Dad says the smoke alarm works, and the chirping is a nuisance he has already solved by pulling the battery. The job is to install a working set of smoke and carbon monoxide alarms, from the first count to the final test, so the alarms are on the wall and the house has a record of them. Do not argue over whether he needs them. Install them as a fixed fact of the house.
Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.
Start with an inventory
Walk the house with a flashlight and a notepad. For each existing unit, note the room, the type (smoke, carbon monoxide, or combination), whether it runs on a battery or is wired to the house, and the end-of-life marking printed on the back. Replace any unit past its marked end of life rather than testing it and keeping it. Note which rooms and floors have no unit at all. Most of these jobs go wrong at this step because nobody checked the old units against the new plan.
Choose the units by power source
Pick battery-powered units where no wiring exists and the manufacturer allows it. Where the house has wired alarms, match the replacement to the same wiring setup. If any wiring work is needed, use a licensed electrician rather than improvising. Read the manufacturer's installation instructions for the exact model before you mount anything, and do not mix wired and battery units in any way those instructions forbid.
Mount where the instructions and local fire code say
Follow the manufacturer's placement rules for each unit. As a general pattern, smoke alarms go in or just outside each sleeping area and on each level of the home, and carbon monoxide alarms follow the instructions for sleeping areas and levels with fuel-burning appliances. Keep alarms away from the kitchen and the bathroom steam path, where nuisance alarms start, and off dead-air corners. If a ladder is involved, have a second person hold it. Mount the first unit where Dad will hear it from his bed, then work outward.
Test each unit in the order he will hear it
Press the test button on every unit before you leave the room. Then close the bedroom door, stand where Dad sleeps, and run the test again so you know what the house sounds like from the bed. Ask him to be present for one test. The point is not to win an argument. It is to have him hear the alarm once, with you in the room, so the sound is not a surprise later.
Turn the chirp into a schedule
A low-battery chirp means a battery needs replacing. It is not a reason to disable the unit. Record each unit's battery type on a card or in the house file, schedule a regular button test, and replace batteries according to the manufacturer's guidance. Keep a short log with the room, the unit type, the install, and the replacement plan. When a unit reaches its end-of-life marking, replace it and update the same record.
Answer the refusal with the job, not the fear
If Dad says he is careful and does not need the alarms, agree that he may be right. Then say the alarms are not for the careful days. They are for the night he is asleep through. Keep the install as a household task rather than a verdict on his judgment.
Next move
Tonight, take the flashlight tour and write the inventory from the list above. Then call your local fire department and ask whether it offers a home safety visit or can point you to the right units for the house. Start with the bedroom alarm, because that is the one he needs to hear first. More local starting points are on the Local Help in St. Louis page.