You Bought the House… Now Let’s Talk Radon

January 11, 2026

Why NH Radon Testing Still Matters (Even If You Waived the Inspection)

You found the one. The offer was strong. The market was wild. And somewhere in the chaos, the home inspection—and radon test—got waived.

First of all: you’re not alone.
Second: it’s not too late to do the right thing.

One of the most important things you can do after purchasing a home—especially in New Hampshire—is radon testing. It’s affordable, non-invasive, and could literally save lives.

Let’s break it down in plain English 👇

What Is Radon (and Why Should You Care)?

Radon is a colorless, odorless, radioactive gas that comes from the natural breakdown of uranium in soil and rock. Sounds scary? It can be.

Radon seeps into homes through:

Foundation cracks
Sump pits
Crawl spaces
Utility penetrations

According to the EPA, radon is the second leading cause of lung cancer in the U.S.—and the #1 cause among non-smokers.

And here’s the kicker for New Hampshire homeowners:

👉 New Hampshire is a high-radon state.

That makes NH radon testing not just a good idea—but a smart one.

“But I Just Bought the House…”

When Should You Test for Radon?

If you waived the inspection, the best time to test is:

As soon as possible after moving in.

Ideally:

Test during the heating season (fall–spring) when homes are closed up
Test the lowest livable level of the home (basement or first floor)
Avoid testing during major renovations or extended window-opening

Even if the home is brand new—or “never had an issue before”—radon levels can vary house to house and even season to season.

Types of Radon Tests: What Are Your Options?

There are a few types of radon tests used during an NH home inspection or post-purchase testing.

Let’s compare the most common 👇

1. Charcoal Canister Tests

Short-term tests are mailed in and can be completed DIY. Not always as accurate.

(The Simple, Budget-Friendly Option)

How it works:

A small container filled with charcoal absorbs radon from the air over a short period (typically 2–7 days).

Pros:

✅ Affordable
✅ Easy to deploy
✅ Widely accepted

Cons:

❌ Only captures a short snapshot in time
❌ More susceptible to weather fluctuations
❌ Results can be influenced by how the test is handled

Best for: Homeowners looking for a basic screening or budget-friendly option.

2. Continuous Radon Monitors (CRM)

CRM are more accurate and need to be placed by a pro. Tests can run longer (up to 10 days) for more accurate results.

(The Gold Standard)

How it works:

An electronic device measures radon levels hour by hour, usually over 48–96 hours.

Pros:

✅ Highly accurate
✅ Tracks hourly fluctuations
✅ Detects test tampering (windows opened, power loss, etc.)
✅ Preferred by professionals

Cons:

❌ Slightly higher cost
❌ Requires professional placement and retrieval

Best for: Homeowners who want the most reliable data—especially after waiving an inspection.

Why Length of Test Matters

Radon levels naturally fluctuate throughout the day due to:

Weather changes
Barometric pressure
HVAC use
Occupancy patterns

A 48-hour test is the minimum, but extending the test to 7–10 days provides:
✔ A more stable average
✔ Fewer “false low” results
✔ Greater confidence in the data

Think of it like checking the weather:

One glance out the window ≠ the full forecast
A few days of data tells the real story

When it comes to radon, more data = better decisions.

What If Radon Levels Are High?

Good news: Radon mitigation works.

If levels come back at or above 4.0 pCi/L (EPA action level):

A mitigation system can typically reduce radon by up to 99%
Installation is usually completed in one day
Systems are quiet, efficient, and affordable (Usually less than $2500)

This is a fixable problem—and a very common one in NH. We do NOT install radon mitigation systems, but check out our Local Pro’s page for contacts that do!