Every decision in a heat emergency is worse than the same decision made in April. During a heat wave the shade materials are sold out, the HVAC company has a three-week backlog, the window that will not open is discovered at 4 p.m., and nobody has time to find out which relative has air conditioning.
A pre-season audit moves all of that to a calm afternoon. It is not a cooling procedure — the cool a home without air conditioning guide owns what to do when the heat arrives. This checklist is what you do before there is any heat to respond to, so that guide has something to work with.
CDC’s preparation guidance is explicit on the equipment half of this: if you have air conditioning, have the units cleaned and serviced before heat arrives. (Source: CDC, Preventing Heat-Related Illness.) The rest of the audit is the part most households skip.
When to run it
Run the full audit once in spring, before the first heat event, and re-check the short list after any move, renovation, equipment change, or new household member. Pair it with the spring section of the seasonal energy efficiency checklist so the envelope and the equipment get handled in one pass.
Give it an afternoon. Nothing on this list is urgent, which is exactly why it works.
Section 1: Map the sun before you buy anything
Shade materials are only worth buying for windows that actually receive sun. Most households guess wrong about which ones those are.
Walk the home and note which windows get direct sun at roughly 9 a.m., noon, 3 p.m., and 6 p.m. Write it down. West-facing glass in late afternoon is usually the worst offender and often the one people shade last.
For each sun-exposed window, record:
- what shading exists now (blinds, curtains, exterior awning, trees, nothing);
- whether the window is an emergency escape opening;
- whether it is landlord-controlled, historic, or restricted by lease or condominium rules;
- whether exterior shading is physically possible and permitted.
Exterior shading intercepts sun before the glass absorbs it and is more effective than interior coverings, but it is also the option most likely to need permission. Finding that out in April costs a phone call. Finding it out in July costs the season.
Section 2: Verify the cooling equipment you think you have
Do not assume. Check.
- Central system or heat pump: has it been serviced? Schedule it now — before peak season, when technicians are available. The seasonal HVAC checklist separates what an occupant can observe from what requires a professional.
- Window or portable units: do they actually run? Test each one for a few minutes. Check that the seal around a window unit is intact and that its filter is clean.
- Filters: replace or clean them on the schedule for your system. A clogged filter makes a working system work harder in the month it matters most.
- Fans: confirm each one runs on every speed, is stable, and has an intact cord and plug. A wobbling fan on a damaged cord is a summer problem discovered in summer.
- Thermostat: confirm it works and that the cooling schedule is set for the season, not left on the winter program.
Anything that needs refrigerant, electrical work, or opening equipment is a qualified-professional job. Book it now.
Section 3: Find the windows that will not cooperate
Night ventilation only works if windows open, close, lock, and stay secure. This is the single most common gap the audit finds.
For each window you would rely on:
- Does it open and close with normal force, and latch?
- Is a screen present and intact?
- Can it be secured against falls, intrusion, and rain if left open overnight?
- Is it an escape opening that must stay usable?
EPA’s ventilation rule is conditional, not automatic: if the outdoor air is hotter than indoors, close the windows; if it is cooler, open the shades and the windows. It also advises checking outdoor air quality before opening. (Source: EPA, Extreme Heat and Indoor Air Quality.) A window you cannot secure at 2 a.m. is not part of the plan, and neither is one you should not open on a smoky night.
Note which windows are on different sides or levels — that is what makes a ventilation path possible rather than a single open window doing nothing.
Section 4: Measure your baseline
Buy or locate one indoor thermometer and put it where people actually are, not in a hallway. Note the normal indoor temperature on an ordinary warm day.
This matters because CDC’s fan guidance is a temperature threshold, not a feeling: use fans only if indoor temperatures are below 90°F, because above that a fan can increase body temperature rather than cool you. (Source: CDC, About Heat and Your Health.) You cannot apply that rule without a number, and a heat wave is a poor time to start looking for a thermometer. The fan safety warning explains why this limit is not intuitive.
Section 5: Decide where people will go
The most reliable cooling in a heat wave is often somewhere else. CDC notes that even a few hours in air conditioning helps the body stay cooler afterward, and points to shopping malls, libraries, and local heat-relief shelters. (Source: CDC, Preventing Heat-Related Illness.)
Before the season, write down:
- two air-conditioned destinations you could reach, with their hours;
- how to find local cooling centers — 2-1-1, the local health department, or emergency management;
- how each household member would get there, including anyone who does not drive;
- who cannot be left to decide alone, and who checks on them.
An address written in April is worth more than a search performed in a hot house with a dying phone.
Section 6: Identify who is at higher risk
CDC lists groups that may need additional action on hot days, including infants and young children, people 65 and older, pregnant people, people with asthma or heart disease, and anyone working or exercising outdoors. (Source: CDC, Preventing Heat-Related Illness.)
Record, per person: heat risk factors, medications and any fluid restrictions, whether they can communicate discomfort reliably, and who is responsible for checking on them. Fluid and medication instructions come from a clinician, never from a preparedness checklist.
Include isolated neighbors. The pre-season audit is the natural moment to ask who would notice if they stopped answering.
Section 7: Check the outage overlap
Heat waves and power outages arrive together often enough to plan for it. The heat power-outage plan owns the response; the audit just confirms you have what it needs:
- charged battery banks and at least one working battery-powered fan or light;
- a realistic sense of what your backup power can and cannot run — the backup power for cooling guide is blunt that air conditioning is usually out of reach;
- appliance thermometers for refrigerated food and any temperature-sensitive medicine;
- the departure trigger, written down, before anyone is uncomfortable enough to argue about it.
A one-page audit record
| Item | Finding | Action | Who | By when |
|---|---|---|---|---|
| Sun map (9/12/15/18h) | ||||
| Shading gaps and permissions | ||||
| Cooling equipment service | ||||
| Filters | ||||
| Fans tested | ||||
| Windows: open/close/secure | ||||
| Indoor thermometer placed | ||||
| Cooling destinations + transport | ||||
| Higher-risk people + check-ins | ||||
| Outage overlap items |
Keep it with the household emergency records and update it when the home, the equipment, or the people change.
What this audit deliberately does not do
It does not tell you your home is safe in a heat wave. No inspection can promise that, because the hazard depends on the weather, the building, the power, and the person. It does not authorize any equipment purchase — the cooling products comparison is a research framework, not a recommendation. And it never overrides a clinician’s instructions or an official heat warning.
What it does is remove the excuses. When the extreme heat action plan tells you to shade the west windows, move to a cool zone, and leave early, this audit is why you already know which windows, which room, and where to go.
Sources reviewed
ReadyLience reviewed current extreme-heat prevention, heat-health, indoor-air-quality, and cooling-maintenance guidance from CDC, EPA, Ready.gov, and ENERGY STAR. The 90°F indoor fan limit is cited as current CDC guidance rather than a household test result. Individual heat risk, hydration, and medication instructions come from clinicians; equipment service, refrigerant, electrical, and building modifications belong to qualified professionals and property authority. ReadyLience has tested no cooling product and recommends none.