Quick Comparison
| Feature | Gas Furnace + Central AC | Heat Pump | Boiler (Steam/Hot Water) | Ductless Mini-Split | Electric Baseboard |
|---|---|---|---|---|---|
| Average lifespan | 15-20 years (furnace), 15-20 years (AC) | 10-15 years | 20-30 years | 15-20 years | 20+ years |
| Replacement cost | $6,000-$15,000 (combined) | $5,500-$12,000 | $8,000-$20,000+ | $3,000-$8,000 per zone | $200-$500 per unit |
| Heats and cools? | Yes (two separate units) | Yes (single unit) | Heat only (needs separate AC) | Yes | Heat only |
| Uses ductwork? | Yes | Yes (ducted) or No (ductless) | No (uses radiators/baseboards) | No | No |
| Energy source | Natural gas + electricity | Electricity | Gas, oil, or electric | Electricity | Electricity |
| Common in | Most of the U.S. | South, Southeast, Pacific NW | Northeast, older urban homes | Additions, renovations, new builds | Budget builds, apartments |
| Inspector red flags | Cracked heat exchanger, rusty flue | Refrigerant issues, defrost failure | Leaking pipes, asbestos insulation | Improper installation, drainage | Insufficient capacity, no thermostat |
| Best for | Cold climates with gas service | Mild to moderate climates | Older homes without ductwork | Zoned comfort, additions | Supplemental heat only |
Gas Furnace With Central Air Conditioning
This is the most common setup in American homes. A gas furnace in the basement or utility closet handles heating. A separate condenser unit outside handles cooling. They share ductwork.
From an inspection standpoint, this system gives me the most to look at. I am checking the furnace's heat exchanger for cracks (carbon monoxide risk), the burner flames for proper combustion, the flue pipe for corrosion, the blower motor, the filter, and the electrical connections. Outside, I am checking the condenser coils, the refrigerant lines, the electrical disconnect, and the concrete pad.
The Department of Energy estimates that a well-maintained gas furnace lasts 15-20 years, though I have seen plenty push past 25 with annual service. The AC condenser has a similar range.
What Inspectors Flag Most Often
Cracked heat exchangers are the big one. A cracked heat exchanger can leak carbon monoxide into the living space. When I find this, I recommend immediate evaluation by a licensed HVAC technician. Replacement of just the heat exchanger runs $1,500-$2,500, but at that point most technicians recommend replacing the whole furnace because of the labor involved.
Other common findings: rusted or disconnected flue pipes, dirty filters restricting airflow, aging condensers with worn contactors and capacitors, and ductwork that is leaking conditioned air into unconditioned spaces. None of these are usually deal-breakers by themselves, but they add up.
Cost Expectations
Full system replacement (furnace and AC together) runs $6,000-$15,000 depending on efficiency rating, brand, and installation complexity. My neighbor Dave paid $8,400 for a mid-range system last fall. A client of mine went high-end with a variable-speed setup and spent $14,200. Budget installs with builder-grade equipment start around $5,500-$7,000.
Heat Pumps
A heat pump is a single outdoor unit that both heats and cools the house by transferring heat rather than generating it. In summer it works exactly like an air conditioner. In winter it reverses the process and pulls heat from the outdoor air into the house.
They are extremely popular in the Southeast and Pacific Northwest where winters are mild. According to the Energy Information Administration, heat pump installations surpassed gas furnace installations in the U.S. for the first time in 2022, and the trend has continued.
The tradeoff is lifespan. Because a heat pump runs year-round (it is your heater AND your air conditioner), it wears out faster. The typical range is 10-15 years. I see more heat pump replacements at the 12-year mark than any other system type.
What Inspectors Flag Most Often
Defrost cycle failures are common in older heat pumps. When outdoor temperatures drop, frost builds on the outdoor coil. A working heat pump periodically reverses to melt the frost. When the defrost board or sensor fails, ice accumulates and efficiency tanks. I check for excessive ice buildup during winter inspections.
Other common findings: failing reversing valves (the component that switches between heating and cooling mode), refrigerant leaks, and auxiliary heat strips that compensate when the outdoor temperature drops too low for the heat pump to keep up. If those backup strips are not working, the house will not stay warm during cold snaps.
Supplemental heat is actually one of the things buyers overlook. In climates where temperatures regularly drop below 30-35 degrees, a standard heat pump needs help. That help usually comes from electric resistance strips, which are expensive to run. Some newer systems pair the heat pump with a small gas furnace instead. These dual-fuel setups are more efficient but also more complex and more expensive to replace.
Cost Expectations
Replacement for a standard heat pump runs $5,500-$12,000 installed. A basic 14 SEER unit on the lower end, a high-efficiency cold-climate heat pump on the upper end. Dual-fuel systems that pair a heat pump with a gas furnace add another $2,000-$4,000 to the total.
Boiler Systems (Steam and Hot Water)
If you are looking at older homes in the Northeast or Midwest, you will probably encounter a boiler. Boilers heat water (or generate steam) and distribute it through pipes to radiators or baseboard heaters throughout the house. No ductwork. No blower motor. No air filter to check.
The upside: boilers last a long time. The National Association of Home Builders puts the average boiler lifespan at 20-30 years, and cast-iron boilers from the mid-20th century frequently run for 40-50 years. I have inspected boilers with data plates from the 1960s that still heated the house just fine.
The downside: when they do need replacing, it is expensive. And boiler systems do not provide air conditioning. You need a separate system for cooling.
What Inspectors Flag Most Often
Leaking pipes and valves are the primary concern. Boiler systems have a lot of plumbing, and old plumbing leaks. I check every visible pipe, connection, and valve for signs of corrosion, mineral buildup, and active dripping.
For oil-fired boilers, I also look at the condition of the oil tank. Underground oil tanks are a particular concern because leaks can contaminate soil and groundwater. Cleanup costs can run $10,000-$100,000+ depending on severity. The EPA recommends removing or properly closing underground storage tanks that are no longer in use.
Asbestos is the other big one. Older boiler systems frequently have asbestos insulation on pipes and around the boiler itself. Undisturbed asbestos is not an immediate health hazard, but it becomes a factor during renovation or removal. Professional asbestos abatement typically costs $1,500-$5,000 for a residential boiler system.
Cost Expectations
Boiler replacement ranges from $8,000-$20,000+ depending on the type (gas, oil, electric), the distribution system (steam vs. hot water), and the complexity of the installation. A friend of mine replaced a 45-year-old cast-iron steam boiler in his 1920s colonial last winter. Total with new piping and radiator valve updates: $16,800. If you are buying a house with a boiler, factor that eventual cost into your budget.
Ductless Mini-Split Systems
Mini-splits are the fastest-growing segment in residential HVAC. Each unit consists of a small outdoor compressor connected to one or more wall-mounted indoor units. No ductwork required. Each indoor unit controls its own zone independently.
You see these most often in home additions, finished basements, converted garages, and newer construction designed for zone-based comfort. They are also popular as retrofit solutions in older homes where installing ductwork would be impractical or too expensive.
What Inspectors Flag Most Often
Improper installation is the number one issue I see with mini-splits. Because they are relatively easy to install compared to a full ducted system, a lot of handymen and general contractors install them without proper training or licensing. Incorrect refrigerant charge, poorly routed line sets, and inadequate condensate drainage are all common findings.
The condensate drainage issue deserves special attention. Each indoor unit produces condensation that needs to drain somewhere. If the drain line is not properly sloped or routed, water backs up and can damage walls, ceilings, or the unit itself. I have seen water stains under mini-split heads in houses where the installer skipped the condensate pump or ran the drain line uphill.
Cost Expectations
A single-zone mini-split (one outdoor unit, one indoor unit) runs $3,000-$5,000 installed. Multi-zone systems with 3-4 indoor units connected to one outdoor compressor run $8,000-$15,000. The per-zone cost is lower with multi-zone setups, but the upfront investment is higher.
On the repair side, mini-splits are relatively affordable to fix. Control boards, fan motors, and other common failure points typically cost $300-$800 for parts and labor.
Electric Baseboard Heat
Electric baseboard heaters are the simplest HVAC system you will encounter. Metal housing along the base of exterior walls with an electric heating element inside. No moving parts. No combustion. No ductwork. No filter.
They also provide no cooling whatsoever.
From an inspection standpoint, there is not much to flag. Either they work or they don't. I check for proper clearance (curtains, furniture, and bedding need to stay at least 12 inches away), verify each unit heats up, and confirm thermostat function.
The real concern with baseboard heat is operating cost. Electric resistance heating is the most expensive way to heat a home. The U.S. Energy Information Administration data shows that homes heated with electric resistance spend roughly 2-3 times more on heating than homes with gas furnaces or heat pumps in comparable climates.
What Inspectors Flag Most Often
Honestly, not much. These systems are simple. The most common finding is insufficient capacity, meaning the units are too small for the rooms they serve. This is especially common in additions or renovated spaces where someone installed the cheapest option to meet code.
Missing thermostats or non-functional units are the other common flags. Replacement is cheap (individual units cost $200-$500) so it rarely becomes a negotiation issue.
The Bigger Picture
If you are buying a house with electric baseboard heat, the question is not usually about the condition of the baseboards. It is about whether you want to live with them. Many buyers plan to add a heat pump or mini-split system after closing, which is a $5,000-$15,000 investment that you should factor into your offer.
How System Type Affects Your Negotiation
The type of HVAC system in the house changes the negotiation math significantly.
A 17-year-old gas furnace with no service records is a $6,000-$10,000 conversation. A 17-year-old boiler with no service records could be a $15,000-$20,000 conversation. Same age, very different exposure.
Heat pumps that are 12-13 years old should raise more budget concern than a gas furnace at the same age, because the heat pump is closer to the end of its expected life. Electric baseboards barely register as a negotiation point because individual replacement is so inexpensive.
When reviewing your inspection report, look at the system type first, then evaluate age and condition. A "15 years old, working fine" finding means very different things for a heat pump versus a boiler.
The Bottom Line
No HVAC system type is inherently better or worse. Each has strengths that match certain climates, home styles, and budgets.
Gas furnaces with central AC are the workhorse. Reliable, well-understood, moderate replacement cost. Heat pumps are efficient in mild climates and gaining ground fast, but they wear out sooner. Boilers are tanks that last decades, but they cost a lot to replace and leave you without air conditioning. Mini-splits offer flexibility and zone control, but installation quality varies wildly. Electric baseboard heat is cheap to install and expensive to operate.
When you read the HVAC section of your inspection report, the system type tells you what questions to ask and what budget to plan for. Knowing these differences puts you in a much stronger position, whether you are negotiating with the seller or planning your first year of ownership.