Cooling an Old Claremont House Without Rebuilding It

Every buyer who tours older houses in this town in July has the same experience twice. One house is bearable. The next one, the same age and the same size, is not.

The difference is almost never the air conditioning. It is a set of design decisions made a long time ago, some of which survived and some of which got remodeled away, and once you know what to look for you can read it from the sidewalk.

This is what the old houses here were doing about heat, and how to tell whether a particular one is still doing it.

These houses were built for this climate

Start with the point that gets lost. The older housing stock in this valley predates cheap mechanical cooling, and it was built by people who had to solve the heat problem structurally because they had no other option.

That produced a recognizable set of moves: deep eaves, porches on the exposed sides, high ceilings, tall windows placed to cross-ventilate, thick walls where the construction allowed it, and a general habit of putting the working parts of the house where the sun was not. None of it was decorative. All of it was mechanical.

A HOUSE THAT STILL HAS ITS ORIGINAL LOGIC INTACT IS A DIFFERENT HOUSE ON A HOT DAY. Not marginally. Substantially.

What gets undone

The problem is that most of these properties have been remodeled several times over, usually by people optimizing for something other than August.

The recurring casualties look like this.

EAVES SHORTENED OR REMOVED for a cleaner roofline. That overhang was shading the wall and the window beneath it during the hours the sun was highest. Without it, sun lands on glass directly.

PORCHES ENCLOSED to add square footage. Understandable, and often well done, and it converts a shaded buffer on the hot side of the house into a conditioned room that now needs cooling.

CEILINGS DROPPED during a mid-century update. Heat rises and a high ceiling gave it somewhere to go. A dropped ceiling puts it back at head height.

WINDOWS REPLACED WITHOUT REGARD TO THE CROSS-BREEZE. The original layout often had openings positioned on opposing walls specifically so air could move through. Replace some of them with fixed glass and the path closes.

SHADE TREES REMOVED. This is the biggest one and the slowest to fix. A mature tree on the west side of a house is doing more work in an afternoon than most equipment.

What to look for on a showing

You can assess most of this in a walkthrough without any technical knowledge.

Stand outside and look at the west and south faces. Is there overhang. Is there shade. Is glass exposed directly to the afternoon. That single observation predicts a great deal.

Inside, look up. Original ceiling height in the main rooms usually survives somewhere, and where it has been dropped you can often see the seam.

Open the windows, or ask to. Do openings exist on opposite walls in the same room or in adjacent connected rooms. Can air get in one side and out the other. If everything opens onto the same face of the house, there is no path.

Look for the whole-house fan. Many older properties here have one, usually in a hallway ceiling, and it is one of the best heat tools in this climate: run it at night, pull the cooled evening air through the house, close it up in the morning, and coast. It costs very little to operate compared to mechanical cooling.

Check the attic if you can get access. Insulation and ventilation up there do enormous work in a valley climate, and both are common places for an older house to be under-served.

What is worth doing

The good news is that the effective interventions in a house like this are mostly modest and mostly reversible in spirit, which suits a property with character worth preserving.

SHADE FIRST. Anything that stops sun before it hits glass beats anything that removes heat after it arrives. That is exterior shade structures, awnings, planting on the exposed sides, and, over a longer horizon, trees. It is also the cheapest category.

ATTIC INSULATION AND VENTILATION SECOND. Unglamorous, invisible, and among the highest-return work available in an old house in a hot valley.

WINDOW TREATMENT AND SEALING THIRD. Full window replacement in a historic property is a considered decision with implications beyond comfort, and it is worth taking slowly. Interior treatment, weather sealing, and careful repair often get a large share of the benefit without the same commitment.

MECHANICAL LAST, AND SIZED HONESTLY. Cooling equipment installed into a house that has lost its shade and its ventilation path is being asked to fight the building. Fix the building first and the equipment gets smaller, quieter, and cheaper to run.

The trade you are actually making

Buyers weighing an older house here against newer construction are usually told the trade is character versus efficiency. That is roughly right but it is stated too simply.

A well-preserved older house in this climate is not thermally naive. It is a passive system that works, and it was designed by people who understood this specific valley. A poorly-remodeled older house is neither: it has lost the passive system and never gained a modern one.

So the real question on a showing is not how old the house is. It is how much of its original logic is still in place, and how much of what has been done to it since was done by somebody who understood what they were undoing.

That question is answerable in twenty minutes on site, and it is one of the more useful things a buyer can learn to see.

The lifestyle guide covers the wider picture of living here, the seasons of light guide explains why orientation and shade carry so much weight in this valley, and the front-porch guide covers the social half of a feature that started life as a heat solution.

Anthony Grynchal has been licensed in California since November 2009. If a summer showing is possible, take it, and stand in the west-facing rooms in the afternoon rather than the morning.