The screened lanai with no air in it
Every change below is put into the plan and the whole model is run again. That is why a pergola's winter cost shows up here without anybody having written it down, and why the cheapest thing that works is allowed to win.
Reading at
Dinner outside
What it feels like is2.4°F over— 84.8°F against at most 82.4°F
Nobody finishes a meal in a seat that is cooking.
Confidence low (30%). Treat this as a starting hypothesis, not an answer.
Move the table 6.6 ft east fixes what it feels like.
Ranked by what solves the actual limit with the least effort, not by the biggest number.
Not offered, and why
Move the table 6.6 ft east fixes what it feels like.
Slide the seating about 6.6 feet toward the east and change nothing else.
+0 hours of usable time on this day.
It does not meaningfully change the beam in either season.
Two 8.2 ft parasols instead of one fixes what it feels like.
Two parasols about 8.2 feet across, set 7.2 feet apart along the table. Between them they cover a rectangle, which is the shape a table actually is.
+0 hours of usable time on this day.
It does not meaningfully change the beam in either season.
A 13.8 ft umbrella fixes what it feels like.
A 13.8 feet canopy at about 7.5 feet, tilted toward the low sun.
+0 hours of usable time on this day.
Summer beam down about 9 per cent, winter beam up about 0 per cent at this hour.
A shade sail over the seating fixes what it feels like.
A sail about 16.4 feet by 13.1 feet, set at about 9.2 feet and angled to shed water.
+0 hours of usable time on this day.
It does not meaningfully change the beam in either season.
A drawable outdoor curtain fixes what it feels like.
A heavy outdoor curtain on a track, drawn across the west side when it is wanted and open the rest of the time.
Summer beam down about 9 per cent, winter beam up about 0 per cent at this hour.
A 6.9 ft panel to the west fixes what it feels like.
A solid panel about 6.9 feet high and 9.8 feet wide, standing 7.2 feet to the west. Low sun arrives almost horizontally, and only something vertical stops it.
It does not meaningfully change the beam in either season.
A deciduous climber on tensioned wires fixes what it feels like.
Wires strung about 8.5 feet above the seating with a vigorous deciduous climber trained across them. In leaf it shades like a light pergola; bare, it gives back most of the winter sun a solid roof would have kept.
It does not meaningfully change the beam in either season.
A 8.2 ft awning fixes what it feels like.
A folding-arm awning projecting 8.2 feet from the house wall at about 8.5 feet, retracted out of season.
It does not meaningfully change the beam in either season.
A deciduous tree 16.4 ft west of the seat fixes what it feels like.
A medium deciduous tree planted 16.4 feet to the west, grown to about 26 feet, with a crown roughly 19.7 feet across.
Summer beam down about 7 per cent, winter beam up about 0 per cent at this hour.
A pergola with open slats fixes what it feels like.
A pergola about 13.1 feet square at 8.5 feet with open slats, slats running roughly north.
It does not meaningfully change the beam in either season.
An adjustable louvred roof fixes what it feels like.
A louvred roof about 13.1 feet square at 8.5 feet, blades running north and closable.
It does not meaningfully change the beam in either season.
A solid canopy over the seating fixes what it feels like.
A solid roof about 11.2 feet above the seating, 13.1 feet by 11.5 feet, guttered on the low edge. Unlike fabric it works in rain, and unlike a pergola it takes the winter light too.
It does not meaningfully change the beam in either season.
Sit under Lanai roof does not move this in any way worth the effort.
Move the seating under Lanai roof, which is already standing and already casting something. Costs nothing and takes an afternoon of trying it.
It does not meaningfully change the beam in either season.
Change Fan light to a warmer lamp does not move this in any way worth the effort.
Swap Fan light for a 2200 kelvin lamp of the same output. Blue-weighted light scatters more in the air, spills further into the garden and reads as harsher at the same brightness. Nothing structural changes; it is a lamp.
It does not meaningfully change the beam in either season.
Shield Fan light does not move this in any way worth the effort.
Fit a full cut-off shield to Fan light so the output goes down rather than sideways. The light on the table barely changes; the light on the neighbour's wall mostly stops.
It does not meaningfully change the beam in either season.
Two low shielded lights instead of one high one does not move this in any way worth the effort.
Add a pair of shielded 200 lumen fixtures at knee height near the seating, so the useful light is where people are rather than thrown across the garden.
It does not meaningfully change the beam in either season.
Remove Fan light and mark the route instead does not move this in any way worth the effort.
Take out Fan light and put low shielded markers along the route in from the house. Being the brightest thing in a dark garden is the same as being on a stage, and the light that makes the step safe does not have to be the light you sit in.
It does not meaningfully change the beam in either season.
Horizontal fins above the opening does not move this in any way worth the effort.
A run of fixed horizontal fins projecting about 2.3 feet from The house, set above head height. Geometry does the work: high summer sun is cut, low winter sun passes under, and the view out is barely touched.
It does not meaningfully change the beam in either season.
Take up the paving and plant it does not move this in any way worth the effort.
Lift Lanai floor and plant it. Nothing else on this list moves surface temperature as far: paving in full sun sits twenty degrees or more above the air, while planted ground transpires and typically sits at or below it. It is also the only change here that gets better rather than worse over ten years.
It does not meaningfully change the beam in either season.
A ventilated timber deck instead does not move this in any way worth the effort.
Replace Lanai floor with a ventilated timber deck. Heavy paving charges all afternoon and radiates back until well after dark, which is why an evening terrace can feel hotter than the air. A light deck over an air gap is done within the hour.
It does not meaningfully change the beam in either season.
A paler paving does not move this in any way worth the effort.
Replace Lanai floor with a paler paving of similar mass. The surface itself runs cooler underfoot; the trade is that more light bounces back up at a seated person.
It does not meaningfully change the beam in either season.
A second seat 19.7 ft south does not move this in any way worth the effort.
Put two chairs 19.7 feet to the south and leave the main table where it is. The point is not to fix this spot but to stop needing it at the hour it does not work.
Summer beam up about 90 per cent, winter beam up about 0 per cent at this hour.