Where to start › When a parent moves in › The thermostat wars
The thermostat wars
Nobody warns you that the most persistent argument in a multigenerational house won't be about money or medicine. It will be about the thermostat. You're sweating in a house set to 78; your mother is in a cardigan asking who left it so cold. Both of you are reporting honestly.
Their 78° is not your 78°
NIA's cold-weather guidance puts it plainly: aging, health conditions and medicines can all affect a person's ability to stay warm, and their ability to notice that they are getting dangerously cold.[2] Two different bodies in the same room are reading different instruments, and the older one has a less reliable gauge.
This page used to go further, describing a less responsive hypothalamus, later and weaker sweating and shivering, reduced skin circulation, and named drug classes that change how warm a person feels. That may well all be accurate — the reviews it cited are behind a CAPTCHA and we could not re-open them to check what they actually said, so we have taken the detail out rather than keep citations we cannot stand behind. The practical conclusion does not change: your parent is not being difficult.
The study people quote, at its real size
There is one finding that gets cited whenever this comes up, and it is worth knowing how small it is before you use it in an argument. Researchers followed 47 older adults in Boston for 12 months, measuring the temperature in their homes and asking about difficulty keeping attention. The lowest odds of reported difficulty fell between about 68 and 75°F, and the odds roughly doubled for every 7°F outside that range.[1]
What that is: an observational study of self-reported attention in 47 people. What it is not: a universal cognitive safety threshold, a diagnostic test, or evidence that changing the thermostat changes anyone's thinking. If your father seems foggier on cold days, this study is a reason to note the pattern and mention it, not a reason to conclude you have found the cause.
Used carefully, though, it is still useful: it hands the household a range to negotiate around instead of two opinions, and a range means there is a point inside it you can both live with.
The safety floor, which is a separate question
NIA advises keeping home heating at at least 68°F during cold weather.[2] That is not about comfort or attention. It is about the fact that an older body can get into trouble without much warning, which is also why, during a heat wave or a cold snap, checking on someone beats asking them how they feel.
Suspected hypothermia is an emergency. Call 911.[2]
Calling the truce
- Heat the person, not the house. Set the shared spaces at the top of what the rest of the household can stand, then close the gap on their side: warm socks and slippers, a lap blanket, a cardigan kept on their chair.
- If you add a heater, follow the heater rules. CPSC says to keep a portable electric heater at least three feet from anything combustible, plug it directly into a wall outlet rather than an extension cord or power strip, and turn it off when it is unattended or while sleeping.[3] In their room only, clear of bedding.
- Zone what you can. A closed door and a cheap room thermometer beat one thermostat governing everybody. If the house has zoned heating or a ductless unit in their room, this argument largely ends.
- Aim the shared rooms at 68–75°F as a starting point from the study above, then adjust by what people actually say.
- Make a list rather than have the conversation again. Which rooms people use, the temperature in each, where the drafts are, what each person wears, and what they find comfortable. Agree when you will check it again in unusual weather. The older person's preference belongs in that list, not outside it.
- Take a sudden change to the doctor, not the thermostat. If someone is newly cold all the time, that is a medical mention. NIA's own guidance is that health conditions and medicines affect the ability to stay warm.[2] The questions to ask has how to raise it.
One caution on using any of this: a study range is not a reason to dismiss somebody's discomfort or to explain away a new symptom.
Quick answers
Why is my elderly parent always cold?
Aging, health conditions and medicines can all affect how well someone stays warm and whether they notice dangerous cold — that is NIA's own framing, and it is why "just put a sweater on" misses the point. We have removed the detailed physiology this page used to give (hypothalamus response, skin circulation, nerve sensitivity, named drug classes) because the reviews it rested on are behind a CAPTCHA and we could not re-open them. A new or persistent change in how cold someone feels is worth raising with their clinician rather than solving at the thermostat. [2]
What indoor temperature is best for seniors?
There is one study people quote, and it is smaller than the headline suggests. Researchers followed 47 older adults in Boston for 12 months, measuring home temperature and asking about difficulty keeping attention. The lowest odds of reported difficulty fell between about 68 and 75°F, and the odds roughly doubled for every 7°F outside that range. That is an observational study of self-reported attention in 47 people — a useful number to negotiate around, not a prescription. Separately, NIA advises keeping home heating at least 68°F in cold weather. [1, 2]
How do families settle thermostat disagreements in a shared house?
Set the shared rooms at a number both households can live with, then close the remaining gap on the older person's side with layers, a lap blanket, and warmth in their own room rather than the whole house. If you use a portable electric heater, CPSC says keep it at least three feet from anything combustible, plug it directly into a wall outlet, and turn it off when unattended or asleep. Room-level zoning ends the argument outright where the heating allows it. [3]
Sources and what they support
Sources checked 2026-09-17 and 2026-09-19 using AI-assisted editorial research. This is a source check, not a clinical review.
- Baniassadi et al., home temperature and attention in older adults (PMID 39656181). Supports the 47 participants in Boston, the 12-month observation, the lowest odds of reported attention difficulty between roughly 68 and 75°F, and the doubling of odds about every 7°F outside that range. An observational study of self-reported attention in a small sample: it cannot establish cause, does not set a safe or unsafe temperature, and 47 people in one city is not a national finding. Checked from the published abstract on 2026-09-17; the abstract page is CAPTCHA-gated and was not re-opened on 2026-09-19.
- National Institute on Aging, cold weather safety for older adults. Supports the advice to keep home heating at at least 68°F in cold weather, that aging, health conditions and medicines can affect both the ability to stay warm and the ability to notice dangerous cold, the instruction to treat suspected hypothermia as an emergency, and the direction to raise new or persistent changes in temperature tolerance with a clinician. General public safety guidance for cold weather: it does not quantify comfort at any temperature, does not address heat, and is not a substitute for the person's own doctor on why they feel cold.
- US Consumer Product Safety Commission, space heater, furnace and fireplace warning (2023). Supports the three specific precautions used here: keeping a portable electric heater at least three feet from combustible materials, plugging it directly into a wall outlet rather than an extension cord or power strip, and turning it off when unattended or while sleeping. A consumer safety advisory from 2023 about portable heating equipment generally. It does not evaluate any particular heater, does not cover fuel-burning appliances' carbon-monoxide precautions in detail, and following it does not make a heater safe in a room with someone who may not remember it is on.
This page's prose is the version that was live before the 2026-09-17 citation pass, with the citations attached to it and the claims trimmed to what the sources support. Removed for want of a retrievable source: the detailed physiology of aging thermoregulation and the named medication classes, which rested on two CAPTCHA-gated reviews; the attribution of the attention finding to an institute blog post rather than the study; and the framing of the study range as a "cognitive-health setting".