the rear or side elevation in covers painted to match, never across the front. Condensers on stands set above the highest water the owner has seen, which on the lake side of Lincolnville is not a formality. Condensate routed to a drain or a dry well, not onto a neighbor’s path. Every flare fitting torqued and leak-tested before the covers go on, because the one failure these systems have in later years is a flare made in a hurry.

Where the house sits inside the city’s preservation zoning, the exterior placement and screening are reviewed before anything is ordered. Ask early whether Cook’s prepares the application or provides the owner with the drawings and photographs. [[CONFIRM WITH JERRY]]

Living with it

Filters in each head rinse under a tap monthly. The outdoor coils get a hose rinse after the February pollen. Heads are set and left; the temptation to switch them on and off room by room costs efficiency. A maintenance visit twice a year checks charge, drains and the flare fittings. Done this way, a ductless system in a historic frame house is the quietest, driest and least visible cooling the house has ever had, and the window units go to the curb.