How do I know when to repair vs replace my HVAC system?

Use the 50% rule: if the repair costs more than 50% of replacement, replace it. Also consider system age (replace if over 15 years with major failure), repair frequency (3+ in 2 years), and whether it uses R-22 refrigerant.

When should I replace my water heater?

Replace your water heater if you see rust on the tank, leaking from the tank itself (not fittings), the unit is over 10 years old with significant issues, or you hear strange noises from sediment buildup.

How do I know if I need a new roof?

Signs you need a new roof include multiple leaks in different areas, significant curling or missing shingles, daylight visible through roof boards, sagging sections, and being over 20 years old with recurring issues.

What is the 50% rule for home repairs?

The 50% rule states that if a repair costs more than 50% of what a full replacement would cost, you should replace rather than repair. This is a starting point but should be combined with system age, repair history, and safety considerations.

Is it worth repairing an old appliance?

Generally repair if the appliance is under halfway through its lifespan and this is the first major failure. Replace if the repair costs over 50% of a new unit, parts are hard to find, or the appliance has needed multiple repairs.

Decision Guide

8 min read

Repair or Replace?

A practical framework for one of homeownership's toughest decisions

The $500 Question

Something just broke. Your contractor is waiting for an answer. The real cost isn't just the repair bill—it's making the wrong choice. We've helped hundreds of New England homeowners navigate this decision. Here's the framework we use.

Last updated: February 2026

Quick Decision Calculator

Answer these questions to get a recommendation

1How old is the system?

2Repair cost vs. replacement?

3Repair history?

4Any safety concerns?

5How long will you stay?

The 50% Rule

If the repair costs more than 50% of replacement, replace it.

This is your starting point—but not the whole picture. A 12-year-old furnace at 50% repair cost is different from a 5-year-old one. Below, we break down each major system so you can make a confident call.

System-by-System Breakdown

HVAC / Furnace

15-20 years typical lifespan

Repair Range

Typical repair cost

Replace Range

$5,500 - $12,000

Full replacement

Repair if cost is under:

$1,500

Signs you should replace:

Aged furnace showing wear and outdated components

System over 15 years old

Tech pointing at or examining major component failure (compressor, heat exchanger)

Repair costs over $2,000

HVAC unit with multiple service stickers showing recent repair history

Frequent breakdowns (3+ in 2 years)

Utility bill or thermostat display showing inefficient operation

Rising energy bills

Uses R-22 refrigerant (phased out)

View as text list

1.System is over 15 years old AND has a major failure
2.Repair would cost more than $2,000
3.You're seeing frequent breakdowns (3+ in past 2 years)
4.Energy bills are climbing despite regular maintenance
5.The system uses R-22 refrigerant (being phased out)

The Hidden Costs of "Just Fixing It"

Real Example

"A Providence homeowner spent $2,400 on HVAC repairs over 3 years before finally replacing the system for $6,500. If they'd replaced it after the first $800 repair, they would have saved $1,900—and three winters of worry."

— ZenHome project data

When Repair Actually Makes Sense

The system is less than halfway through its expected lifespan

This is the first failure and it's a known, predictable fix

The repair cost is well under 50% of replacement

You're selling the home soon (but you must disclose the system's age)

The issue is minor—a thermostat, valve, or easily-replaced part

You have a home warranty that covers the repair

Quick Decision Checklist

1How old is the system?

Repair: Less than 50% of expected lifespan

Replace: Over 75% of expected lifespan

2What's the repair cost vs. replacement cost?

Repair: Under 30% of replacement

Replace: Over 50% of replacement

3Has this system needed repairs before?

Repair: First major repair

Replace: 2+ repairs in past 2 years

4Are there any safety concerns?

Repair: No safety issues

Replace: Carbon monoxide, fire risk, or leaks

5How long do you plan to stay in this home?

Repair: Selling within 1-2 years

Replace: Living here 5+ more years

Free Assessment

Still not sure?

Sometimes you need a professional opinion. A ZenHome pro can assess your system and give you honest options—no pressure, just straight answers.

Call Now Get a Free Assessment

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