Field Manual · No. 01
Forgotten engineering, matched to your climate
Cool your house
without the big AC bill.
Seven low-tech cooling systems the modern economy left behind — and the honest map of which one actually works where you live.
§01 · The decision map
Most "cut your AC bill" videos skip the one thing that decides everything: your climate.
A whole-house fan that's magic in dry Colorado is useless in humid Georgia. Before a single instruction, this book tells you which systems are worth your weekend — and which to skip.
| System | Dry / arid | Humid (South / SE) |
Desert (hot nights) |
Mixed / temperate |
|---|---|---|---|---|
| Night-flush whole-house fan | ●●● | ✕ | ✕ | ●● |
| Attic vent + radiant barrier | ●●● | ●● | ●●● | ●●● |
| Cool / reflective roof | ●●● | ●● | ●●● | ●● |
| DIY evaporative (swamp) | ●●● | ✕ | ●● | ● |
| Earth-tube / earth-air | ●● | ● | ●● | ●● |
| Thermal mass / PCM | ●● | ✕ | ✕ | ●● |
| Shade + cross-vent + fans | ●●● | ●●● | ●● | ●●● |
Answer three questions about your summer — daytime high, nighttime low, humidity — and the book points you to the 2–3 systems worth building, with the real numbers to build them.
§02 · Straight from the comments
The internet is full of cooling "hacks." Half of them can't work where you live.
These are real reactions to the exact systems in this book. They're not complaints — they're the whole reason the climate map comes first.
"Great — except for those of us that have 99% humidity most of the summer."
Whole-house fan · 27 likes"My house does have this. And you want to know why it's never used? Humidity."
Night ventilation · 9 likes"Salt attracts moisture. You don't want that in your walls."
Salt / PCM · de-hyped inside"My HVAC tech said the attic fan probably added 20 years onto the unit's life."
Attic venting · believer§03 · Contents
Eight chapters. Diagnose first, then build only what fits.
- Your Climate, Your SystemThe 3-question diagnosis + the full decision mapStart here
- Shade, Cross-Ventilation & Ceiling FansThe free baseline that works in every climateAny climate
- Attic Ventilation + Radiant BarrierThe near-universal attic-load killerAny climate
- The Cool / Reflective RoofReflect the sun before it becomes a billHot & sunny
- Night-Flush Whole-House FanThe $200 flagship — scoped honestly to dry, cool-night climatesDry nights
- DIY Evaporative (Swamp) Cooling15–30°F off dry air — and why humidity kills itDry only
- Earth-Tube / Earth-Air CoolingThe "buried pipes" system — with the condensation truthEarthworks
- Thermal Mass & PCM, De-HypedThe "$4 salt" idea — what's real, what to never doDay–night swing
§04 · Honest fit
This isn't for everyone. Here's the line.
Build this if you…
- Own your home and can turn a wrench on a weekend
- Want the real numbers — sizing, materials, where to buy
- Are tired of a summer electric bill that keeps climbing
- Prefer a system you understand over a black-box AC
Skip it if you…
- Rent and can't touch the roof, attic, or walls (Ch. 1–2 aside)
- Want a single magic gadget that works everywhere — it doesn't exist
- Expect these to replace AC in 99%-humidity heat (they won't)
- Won't read a climate table before spending money
The Low-Tech Cooling Playbook
30-day, no-questions refund. If the climate map says none of it fits your area, ask for your money back — keep the book.
Not sure yet? Start with Chapter 1, free.
Get "Your Climate, Your System" — the full decision map and the 3-question diagnosis — in your inbox. No system, no spend, decide for yourself.
✓ You're on the list — Chapter 1 is on its way.
§05 · Straight answers
Questions, answered honestly.
I live somewhere humid. Is this book useless for me?
No — but it will tell you the truth. Night-flush fans and swamp coolers won't save you in high humidity, so the book steers you to what does: attic venting, radiant barriers, cool roofs, shade, and airflow. The climate map is built so you never waste a weekend on the wrong system.
Will any of this actually replace my air conditioner?
In the right climate, a night-flush fan can carry most summer nights. Everywhere else, these systems cut the load your AC fights — a lower bill, not always a torn-out unit. We never promise "replace your AC" without naming the climate it's true in.
Do I need to be handy or hire a contractor?
Most chapters are genuine DIY weekend projects. A few (earth tubes, whole-house fan wiring) touch electrical or earthworks — each one flags exactly where a pro or a permit is needed. No pretending.
What about that "$4 salt in your walls" trick?
It's in the book — de-hyped. Raw salt attracts moisture and corrodes; we explain what phase-change and thermal mass really do, and the safe way to use them (and when to skip it entirely).
What do I actually get?
A single PDF you download the moment you buy — read it on a phone, tablet, or printed on the workbench. Yours forever, with a 30-day refund if it's not right for you.