Over 15 years of buying rental properties, I have walked away from two deals that looked excellent on paper – one listed at an 8.4% yield, another at 9.1% – because of a single detail almost nobody checks during a viewing: how much direct sunlight actually reaches the windows between November and February.
Both units faced north-northeast on a second floor, shadowed most of the day by the building next door. I didn’t take that seriously until I owned two similar units myself and watched what weak winter sun did to my occupancy rate, my tenants’ moods, and my renovation budget.
The Hidden Cost of a North-Facing Unit
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My first lesson came from a unit I bought nine years ago for 11.8 million yen. It looked fine on the floor plan, but the windows got maybe 40 minutes of direct sun a day in December. Within the first winter, the tenant reported mold on the north wall closet, and I ended up replacing 6 square meters of wallpaper at a cost of about 62,000 yen. The unit also ran a dehumidifier nearly 24 hours a day, and the tenant moved out after just 11 months, citing the cold, damp feel of the room even with the heater on.
What surprised me most was the utility data the outgoing tenant shared with me. Their winter electricity usage ran about 35% higher than a comparable tenant in one of my south-facing units, almost entirely from space heaters trying to compensate for a room that never warmed up naturally during the day. That single comparison changed how I read every listing after that.
Why I Now Check Sun Angle Before the Floor Plan
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In the Tokyo area, the sun sits at roughly 30 degrees above the horizon at the winter solstice, far lower than the 78 degrees you get in summer. A balcony overhang or a neighboring building that seems harmless in July can block nearly all direct light in January. Now, before I even look at a floor plan, I check the compass direction with a phone app and use the shadow tool in mapping software to estimate how tall nearby structures are relative to the unit’s floor level. If I can, I try to visit at two different times of day, ideally once in the early afternoon during the colder months, since that is when a weak orientation shows itself most clearly.
The Numbers That Convinced Me
Across my 9 properties, I started tracking occupancy by orientation about five years ago, and the pattern was hard to ignore. South and southeast-facing units in my portfolio run at roughly 96% average occupancy, while the two north-facing units I still hold sit closer to 78%. Turnover itself is expensive: each vacancy cycle costs me an average of 180,000 yen once you count cleaning, minor repairs, and the lost rent during the search for a new tenant. On the north-facing units, I have gone through that cycle nearly twice as often, which adds up to real money over a decade of ownership. When I add up the extra vacancy days, the mold remediation, and the higher heating complaints across just those two units, the gap comes to roughly 410,000 yen over five years compared with what a similarly priced south-facing unit would have cost me to run.
What I Look For Now
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These days I run through a short mental checklist before I make an offer on anything, because sun exposure is cheap to evaluate up front and expensive to fix after you own the building.
- South or southeast orientation, or at minimum unobstructed east-facing windows for morning light
- At least 3 meters of clearance from any building tall enough to cast a shadow across the unit in winter
- Floor level high enough that trees, fences, or a neighboring roofline do not block the low winter sun angle
- Balcony depth under 90 centimeters, since deeper balconies cut a surprising amount of light even on a south-facing unit
- Window area that looks generous relative to room size, not just code minimum
The Two Deals I Walked Away From
The first was a 3-unit building priced at 34 million yen with a listed yield of 9.1%. Every unit faced north, wedged between two taller apartment blocks that left the ground floor in near-total shade from October through March. The second was a single renovated unit at 15.5 million yen, 8.4% yield, that looked bright in the listing photos taken in summer, but a same-day visit in late November showed almost no direct sun reaching the main room past 10am. In both cases the seller’s asking price assumed occupancy and rent levels I did not believe I could sustain once tenants experienced a Japanese winter with a dim, cold-feeling room. I passed on both, and six months later a landlord friend who bought one of them confirmed my instinct: he has already had two early move-outs citing exactly the issue I expected.
Weighing Yield Against Comfort
A high yield on paper only holds up if tenants actually want to stay, and in my experience sun exposure affects renewal decisions almost as much as rent price does. I would rather buy a unit at a 6.5% yield with reliable winter sun than one at 9% that I know will fight me every heating season. The math on paper never shows you the dehumidifier bills, the extra cleaning for mold, or the tenant who leaves a five-star review complaint about a cold, dark apartment. That is the approach I use across all 9 of my properties now: check the sun before I check the spreadsheet.
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