Help! I Bought a House! Now What?

The day you get your keys, you probably have a moving truck to unload and a dozen phone calls to return. The home maintenance list can wait, but not indefinitely. A few systems in your house matter too much to leave unverified, and others have service intervals that started the moment the previous owners moved in. The good news: You do not have to address everything at once.

New homeowner, short version: Spend your first 30 days on life-safety systems: smoke alarms, CO alarms, water shutoff, HVAC filter. Use days 31 through 60 to verify your major building systems: radon test, professional HVAC service, moisture inspection, electrical panel. By day 90, build the recurring habits that keep the house running. If you follow this order, nothing will be overdue.

Who This Guide Serves

You just closed on a home and want a clear, prioritized sequence for the first three months. This guide covers physical home systems and maintenance, not logistics like address changes or insurance paperwork. After reading it, you will know which tasks are safety-critical versus routine, which you can handle yourself, and which warrant a professional.

Why the First 90 Days Set the Tone

A new home is a new set of unknowns. The previous owners may have maintained everything carefully, or they may have deferred basic tasks for years. You won’t know until you check, and the stakes are highest before you’ve done so. Right now, you haven’t confirmed whether the smoke alarms are past their service life, you don’t know where the water shutoff is, and you have no idea when the HVAC filter was last replaced. Getting through the 30-60-90 sequence closes those unknowns one category at a time. It also builds a mental model of your house that pays off for every maintenance decision you’ll make afterward.

Terms Worth Knowing Before You Start

HVAC: Heating, ventilation, and air conditioning. The system controlling your home’s temperature and air quality, typically including a furnace or heat pump, central air conditioner, ductwork, and a replaceable air filter.

Carbon monoxide (CO): A colorless, odorless gas produced by combustion appliances including furnaces, water heaters, gas stoves, and fireplaces. CO alarms sense it before concentrations reach harmful levels.

GFCI outlet: Ground fault circuit interrupter. An outlet with built-in shock protection, required in kitchens, bathrooms, garages, and exterior locations. Look for the small test and reset buttons on the outlet face.

Radon: A naturally occurring radioactive gas that enters homes through foundation cracks and soil contact. The EPA recommends mitigation when indoor levels reach or exceed 4.0 pCi/L (picocuries per liter).

Main water shutoff: The valve that cuts water supply to the entire house. Knowing its location before a plumbing emergency is the difference between a contained leak and a flooded basement.

How Your Home’s Systems Stack Up

Your house is a set of layered systems, and they fail in different ways on different timelines. Some failures are immediate safety hazards: a smoke alarm past its service life, a water shutoff valve that won’t close. Others erode performance slowly over months (a clogged HVAC filter, failed exterior caulk). Others represent hidden risks that have nothing to do with prior maintenance, including radon levels and moisture damage behind finished walls.

The 30-60-90 structure maps to these three categories. The first pass addresses things that are dangerous if missing or expired. The second pass verifies things that may be fine or may need attention. The third pass establishes habits that prevent “dangerous if missing” from recurring.

What Gets Missed and Why It Costs You

When new owners skip a structured first-pass, the problems that surface are predictable. Smoke alarms past their 10-year manufacture date lose sensor sensitivity and may not reliably detect a fire. A clogged HVAC filter restricts airflow, increases wear on the blower motor, raises energy bills, and shortens system life. Homes with water intrusion history that go unassessed before cosmetic renovation trap moisture inside walls. Elevated radon levels go undetected indefinitely because the gas has no smell, no color, and no visible sign. None of these problems announce themselves. You find them by checking.

The First 30 Days: The Life-Safety Pass

Before the boxes are unpacked, locate three things: every smoke alarm, every CO alarm, and the main water shutoff valve.

Smoke alarms. The U.S. Fire Administration specifies smoke alarms inside every sleeping room, outside each sleeping area, and on every level of the home including the basement. Walk the house and confirm coverage. Press the test button on each unit. Then flip each alarm over and find the manufacture date printed on the back. Any alarm more than 10 years old needs replacing regardless of how it performs on the test, because sensor sensitivity degrades over time. Interconnected alarms (when one sounds, all sound) are strongly recommended. Mount new alarms on the ceiling or high on a wall, at least 10 feet from the stove.

CO alarms. Install or verify CO alarms on each level of the home and outside every sleeping area. Keep them away from heating vents and furniture that could block airflow. Check the product literature for the manufacturer-specified service life, which varies by model. Like smoke alarms, CO alarms have an end-of-life signal and a replacement interval independent of battery life.

Water shutoff. Find the main shutoff valve. In most homes it is in the basement, utility room, or near the water meter. Your home inspection report should note the location. Confirm the valve moves freely: one that has been stuck open for years sometimes seizes. If it won’t turn, schedule a plumber before you need it in an emergency.

HVAC filter. Pull the current filter and replace it. This is less about whether the old filter is bad (though it probably is) and more about learning where the filter is, what size it takes, and how the housing opens. Note the size printed on the filter frame. Replace it again in 60 to 90 days during heating and cooling season, or at minimum once each season.

Days 31 Through 60: The Systems-Verification Pass

With life-safety items resolved, turn to the building systems that require more time to assess or benefit from professional eyes.

Radon test. Every home should be tested after occupancy, including newly built homes with radon-resistant construction features. Test kits are available at hardware stores and through the National Radon Services Program. A long-term kit (90 or more days) gives a more representative reading than a short-term kit, but starting a short-term test now provides useful data. If results come back at or above 4.0 pCi/L, contact a certified mitigator.

Professional HVAC service. Convention is to service air conditioning in spring and furnace in fall. If you don’t know when the last service was, schedule one now regardless of season. A technician will check refrigerant, test ignition and heat exchangers, clean components, and flag anything that needs repair before it becomes a breakdown.

Moisture and mold visual. Walk the areas most likely to have moisture problems: under sinks, around window frames, the basement perimeter, near the water heater. Look for staining, soft drywall, peeling paint, or visible mold. There are no EPA-established safe indoor mold levels. Controlling moisture is the only prevention strategy. If the home has any documented history of water intrusion, assess it before making cosmetic repairs over it.

Electrical panel. Open the main panel and check whether the circuit breakers are labeled. An unlabeled panel slows emergency response and complicates any future electrical work. If breakers are unmarked, spend an afternoon labeling them: turn on lights and appliances room by room, trip breakers until each goes dark, then label each one. While you’re there, test GFCI outlets in kitchens, bathrooms, garages, and exterior locations using the test and reset buttons on the outlet face.

Days 61 Through 90: The Rhythm-Building Pass

By this point your house has no outstanding safety unknowns. Use the final phase to set up the recurring system that keeps it that way.

Document what you found. Write down the manufacture date of every smoke and CO alarm, the HVAC filter size, the radon test result, and any open items from the professional HVAC report. A note in your phone or a shared document is enough.

Set your seasonal schedule. Furnace service each fall, AC service each spring. HVAC filter replacement every 60 to 90 days during peak heating and cooling season. Yearly reminders for exterior caulking inspection around windows and doors, siding check for early moisture signs, and garage door lubrication (springs, rollers, and hinges) every three months.

Close out open items. If the radon test came back above 4.0 pCi/L, schedule mitigation. If the moisture walk turned up anything, address the source before covering it. If the HVAC report flagged a repair, book it before the season it matters most.

Signs That Should Not Wait

These items fall outside the phased schedule:

• A CO alarm that is sounding or signaling end of life
• Visible mold covering more than a small, isolated area
• A water shutoff valve that won’t close
• A burning smell from outlets or the electrical panel
• Smoke alarms with no power and no backup battery

What You Can Handle and When to Call a Pro

Most first-30-day tasks are straightforward DIY: replacing smoke alarms, swapping an HVAC filter, locating the water shutoff. The systems-verification pass is mixed. Radon testing, GFCI testing, and the moisture visual are DIY. HVAC professional service, any electrical panel repair, and radon mitigation require licensed work. If your moisture walk reveals water intrusion behind walls, a mold remediation professional is worth calling before you invest in cosmetic repairs over the affected area.

What to Budget For

Smoke alarm replacements run roughly $10 to $30 each, with combination smoke/CO units at the higher end. Radon test kits cost $15 to $30; mitigation systems, if needed, are a larger expense that varies by foundation type and local labor. A professional HVAC tune-up typically costs $75 to $200. HVAC filters range from a few dollars to $30 depending on size and filter type. These are predictable, repeatable costs, and far cheaper than the problems they prevent.

Making the Habit Stick

The 30-60-90 plan is a one-time sprint that sets a permanent baseline. Once you’ve completed it, maintenance is a matter of keeping up with the schedule you’ve built, not catching up from an unknown starting point. Test smoke and CO alarms monthly. Replace HVAC filters on schedule. Service HVAC systems each spring and fall. Inspect exterior caulking and siding each fall before wet weather arrives. These tasks take an afternoon a season. The alternative is discovering problems after they become expensive ones.