HVAC Tips for Older Homes in Grand Rapids

Grand Rapids is an old housing city. Drive through Heritage Hill, Eastown, Creston, Alger Heights, the West Side, or the older plats out in Wyoming and Grandville, and you're looking at homes that went up before central air was a thing anybody had heard of and, in a lot of cases, before forced air was standard either.

These are good houses. Plaster that's still flat after ninety years, framing lumber you can't buy anymore, woodwork nobody would pay to reproduce. They also fight their heating systems in ways that newer construction simply doesn't, on top of everything our lake-effect weather already does to equipment, and the homeowner usually gets told the problem is the furnace.

It's almost never the furnace.

Nearly forty years of crawling around West Michigan basements has me convinced the equipment is the least interesting part of an old house. What matters is everything the equipment is connected to.

The Ductwork Is Somebody Else's Leftovers

Start here, because it explains more complaints than anything else.

A lot of these homes originally had a gravity furnace — the octopus in the basement, a big cast iron box with huge round ducts radiating out of it. No blower. Hot air rose on its own, cool air sank back down, and the whole thing worked on physics alone. It required enormous ducts because natural convection is a weak force.

Somewhere along the line, somebody put a modern forced-air furnace in and connected it to that existing duct system. Cheapest possible conversion, done thousands of times across this city.

What that leaves you with is a blower-driven system running through ducts sized for gravity flow, and — this is the important part — almost no return path. Gravity systems didn't need much return ductwork, so they didn't have much. Today that same house often has one return grille in a downstairs hallway trying to serve two full floors.

A blower can only push as much air as it can pull back. One undersized return is a bottleneck on the whole system, and it's why the second floor never gets enough. People chase that with thermostat changes and register adjustments for years when the actual fix is adding a return upstairs.

Two related things while you're down there. Old ductwork leaks, sometimes badly, at every joint. Every cubic foot lost in the basement is heat you paid for that never reached a room. Sealing accessible joints with mastic is cheap and effective. And if the system was ever modified to add a bathroom, an enclosed porch, or a converted attic bedroom, somebody almost certainly tapped into whatever duct was nearest rather than recalculating anything. That's where the rooms that never behave come from.

The Furnace Is Probably Too Big

The original gravity furnace was enormous, because it had to be. When it was replaced, somebody looked at that data plate and sized the new one to roughly match. Twenty years later, that one got replaced the same way. And again.

So the house now has a furnace sized for a 1920s building with no insulation, no storm windows, and no weatherstripping — except that in the meantime somebody blew insulation into the attic, replaced the windows, and put new siding on with a layer of foam behind it.

That furnace is now wildly oversized for the house it's actually in. It fires, blasts past the thermostat in a few minutes, shuts off, and repeats. You get temperature swings, rooms far from the furnace that never catch up because the cycles are too short to move air that far, and a furnace burning at its least efficient point constantly, because efficiency is worst in the first minutes of every cycle. That's short cycling, and when the cause is size there's no repair for it.

The only way off this treadmill is a real load calculation on the house as it exists today, not a glance at the old unit's rating. I've put smaller furnaces into old houses more than once and had the owner tell me in February that it's the most comfortable the place has ever been. Sizing is its own subject and it's worth understanding before anybody quotes you equipment.

Order of Operations

Get this one backward and it's expensive and permanent.

Insulate and air seal first. Then size the equipment.

Every improvement to the building shell lowers the amount of heat the house needs. If you replace the furnace and then insulate, you've locked in a size that's now wrong, and you live with that for two decades.

In a pre-1980s Grand Rapids house, the highest-return work is usually:

The attic. Cheapest and most effective, nearly always. Air seal the penetrations first (top plates, chases, the hatch, can lights), then insulate over it. Sealing before insulating matters, because blowing cellulose over unsealed holes just filters the air escaping through them.

The rim joist. That band of framing at the top of the basement wall, at ground level, all the way around the house. In an old house it's usually bare wood with nothing in it, and it's one of the biggest leaks in the building. A weekend with foam board and canned foam.

Walls. Harder, since these houses have plaster and often no wall insulation at all. Dense-packed cellulose through drilled holes is the usual retrofit. Worth getting a contractor who's done a lot of it in this housing stock, and worth knowing that wall insulation in an old house needs some thought about moisture.

Windows, last. Window replacement has the worst return of anything on this list and gets sold the hardest. Storm windows plus decent weatherstripping capture most of the benefit for a fraction of the price.

One side effect worth knowing about: as you tighten an old house, it gets drier in the winter, because a leaky house is being constantly flushed with outdoor air. That sounds backward until you remember why houses go dry in the first place. It means humidity management becomes a real topic once the sealing is done.

Cooling a House That Was Never Built for It

Plenty of these homes have radiators and a boiler, which is a genuinely good heating system and worth keeping. The complaint is always summer.

Ductless mini-splits. Usually the right answer. An outdoor unit and wall or ceiling heads in the spaces that matter, connected by a small line set through a three-inch hole. No ductwork, no plaster demolition, and each zone controls itself, which suits a house where the third floor bakes and the north bedroom never warms up. Modern ones also heat, which gives you a second heat source in the rooms that need one most. The full rundown is here, and it's work we do regularly in these neighborhoods.

High-velocity small-duct systems. Two-inch flexible tubing routed through wall cavities and old chases, feeding small round outlets. More invasive than ductless, less than conventional ducts, and it preserves the look of a period room better than a wall head does. Costs more.

Conventional ductwork. Possible, and in a house built without it that means dropped soffits through finished rooms, lost closet space, and opened plaster. It's a renovation priced like one. Sometimes it's right, usually when you're gutting the place anyway. Mostly it gets chosen because it's what people know to ask for.

Two More Old-House Specifics

The chimney. Many were built for coal, converted to oil, then to gas, and every conversion left the flue larger than what it's now venting. Old liners shed tile. And if you pull a furnace off a chimney it shares with an atmospheric water heater, that water heater is suddenly alone in a flue far too big for it, drafts poorly, and can spill exhaust into your basement. A properly sized liner is the fix and it belongs in the quote from the start.

Electrical capacity. A house still on a 100-amp service, or with some original wiring in place, limits what you can add. This matters most for heat pumps with electric backup, which want real capacity. It's a conversation to have with an electrician early, not a surprise on install day.

I did a job in East Grand Rapids on a 1926 house where the owners had been through three furnaces in twenty years and each one had been "the wrong size" according to whoever replaced it next. The last contractor had gone bigger again. When I ran the load calculation, the house needed a little over half of what was sitting in the basement. But we didn't touch the furnace first. They air sealed the attic and the rim joist that fall, dense-packed the walls the next spring, and we put in a properly sized two-stage unit after that. Their gas use dropped by about a third and the third floor became usable in January for the first time since they'd owned it.

Three furnaces spent chasing the symptom. The house was the problem the whole time.